Solid State Research Articles

Investigation of Vanadium-Based Oxide(L1+xV3O8) for Zn-Ion Batteries

Being a champion in the portable electronics world, high-energy density lithium-ion batteries(LIBs) are irreplaceable. Still, the scarcity of Li resources, high cost, and the inclusion of non-aqueous electrolytes make them relatively perilous and inefficient for grid-scale energy storage. Recently, the blooming aqueous Zn-ion batteries (ZIBs) have emerged as one of the pioneers featuring the inherently safe nature of metallic Zn anode and its unique properties.[1] Vanadium-based compounds show fast ion diffusion and excellent reversible capacity because of their rich valence state of V, facile distortion of V-O polyhedra, and tuneable composition, which offers an excellent treasure house. Moreover, the different oxidation states of vanadium allow a higher degree of structural change and greater functional flexibility while incorporating multivalent cations into vanadium-based compounds.[2] The present work focuses on a V-based oxide cathode, i.e., LixV3O8 (x = 1, 1.3, 1.5), named LVO (SG: P21/m, crystal: monoclinic). It was synthesized using V-pentoxide and LiOH precursors through a simple and economical sol-gel route. LVO was further chemically lithiated to the desired stoichiometries (1.3 and 1.5) using LiI in acetonitrile to get Li1.3V3O8 & Li1.5V3O8, to use them as a cathode material for ZIBs. The best-performing cathode, i.e., L1.5VO, showed the reversible capacity of ~150 mAhg-1 at a current rate of 5 Ag-1 for 3500 cycles in 2 M Zn(Otf)2. Moreover, at 1Ag-1, it showed a high capacity of 260 mAhg-1. In operando XRD suggests the overall phase evolution is highly reversible, as indicated by the reversible evolution of the LVO peaks, the underlying charge storage process can be distinguished into two halves. During discharge, those two halves are: 1.6V – 0.8V window representing Zn2+ intercalation and 0.8 – 0.2V window with predominant H+ intercalation. The latter process is evident from the appearance of the triflate based layered double hydroxide byproduct (triflate-LDH) diffraction peaks (marked with asterisk) [3] formed from the reaction of Zn2+, CF3SO2O- (triflate anion), and OH- left behind after H+ insertion. It is safe to say that the Zn2+ intercalation is the dominant process in the high voltage regime where the triflate-LDH peaks do not appear. Even though the transition from Zn2+ to H+ mediated charge storage coincides with a change in the shape of the voltage profile and its slope around 0.8 V, this is likely related to the puckering of the VOx layers as observed for Li+ intercalation in V2O5. In operando Raman suggested an evolution for the peaks which are associated with the V-O-V bending vibrations in the 200-600 cm-1 range. Overall, A detailed examination of this system using ex-situ, in-operando XRD, in-operando Raman spectroscopy, solid state 1H proton NMR, and ABF-STEM imaging will be discussed, which confirmed Zn-ion (de)intercalation in Li1.5VO with a reversible LDH formation. This vanadate can be proposed as a robust cathode for zinc-ion batteries. Reference s : [1] M. Song, et al., Adv. Funct. Mater. 2018, 28,1802564.[2] Y. Zhang et al., Chem. Front. 20 21, 5, 744-762.[3] P. Oberholzer et al., ACS Appl. Mater. Interfaces 2019, 11, 674−682

Effects of Lithium Metal Storage Environment on Its Reactivity Toward Polyethylene Oxide-Based Blend Electrolytes

Lithium metal has generated significant interest as an anode material because of its high theoretical capacity (3860 mAh/g). However, issues such as dendrite growth and lithium loss during cycling make this material incompatible with current liquid electrolytes. Solid polymer electrolytes (SPE) have been proposed as a potential replacement as they are non-flammable, able to resist dendrite growth, have decent ionic conductivity and good interfacial contact with lithium metal.One aspect that is often overlooked is the fact that passivation layers, initially reported by Naudin et Al (1), often form on the lithium metal surface and are hence intrinsic to the chemical composition of the lithium surface (2, 3). According to Otto et Al (4), residual quantities of atmospheric gases are often present in lithium metal storage environments, thus electrode surface modification is inevitable. This passivation layer is expected to impact the reactivity of the lithium metal anode (LMA) towards SPE. Moreover, such phenomenon was originally described by Peled et Al as the solid electrolyte interface (SEI) (5). Lithium metal reactivity towards PEO, suspected by Galluzo et Al (6), was recently reported by Liu et Al (7), under optimized conditions (ultra-thin neat materials), but the impact of this phenomenon in a realistic LMA environment has not been extensively investigated.In this study, the impact of gas exposure on a LMA was investigated by exposing freshly cut lithium rods to O2, CO2 and N2. The resultant passivation layers were characterized via XPS. The effect of passivation layer formation on LMA reactivity towards SPE was measured by exposing samples with pre-characterized passivation layers to common SPE materials. The resultant interface was characterized using Raman spectroscopy. SPE-passivation layer reactivity was correlated to ageing properties by EIS and kinetic charge transfer characteristics in galvanostatic linear polarization at the LMA-SPE interface, in a symmetric Li – SPE – Li stack.This study revealed that the chemical composition of the lithium metal passivation layer affects its reactivity towards SPE as well as the electrochemical performance of a Li-SPE-Li symmetric cell. A thorough characterization of the lithium metal passivation layer is essential for the understanding of some of the fundamental factors affecting all solid-state lithium metal battery performance and is therefore consubstantial with the development of modified LMA. C. Naudin et al., Characterization of the lithium surface by infrared and Raman spectroscopies. Journal of Power Sources 124, 518-525 (2003).S.-K. Otto et al., In-Depth Characterization of Lithium-Metal Surfaces with XPS and ToF-SIMS: Toward Better Understanding of the Passivation Layer. Chemistry of Materials 33, 859-867 (2021).P. R. G. Zhuang, F. Kong, F. McLarnon The reaction of clean Li surfaces with small molecules in ultrahigh vacuum: II. Journal of The Electrochemical Society, 159-164 (1998).S.-K. Otto et al., Storage of Lithium Metal: The Role of the Native Passivation Layer for the Anode Interface Resistance in Solid State Batteries. ACS Applied Energy Materials 4, 12798-12807 (2021).E. Peled, Film forming reaction at the lithium/electrolyte interface. Journal of Power Sources 9, 253-266 (1983).M. D. Galluzzo et al., Dissolution of Lithium Metal in Poly(ethylene oxide). ACS Energy Letters 4, 903-907 (2019).P. Liu et al., Increasing Ionic Conductivity of Poly(ethylene oxide) by Reaction with Metallic Li. Advanced Energy and Sustainability Research 3, 2100142 (2022).

(Invited) On Solar Seawater Splitting

We are currently witnessing the widest worldwide environmental disasters and it is now crucial for the future of humanity to transition to novel societies where environmental, energy, and economic policies are no longer based on endless-growth financial models and fossil fuel technologies to decrease our environmental footprint. The origin of this strong imbalance between human activities and the environment is found in the endless-growth economic systems in place in major countries worldwide as it inherently requires the use of endless cheap energy to be sustained, hence the massive use of coal and fossil fuels as energy sources for a more profitable energy return on energy invested, which might be good for the economy but not for our environment, health, and sustainable future. Technological innovations have always helped boost the economy numerous times throughout civilizations yet it must involve large-scale, clean, and cost-effective fabrication techniques and be based on efficient earth-abundant and easily recyclable materials. A transition to hydrogen-based energy and economy is ideal as it produces zero carbon emission and hydrogen fuel cell and forthcoming hydrogen combustion transportation are available worldwide. However, most of the hydrogen produced comes from nonrenewable sources, i.e. by steam reforming of methane which produces very large amount of carbon mono/dioxide. The most natural, cleanest and sustainable way to produce hydrogen at large scale is by solar seawater splitting[1]. Our strategy is to fabricate earth-abundant and non-toxic devices consisting of oriented arrays of quantum rods/dots of high purity synthesized by aqueous chemical growth at low temperature without surfactant and with controlled dimensionalities and surface chemistry[2] with intermediate bands for high visible-light conversion, band structure edges optimized for stability against photocorrosion and operation conditions at neutral pH, low bias and no sacrificial agent. Such characteristics, combined with the in-depth investigation of their size dependent and interfacial electronic structure[3] and electrical properties[4] provide better fundamental understanding and structure-efficiency relationships for a cost-effective and sustainable generation of hydrogen from the two most abundant and geographically-balanced free resources available, the sun and seawater. An overview of such a strategy is presented for oxides, nitrides, sulfides as well as semiconductor-molecular catalysts hybrids[5], their low-cost and large scale fabrication, physical characterization, photogenerated charge dynamics, dopant segregation and thermal processing effects[1].[1] K.C. Bedin et al J. Am. Ceram. Soc. 2023, 106, 79; I. Rodriguez-Gutierrez et al ECS J. Solid State Sci. Tech. 2022, 11, 043001; J. B. Souza Jr et al Appl. Phys. Lett. 2021, 119, 200501; Y. Chen et al J. Mater. Chem. C 2021, 9, 3726; A. Tofanello et al J. Appl. Phys. 2020, 128, 063103; APL Mater. 2020, 8, 040905; Y. Wei et al Sol. Energy Mater. Sol. Cells 2019, 201, 110083; X. Guan et al ACS Energy Lett. 2018, 3, 2230; J. Phys. Chem. C 2018, 122, 13797; J. Su et al J. Phys. Chem. Lett. 2017, 8, 5228; ACS Energy Lett. 2016, 1, 121; Y. Tachibana et al Nat. Photon. 2012, 6, 511; C.X. Kronawitter et al Energy Environ. Sci. 2011, 4, 3889[2] L.Vayssieres, Adv. Mater. 2003, 15, 464; Int. J. Nanotechnol. 2004 , 1, 1; Int. J. Nanotechnol. 2005, 2, 411; J. Phys. Chem. C 2009, 113, 4733; J. Lützenkirchen et al Colloids Interfaces 2020, 4, 39[3] L.Vayssieres et al Appl. Phys. Lett. 2011 99, 183101; Adv. Mater., 2005, 17, 2320; C.X. Kronawitter et al Phys. Rev. B 2012, 85, 125109; Energy Environ. Sci. 2014, 7, 3100; Nano Lett. 2011, 11, 3855; J. Phys. Chem. C 2012, 116, 22780; PhysChemChemPhys 2013, 15, 13483; M.G. Kibria et al Adv. Mater. 2016, 28, 8388; K. Nie et al Nano Energy 2018, 53, 493; C.L. Dong et al Chem. Eur. J. 2018, 24, 18356[4] J. Wang et al ACS Appl. Mater. Interfaces 2019, 11, 2031; J. Engel et al Adv. Func. Mater. 2014, 24, 4952; I. Rodriguez-Gutierrez et al Electrochim. Acta 2019, 308, 317; Appl. Phys. Lett. 2021, 119, 071602; K. C. Bedin et al Chin. J. Catal. 2022, 43, 1247[5] T. Benko et al Catal. Sci. Technol. 2021, 11, 6411; Y. Wei et al Nano Res. 2016, 9, 156

Evolution of 2PB/3PB Transport Pathways in Oxygen Electrodes during Degradation Test: A Perspective from Electro-Chemo-Mechanical Coupling on Microstructures

The solid oxide electrolysis cell (SOEC) has garnered significant attention over the past decades for hydrogen generation integrated with intermittent renewable energy [1]. However, a major hurdle in the commercialization of SOEC is cell degradation when operated beyond 1000 hours [2]. SOEC degrades two times more quickly than the same cell operated in fuel cell mode [3]. Perovskite oxygen electrodes (OEs), such as La1-xSrxCo1-yFeyO3-δ (LSCF), exhibit flexible oxygen stoichiometry [4-6] depending on the operating conditions. The delamination failure in perovskite OEs arises from a mismatch between the slower O2 evolution rate at the surface and the rapid O2 current in the bulk from the electrolyte (EL), which causes variations in oxygen stoichiometry. This variation in oxygen stoichiometry enhances bonding, contracts lattice volume, and leads to chemical stress at the OE/EL interface [7].In this research, we aim to construct an electro-chemo-mechanically coupled model with synthetic microstructures (Fig.1a) to explore the intricate interactions between delamination at the OE/EL interface and oxygen ion transport pathway evolution. The Dream 3D software will be utilized for microstructure generation, Matlab for mesh preparation, and Comsol for Multiphysics simulation. We will examine two OE configurations known for achieving high electrocatalytic activity [8]: single layer and bilayer OEs . For the single layer configuration, La0.6Sr0.4Co0.4Fe0.6O3 (LSCF) [9, 10] serves as the sole electrode material. For bilayer OEs, we incorporate SrTa0.1Co0.9O3 (SCT) [11, 12] as the capping layer for electrocatalytic activity, with LSCF acting as the supporting backbone. The evolution of two transport pathways (Fig.1b&c), double phase boundary (2PB) and tripe phase boundary (3PB), in different configurations during long-term degradation tests will be evaluated by coupling the models with experimental polarization curves and electrochemical impedance spectra. The investigations will focus on the effects of delamination resulting from lattice volume variations on shifting of transport pathways (Fig.1d) in different OE configurations. References Nechache, A. and S. Hody, Alternative and innovative solid oxide electrolysis cell materials: A short review. Renewable and Sustainable Energy Reviews, 2021. 149.Rashkeev, S.N. and M.V. Glazoff, Atomic-scale mechanisms of oxygen electrode delamination in solid oxide electrolyzer cells. International Journal of Hydrogen Energy, 2012. 37(2): p. 1280-1291.Moçoteguy, P. and A. Brisse, A review and comprehensive analysis of degradation mechanisms of solid oxide electrolysis cells. International Journal of Hydrogen Energy, 2013. 38(36): p. 15887-15902.Adler, S.B., Chemical Expansivity of Electrochemical Ceramics. Journal of the American Ceramic Society, 2001. 84(9): p. 2117-2119.Atkinson, A. and T.M.G.M. Ramos, Chemically-induced stresses in ceramic oxygen ion-conducting membranes. Solid State Ionics, 2000. 129(1): p. 259-269.Bishop, S.R., K.L. Duncan, and E.D. Wachsman, Defect equilibria and chemical expansion in non-stoichiometric undoped and gadolinium-doped cerium oxide. Electrochimica Acta, 2009. 54(5): p. 1436-1443.Cook, K., J. Wrubel, Z. Ma, K. Huang, and X. Jin, Modeling Electrokinetics of Oxygen Electrodes in Solid Oxide Electrolyzer Cells. Journal of The Electrochemical Society, 2021. 168(11): p. 114510.Laguna-Bercero, M.A., H. Monzón, A. Larrea, and V.M. Orera, Improved stability of reversible solid oxide cells with a nickelate-based oxygen electrode. Journal of Materials Chemistry A, 2016. 4(4): p. 1446-1453.Mogensen, M.B., M. Chen, H.L. Frandsen, C. Graves, J.B. Hansen, K.V. Hansen, A. Hauch, T. Jacobsen, S.H. Jensen, T.L. Skafte, and X. Sun, Reversible solid-oxide cells for clean and sustainable energy. Clean Energy, 2019. 3(3): p. 175-201.Jiang, S.P., Challenges in the development of reversible solid oxide cell technologies: a mini review. Asia-Pacific Journal of Chemical Engineering, 2016. 11(3): p. 386-391.Huang, K. and Y. Wen, Electrochemical Performance of New Bilayer Oxygen Electrode for Reversible Solid Oxide Cells. ECS Meeting s, 2021. MA2021-03(1): p. 138-138.Huang, K., Method to Make Isostructural Bilayer Oxygen Electrode. 2020, University of South Carolina: US. Figure 1

Role of Halogen Elements in Conductivity and Electrochemical Stability of Sulfide Based Solid Electrolytes

All-solid-state batteries (ASSBs) are a promising candidate for future energy storage technology with better safety and higher energy density [1]. Safety of solid state batteries come from solid electrolytes used instead of organic liquid electrolytes in conventional Li-ion batteries. The various types of solid electrolytes have already been reported for SSBs which can be divided into oxides, sulfides, halides and polymers based on their properties, advantages and disadvantages [2]. Among them, sulfide based solid electrolytes have advantages over other due to high conductivity and ductile nature of sulfides [3]. The discovery of Li10GeP2S12 solid electrolyte called LGPS structured sulfide electrolyte have shown great potential to replace liquid electrolyte as ionic conductivity of LGPS was found 1.2×10-2 S cm-1 at room temperature comparable to the conductivity of organic liquid electrolyte [4]. However, Li10GeP2S12 electrolyte suffers with poor cyclability in solid state batteries due to reduction of Ge+4 ions to Ge0, and instable against lithium metal anode [5, 6].The solid electrolytes (SEs) with high conductivity and better stability against lithium metal are most important requirements for successful commercialization of solid state battery (SSB) technology. Therefore, in the search for new SEs with above mentioned qualities, halogen elements (Cl, Br, I) are explored in Li-P-S-O system to prepare Li10GeP2S12 (LGPS) structured SEs. In all prepared SEs, LPSOBr and LPSOI compositions show highest conductivities of 0.55 mS cm-1 and 0.67 mS cm-1 at 25 °C. The phase identification of newly synthesized solid electrolytes is done by X-ray diffractometer technique along with Rietveld refinement analysis. The conductivity of prepared solid electrolytes is determined by electrochemical impedance spectroscopy. These similar compounds also show superior stability against lithium metal in symmetric cells (Li/Ses/SE) as well as in full SSB cells (NCA/SEs/graphite) tested with LiNi0.8Co0.15Al0.05O2 cathode and graphite anode. These compounds also show 5 times higher stability in ambient environment conditions as compared to non-doped LPSO compound.

Design of Lithium Metal Anode and Other High-Capacity Alloy Anodes Solid-State Batteries in Context of Contact Loss between Anode and Solid Electrolyte Separator

Cyclic volume changes and non-uniform electrodeposition/stripping, among other cycling-induced chemo-mechanical degradation of lithium metal and lithium-alloy solid state batteries, lead to contact loss between the anode and the solid electrolyte separator[1, 2]. In-operando experiments have shown ac-celerated short-circuiting behavior due to contact loss in “anode-free” solid-state batteries[2]. Simulations reveal the relationship between active area fraction and the ratio of effective conductivities in made-up active area configurations[3]. Through modeling experiments using imputed active con-tact area of lithium-metal anode batteries, we quantify the effects of this contact loss in terms of accelerated chemo-mechanical degradation and de-creased rate capability. Specifically, we (1) quantify the interfacial resistance due to this contact loss, (2) show non-uniform local current density distribution such that local current densities could exceed lithium filament growth critical current densities, (3) show uniaxial stress inhomogeneity due to non-uniform reaction at the anode/separator interface, and (4) show non-uniform reaction distribution at the positive electrode.Besides allowing for the optimization of designs to minimize contact loss, our work sheds light on tradeoffs in the design of solid electrolyte separators.

Inverted Glasses As Ductile Lithium Ion Conductors for Solid State Batteries

Inorganic electrolytes for solid state batteries with Li metallic anodes must combine properties such as high ionic conductivity, chemical stability, and resistance to failure due to propagation of Li dendrites. Abundance of experimental evidence suggests that cracking of the solid electrolytes due to pressure exerted by lithium plating into the material defects is the primary source of failure [1]. This is due to inherent brittleness of the ceramic ionic conductors, i.e. their inability to reduce stress by means other than fracture. Unlike ceramics, plastic deformation in glass can be achieved via shear and (or) by densification. Both mechanisms can be operational in glasses with reduced content of glass formers relative to the content of glass modifiers – i.e. inverted glasses. Using the example of lithium phosphorous oxynitride, Lipon, we demonstrate how these two mechanisms are capable of accommodating applied stress while avoiding creation of new surfaces by cracking. We investigate the resistance to fracture in Lipon-like glasses and the underlying connection to their composition via instrumented nano-indentation, Raman spectroscopy, and numerical simulations. We observe enhancement of isochoric shear with increase of Li content, similarly to the reports of increased plasticity in sodium aluminoborate glases with high alkali content [2]. Nano-indentation demonstrates that Lipon is extremely resistant to fracture, compared to other inorganic solid electrolytes [3].[1] Porz, T. Swamy, B.W. Sheldon, D. Rettenwander, T. Fromling, H.L. Thaman, S. Berendts, R. Uecker, W.C. Carter, Y.-M. Chiang, Mechanism of lithium metal penetration through inorganic solid electrolytes. Adv. Energy Mater. 7, 1701003 (2017)[2] Sellappan, T. Rouxel, F. Celarie, E. Becker, P. Houizot, R. Conradt, Composition dependence of indentation deformation and indentation cracking in glass. Acta Mater. 61, 5949–5965 (2013)[3] Kalnaus, A. Westover, M. Kornbluth, E.J. Herbert, N.J. Dudney, Resistance to fracture in the glassy solid electrolyte Lipon. J. Mater. Research, 36, 787-795 (2021)

Study and Optimization of the Formation Step of Next Generation Li-Ion Cells Using Design of Experiments (DOE) Methodology

The importance of the formation step in the Li-ion cell assembly process is often underestimated both in terms of economic impact due to its elevated cost [1] (Left Figure 1, with more than one third of cell finishing cost), but also in terms of electrochemical performance influence mainly driven by the Solid-Electrolyte-Interphase (SEI) formation during this first charge of the Li-Ion cell after its activation by electrolyte [2].In this study concerning the optimization of the formation step, we will use the design of experiments (DOE) methodology as this approach is a powerful tool that allows evaluating the effect of numerous parameters (including their linear, quadratic or interaction terms) on selected responses of interest with a limited number of trials when the experimental resources (including testing time, number of cells...) are limited.The formation step is generally divided in several sub-steps that includes many parameters [3,4] with some of them illustrated on the right figure 1: different current densities during the successive constant current steps, the different temperatures associated for each of these sub-steps that can also be of different durations and/or associated with limitations in states of charge. Additionally, specific electrolyte additives maybe used to improve the efficiency and quality of the formation step especially to modify the chemistry of the SEI....In our case, we present here a first approach using a screening design that is a specific type of DOE particularly adapted when the number of factors is elevated. Screening designs especially allow precising the first order input factors on the selected responses of interest, in our case Initial Coulombic Effciciency (ICE), resistance, discharge capacity; cyclability...The experimental data are generated thanks to the use of industrial dry (i.e. unactivated) NMC532/Graphite pouch-cells of 0.435 Ah. These dry cells allowed us including electrolyte factors in the DOE. Considering 8 different factors, a total of 17 trials were defined in the DOE that was set with MINITAB software. The full analysis of the DOE will be presented with the main effects for each response combined with the Pareto diagrams. These results will give general trends to define better conditions for the formation step and improve the cell performances.In a next step, we plan to pursue this approach with a surface response design on the selected first order factors, to enable a quantification of the performances and an optimization of the formation step. The study will also be completed by post-mortem analysis such as XPS studies to better correlate the formation step parameters with the SEI characteristics (chemistry, thickness...). Boston Consulting Report (2018). E Peled, S. Menkin. SEI: Past, Present and Future. Electrochem. Soc. 164 (7), 2017, A1703-C. Chiang, M.-S. Wu, J.-C. Lin. A Novel Dual-Current Formation Process for Advanced Lithium-Ion Batteries. Electrochem. Solid State Letters 8 (8), 2005, A423S. Zhang, K. Xu, T. R. Jow. Optimization of the Forming Conditions of the Solid-State Interface in the Li-Ion Batteries. J. Power Sources 130 (1-2) 2004, 281–285 Figure 1

(Invited) Advanced Electrode Processing for Next Generation Batteries

The development of environmentally friendly processing techniques is a key requisite for future sustainable battery development. The so-called DRYtraec® process is a solvent-free process developed as a viable approach to replace slurry-based binders by fibrous polymers and produce laminated electrodes with a low carbon footprint. It has been demonstrated to work for both, liquid and solid electrolyte batteries. NMC cathodes can be produced in a wide range of loading. For lithium sulfur batteries carbon/sulfur composites can be processed without sulfur loss. In particular in the field of solid state batteries it shows significant advantages. All-solid-state lithium-ion batteries are promising candidates to overcome safety and energy limitations of established lithium-ion batteries (LIBs). Excellent results have been reported for sulfide based electrolytes on a small scale. More and more companies announce their first pilot production lines. Therefore, scalable concepts for material and component development are of crucial need. We evaluate this process for the fabrication of thin argyrodite separator films and compare it with slurry-based separators in ASSBs. To test new cell concepts and components under relevant conditions, it is important to manufacture prototype cells with thin separator layers and flexible housing. Therefore, we prepared slurry-free pouch cells based on Ni-rich NMC cathodes and PVD-synthesized Si anodes.The presentation highlights recent developments of the DRYtraec® process and its application to ASSBs, LiS and LIBs.

(Invited) Tuning Selective CO2 Electrohydrogenation Under Mid Temperature and Pressure

To address rising environmental concerns and energy challenges, it is highly desirable to develop green technologies for a sustainable future. Hydrogenation reactions are essential processes in the chemical industry, giving access to a variety of valuable compounds. Electrochemical CO2 hydrogenation using renewable electricity is considered one of the most promising pathways to reach the environmental economics. Among various electrochemical devices, a solid state electrolyzer working at intermediate temperatures has the advantages of high reaction rates and low overpotentials. As CO2 molecules is quite stable, it is critical to develop electrocatalysts with high activity to reduce electricity engagement. Also, CO2 hydrogenation has multiple pathways which normally results in low selectivity for a target product. A tunable electrocatalyst with high selectivity to different products is desirable for CO2 conversion reactions. Heterostructured nanomaterials attracts great attentions in electrochemical systems. With careful design, they can show very high activity and selectivity towards an electrochemical reaction pathway. In this work, we combine theoretical simulations, including density functional theory (DFT) and ab initio molecular dynamics (AIMD) calculations, with experimental methods (characterizations and electrochemical measurements) for rational design of highly efficient heterostructured nanomaterials for CO2 hydrogenations. We studied the strong metal-support interaction (SMSI) in a doped CeO2 supported noble metal nanoparticles (NPs) system using theoretical calculations. The results indicate that SMSI largely depends on chemical conditions of the support and particle size of dispersed metal NPs. By tuning the SMSI, we can successfully change the catalytic activity and selectivity towards CO2 hydrogenation reactions. Based on these findings, we designed tunable heterostructured nanomaterials for efficient hydrogenation reactions at intermediate temperatures. These predictions were further confirmed by experimental method. By using a combination of high-throughput theoretical calculations and electrochemical measurements, we successfully developed highly active catalysts for electrochemical CO2 hydrogenation reactions. This framework is also applicable to other electrochemical systems using heterostructured materials.

KxFeO2 As Electrode Material for K-Ion Batteries

To meet future energy demands, developing beyond-lithium energy storage technologies have become a major part of global research activities. Potassium-ion batteries (KIBs) represent a promising technology thanks to their chemical and economic advantages1–3. The majority of the work on layered transition oxide was done on the KxMnO2 family4,5 due to their safety and price advantage.Interestingly, KFeO2 structure is not a layered structure as for LiFeO2 or NaFeO2; this structure is defined as FeO4 tetrahedral linked by their corners. In electrochemistry, a reversible capacity of 60 mAh/g (for 0.3K+) was delivers6.In our presentation, we will detail the electrochemical behaviour of KFeO2 and discuss the structure/properties relationship of this family of materials, showing the interest in the exploration of such a system. Xu, Y. et al. 2023 roadmap for potassium-ion batteries. J. Phys. Energy 5, 021502 (2023).Tian, Y. et al. Promises and Challenges of Next-Generation “Beyond Li-ion” Batteries for Electric Vehicles and Grid Decarbonization. Chem. Rev. 121, 1623–1669 (2021).Zhang, W., Liu, Y. & Guo, Z. Approaching high-performance potassium-ion batteries via advanced design strategies and engineering. Sci. Adv. 5, eaav7412 (2019).Kim, H. et al. Investigation of Potassium Storage in Layered P3-Type K0.5MnO2 Cathode. Adv. Mater. 29, 1702480 (2017).Liu, C., Luo, S., Huang, H., Zhai, Y. & Wang, Z. Layered potassium-deficient P2- and P3-type cathode materials KxMnO2 for K-ion batteries. Chem. Eng. J. 356, 53–59 (2019).Han, S. C., Park, W. B., Sohn, K.-S. & Pyo, M. KFeO2 with corner-shared FeO4 frameworks as a new type of cathode material in potassium-ion batteries. J. Solid State Electrochem. 23, 3135–3143 (2019).

Disruptive Semi-Solid Lithium Sulfur Battery Cell Design with Fully Separated Anolyte and Catholyte

Lithium-Sulfur-Batteries (LSBs) have been discussed as one of the most promising post-lithium-ion-battery technologies in literature for the last decade due to their high theoretical specific energy of 2600 Wh/kg. However, several drawbacks still exist in case of liquid LSB-concepts, especially cycling stability with low electrolyte excess in combination with a reasonable sulfur utilization plus cycle stability still hinders the commercial breakthrough of this battery technology. One main reason for both issues is the dissolution of the active material, sulfur, as polysulfides in the electrolyte, which leads to the so-called polysulfide shuttle that comprises polysulfide diffusion through the cell to the lithium metal anode resulting in decomposition reactions, and therefore, loss of active material. Several electrolyte approaches in order to limit polysulfide dissolution have been developed over the last 5-10 years, however, those electrolyte formulations usually lead to a strong lithium metal corrosion. Electrolytes that enable stable cycling of lithium metal batteries in combination with a nickel manganese cobalt oxide cathode have been successfully developed, however, they are ususally not compatible with the polysulfides of Li-S batteries. Hence, decoupling the anolyte from the catholyte has been much desirable. Recently introduced solid-state lithium sulfur batteries based on sulfidic solid electrolytes might overcome some challenges of conventional liquid LSBs since no formation or diffusion of polysulfide species can take place, and very high sulfur utilization have been already reached. However, solid-state LSBs have not been cycleable so far when a thin layer of solid electrolyte and lithium metal anode (without indium) were employed, especially in pouch cells, due to the formation of lithium dendrites, resulting in short circuits.Herein, a completely new battery design, a “semi-solid”-LSB, is presented. The concept combines the advantages of liquid and solid state LSBs. On the cathode side, an electrode comprising carbon, sulfur and sulfidic solid electrolyte (argyrodite) enables a solid to solid conversion of sulfur resulting in a complete suppression of the polysulfide shuttle.On the anode side, a liquid electrolyte enabling stable cycling of a lithium metal anode is employed. A careful design of the liquid electrolyte is crucial in order to obtain high stability of the liquid electrolyte against the lithium metal anode as well as to avoid side reaction between the solid electrolyte of the cathode and the liquid electrolyte. Different electrolytes are discussed for the new cell design and proof of concept was successfully reached in coin cells leading to 100 cycles with a stable coulombic efficiency of over 99 % which outperforms the majority of previously published Li-S cycling data. In addition, the concept was also transferred into first semi-solid lithium sulfur-pouch cells which is an important step in the direction of practical applications.

(Invited) Nitrogen Based Solid State Magneto-Ionics

Solid-state magneto-ionic (MI) effects have shown promise for energy-efficient nanoelectronics, where ionic migration may be used to achieve atomic-scale control of interfaces in magnetic nanostructures. To date, magneto-ionics have been mostly explored in oxygen-based systems [1-4], while there is a surge of interest in alternative ionic systems due to their different ionic migration mechanisms and characteristics [5-7].We have recently demonstrated effective MI control of magnetic functionalities using a variety of ionic species, particularly nitrogen. In nitride-based Ta/CoFe/MnN/Ta films, the chemically induced MI effect is combined with the electric field driving of nitrogen to electrically manipulate exchange bias [8]. Upon field-cooling the heterostructure, ionic diffusion of nitrogen from MnN into the Ta layers occurs. A significant exchange bias is observed, which can be further enhanced by ~ 20% after voltage conditioning (Figs. 1a-1e). This enhancement can be reversed by voltage conditioning with an opposite polarity. Nitrogen migration within the MnN layer and into the Ta capping layer causes the enhancement in exchange bias, which is observed in polarized neutron reflectometry studies.We have also achieved all-nitride-based magneto-ionic systems [9]. Thin films of (001)-ordered Mn4N are grown by sputtering Mn onto Mn3N2 seed layer on Si (100) substrate. Nitrogen ion migration across the Mn3N2 /Mn layers leads to a continuous evolution of the layers to Mn3N2 /Mn4N, Mn2N/Mn4N, and eventually Mn4N alone (Figs. 1f-1g). Furthermore, we have demonstrated MI control of the exchange bias effect in an all-nitride Mn4N/MnNx system, where the field-trained exchange field can be varied up to ten times by introducing or extracting nitrogen from the nitride system. This is achieved by adjusting the nitrogen gas partial pressure during deposition or varying annealing temperature after deposition.These effects demonstrate contrasts with oxygen-based MI effects in terms of operating principles, switching speed, and reversibility. Such MI systems are valuable platforms to gain quantitative understanding at buried interfaces. They also offer potentials for device applications based on electric modulation of magnetic functionalities.This work has been supported in part by the NSF (ECCS-2151809, DMR-2005108, DMR-1828420), SRC/NIST SMART Center, and KAUST.[1] U. Bauer et al., Nat. Mater. 14, 174 (2015).[2] C. Bi et al., Phys. Rev. Lett. 113, 267202 (2014).[3] D. A. Gilbert et al., Nat. Commun. 7, 11050 (2016).[4] G. Chen et al., Sci. Adv. 6, eaba4924 (2020).[5] A. J. Tan et al., Nat. Mater. 18, 35 (2019).[6] G. Chen et al., Phys. Rev. X 11, 021015 (2021).[7] J. de Rojas et al., Nat. Commun. 11, 5871 (2020).[8] C. J. Jensen et al., ACS Nano 17, 6745 (2023).[9] Z. J. Chen et al., Appl. Phys. Lett. 123, 082403 (2023). Figure 1

Bridging Technology and Environment: Sustainable Approaches in Semiconductor Chemical Mechanical Planarization (CMP)

As semiconductor technologies continue to advance in areas such as autonomous driving, artificial intelligence, 5G communications, the Internet of Things, and large-scale data processing, the demand for a reliable semiconductor industry is on the rise.(1) This growing demand necessitates the use of advanced device architectures, which heavily rely on two crucial processes: Chemical Mechanical Planarization (CMP) and post-CMP cleaning.(2) This talk will focus on the development of CMP slurries and post-CMP cleaning solutions, emphasizing their vital roles in these processes. We will delve into the comprehensive development of CMP slurries and post-CMP cleaning solutions, highlighting how synthesis methods can significantly affect the surface chemistry of ceria abrasives and impact the removal rates of SiO2 surfaces during STI CMP.(3, 4) Our research also demonstrates how our cleaning solutions can effectively remove even the most 10 nm-sized ceria particles from SiO2 surfaces,(5) thereby enhancing process efficiency. Furthermore, we will discuss the use of aliphatic amino acids as environmentally friendly corrosion inhibitors in CMP slurries, offering a sustainable alternative to the traditionally used benzotriazole (BTA) and addressing key environmental challenges.(6) In the context of the rapidly expanding semiconductor industry, it becomes critical to address global sustainability concerns and environmental health and safety (EHS) objectives. Our research proposes a comprehensive methodology for evaluating the sustainability of CMP consumables in semiconductor manufacturing, with a primary focus on CMP slurries due to their significant market share and shorter usage lifetimes. This research serves as a foundation for future CMP sustainability analyses, encouraging self-correction strategies within the CMP community to reduce environmental impact. We will also introduce a robust framework for the Life Cycle Assessment (LCA) of CMP consumables, marking a crucial step toward achieving these sustainability goals. In summary, this talk will explore the intricate details of CMP and post-CMP processes, their pivotal roles in the advancement of semiconductor manufacturing, and the imperative task of aligning these processes with environmental and sustainability objectives.This talk is dedicated to the special session in honor of Prof. Babu. S. Babu, Advances in Chemical Mechanical Planarization (CMP), Woodhead Publishing (2021).J. Seo, Journal of Materials Research, 36, 235 (2021).J. Seo, J. W. Lee, J. Moon, W. Sigmund and U. Paik, ACS applied materials & interfaces, 6, 7388 (2014).J. Seo, J. H. Kim, M. Lee, J. Moon, D. K. Yi and U. Paik, Journal of colloid and interface science, 483, 177 (2016).J. Seo, A. Gowda and S. Babu, ECS Journal of Solid State Science and Technology, 7, P243 (2018).H. T. T. Tran, J. Gichovi, E. J. Podlaha and J. Seo, in Electrochemical Society Meeting s 243, p. 1809 (2023).

Strategy to Enhance Air Electrode Performance and Durability in Soe and Co-Soe Modes: Composite Electrode with a Gradually Changing Composition

Among the key challenges of the Solid Oxide Cell (SOC) is stable, long-term operation in electrolysis (SOE, Solid Oxide Electrolysis), and co-electrolysis (co-SOE) modes. Many factors impact the SOC’s lifespan, i.e., the chemical composition of the fuel and air electrode, the type of the cell, and working conditions (e.g., current density, temperature). Therefore, the development of high-performance and durable cells seems to be crucial, as SOE/co-SOE systems may play an important role in the ongoing transformation toward a climate-neutral economy (low-emission hydrogen production; efficient utilization of CO2and renewable energy) [1,2].One of the crucial degradation mechanisms of SOC in electrolysis/co-electrolysis mode is the delamination of the air electrode, caused by the accumulation of high oxygen partial pressure on the interphase of the electrolyte, the formation of additional phases, and/or reaction of voids/cracks in the electrolyte or buffer layer [2,3]. A strategy to mitigate the risk of air electrode delamination is to use composite electrode based on the buffer layer material (GDC- Gd0,1Ce0,9O2) and state-of-the-art electrode – LSC (La0,6Sr0,4CoO3-δ), as it will lower the effect of the thermal expansion mismatch between the electrode and buffer layer/electrolyte. Moreover, by manipulating the microstructure of the electrode, e.g., by introducing a pore-forming agent, it is possible to ensure fast and effective collection of oxygen generated during operation in the SOE/co-SOE mode on the air side (preventing potential differences leading to the stresses on the electrode-electrolyte interface).In this study, the electrochemical performance of solid oxide cells with a modified, gradually changing composite LSC-GDC air electrode was verified in electrolysis and co-electrolysis modes. The following air electrode compositions were proposed for cell preparation: type 1: 1st layer 50LSC:50CGO, 2nd layer: 75LSC: 25GDC, 3rd layer: LSC, type 2: 1st layer 75LSC:25CGO, 2nd and 3rd layers: LSC with PMMA as a pore former; type 3: 1st layer 75LSC:25CGO, 2nd and 3rd layers: 90LSC:10GDC, and type 4: 1st layer 85LSC:15CGO, 2nd layer: 90LSC:10GDC; 3rd layer: LSC with PMMA as a pore former. The proposed air electrode was tested at the single-cell level (cells size of 50 mm x 50 mm), and the most promising solutions were implemented in the SOC stack (a stack consisting of 3-5 cells with a size of 110 mm x 110 mm). The electrochemical analysis of the developed cells includes measurements of the j-V dependences and EIS spectra under different modes (SOE and co-SOE), various temperatures, current densities, and different gas flows delivered at the air side of the cell. The microstructure, morphology, and composition of the prepared cells and samples after testing were analyzed using SEM, SEM-EDS, and, for selected samples, the FIB-SEM method. The obtained results showed that by a gradually changing the electrode composition, specifically by reducing the GDC content in the electrode, it is possible to obtain a stable electrode (a strategy to prevent air electrode delamination) with high catalytic activity in both electrolysis and co-electrolysis modes. The composite GDC-LSC electrodes with various compositions seem to be promising air electrodes for SOE and co-SOE systems. The study achieves relatively high current densities compared to the SoA cells, with only negligible degradation changes observed after long-term testing (>300 h in single cell configuration). Acknowledgments The presented research was financially supported by: the National Centre for Research and Development, Poland, within project no. LIDER/1/0003/L-12/20/NCBR/2021, which focuses on research related to composite electrodes. Anna Niemczyk acknowledges support from the Foundation for Polish Science (FNP) through a scholarship from the START program. References B. Mogensen et al., Clean Energy 3 (2019) 175; DOI: 10.1093/ce/zkz023Hauch, P. Blennow, Solid State Ionics 391 (2023) 116127; DOI: 10.1016/j.ssi.2022.116127Subotić, C. Hochenauer, Progress in Energy and Combustion Science 93 (2022) 101011; DOI: 10.1016/j.pecs.2022.101011

(Invited) S. R. Narayan and the Electrochemistry Scene at the Institute of Science

The late Prof. S. R. Narayan was trained at the prestigious Indian Institute of Science in Bangalore, India. This author had the fortune of also receiving his Ph.D. degree from the same institution, albeit not quite in the area of electrochemistry but in a closely allied topic, namely, solid state chemistry. This author also did not overlap with the symposium honoree but was quite familiar with the infrastructure and faculty that existed in the department at the time Prof. Narayn graduated. The home department went by the acronym "IPC" and stood for Inorganic and Physical Chemistry. This talk will first summarize the electrochemistry division in that department and the R&D activities in progress in the 1970s and 80s. Then my talk will briefly address the areas where my own research overlapped with Prof. Narayan's research interests in the area of fuel cells. The talk will conclude with some personal recollections and reminiscences of this very fine gentleman and electrochemist.

Ontology Creation and Database Implementation for Lab-Scale Solid-State Battery Cells

New developments and publications on alkali metal solid-state batteries are being published at a high rate, with the total number of publications now in the thousands, but the search and analysis of the data in these publications is still largely done using key words and through careful reading of the article and the supporting information. The challenges of efficiently searching and extracting data from thousands of publications in a field are also present in other fields, such as perovskite solar cells, for which a large (>15,000) set of cell data has been entered into a database that continues to be updated.1 A database for alkali metal (e.g., based on Na+ and Li+ conduction) solid-state cells that could be easily searched and that facilitated advanced forms of data analysis could accelerate research progress, and is consistent with efforts such as definition of the “Principles of the Battery Data Genome” and the BIG-MAP project.2 In this talk, we describe our approach to creating an ontology and database for lab-scale solid-state cells, along with results to date. Key areas for the ontology include component material identities, material properties, component properties (e.g., active material loading, mass fractions, thicknesses), processing conditions for materials and the cell itself (e.g., ball milling time, sintering time), and both performance (e.g., rate capability) and degradation (e.g., cycle life). Results based on several hundred solid state cells in our database are presented in terms of histogram plots, violin plots, correlation plots, and other representations. We also describe our efforts to integrate our ontology and tool with broader efforts in the field, and to make it broadly useful to battery researchers.1. Nature Energy, volume 7, pages 107–115 (2022) and https://www.perovskitedatabase.com/2. Joule 6, 2253–2271, October 19, 2022 and https://www.big-map.eu/dissemination/battinfo

Dynamic Coupling of Internal Strain Field and Lithium Pathway within Individual Battery Particles in Solid State Batteries

In all-solid-state batteries (ASSBs), (electro)chemo-mechanical aspects such as uneven interfaces, cathode-electrolyte interphase formation, delamination, fracture, defects, etc., are the major factors in capacity fade but remain largely unknown.Nonhomogeneous transfer of lithium ions can cause significant variations in strain and stress within battery electrodes, leading to degradation in battery performance. In all-solid-state batteries (ASSBs), the lithium pathway and the associated strain/stress field become more intricate due to the (electro)chemo-mechanical reaction at the electrode-electrolyte interfaces. The dynamic volume change in active particles are heavily influencing by strength of the solid electrolyte and interfacial conformality. This can continually alter the lithium pathway and the internal stress field, leading to recurrent redefinitions of (electro)chemo-mechanical environment.Here, we have developed an operando coherent X-ray imaging platform and associated analysis methodologies. This technology can track the nanoscale transport of lithium and the strain evolution of individual electrode particles in ASSBs. With this platform, we gained a comprehensive electrochemical and mechanical understanding of the cycling properties of single electrode particles in ASSBs.

Ion Conductive High Li+ Transference Number Polymer Composites for Solid-State Batteries

Solid-state electrolytes are a promising field of study to improve the safety and energy density of lithium-based batteries. Composite solid electrolytes seek to leverage both the desirable mechanical properties of polymers and the high conductivity of active ceramic fillers; however, Li+ transport through the composite, and especially the extent of Li+ through the ceramic phase, remains an open question.1, 2 Simulations suggest that decreasing interfacial resistance between polymer and ceramic would promote transport through ceramic particles.1 Our work seeks to improve Li+ transport in the ceramic phase by engineering both polymer and ceramic materials that minimize the interfacial resistance between the two.Traditional polymer electrolytes have a low transference number (~0.15) compared to ceramics (~1), and when combined in composites this mismatch has been suggested as a major contributor to interfacial impedance.3 We explore the effect of the transference number mismatch by using a single-ion conducting polymer poly((trifluoromethane)sulfonamide lithium methacrylate) (PMTFSILi). The Li+ transport in a composite electrolyte with high transference number PMTFSILi is compared with that of a system utilizing a lithium salt.Contaminants on ceramic surface can also contribute to interfacial resistance. We consider how lithium carbonate (Li2CO3) content on the surface of LLZTO (Li6.4La3Zr2Ta0.6O12) affects Li+ transport. Accompanying this study is a detailed description of washing procedures used to clean the LLZTO surface. Titration Mass Spectrometry (TiMS) is used to quantify Li2CO3 content in our ceramic particles and assess the effectiveness of our cleaning procedures. Inductively-coupled plasma mass spectrometry (ICP-MS) data also assists in measuring the impact (Li+ exchange and transition metal dissolution) of various washing procedures (basic, acidic) on the LLZTO particles.Solid-state NMR has proven to be a useful tool in deconvoluting Li+ transport in different phases of composite electrolytes2 and is the primary technique we use to quantify transport in our system. These findings will provide a deeper understanding into the relationship between interfacial resistance and Li+ transport in composite electrolyte systems and shed light on how material choices can better utilize the highly conductive ceramic phase for Li+ transport. Kim, HK., Barai, P., Chavan, K. et al.Transport and mechanical behavior in PEO-LLZO composite electrolytes. J Solid State Electrochem 26, 2059–2075 (2022). https://doi.org/10.1007/s10008-022-05231-wZheng J., Hu, Y. New Insights into the Compositional Dependence of Li-Ion transport in polymer-ceramic composite electrolytes. ACS Appl. Mater. Interfaces, 10, 4, 4113–4120 (2018). https://doi.org/10.1021/acsami.7b17301Mehrotra A. et al. Quantifying Polarization Losses in an Organic Liquid Electrolyte/Single Ion Conductor Interface. Electrochem. Soc. 161 A1681 (2014). https://doi.org /10.1149/2.0721410jes

(Invited) Role of Oxidant Gas for Atomic Layer Deposition of HfxZr1−XO2 Thin Films on Ferroelectricity of Metal-Ferroelectric-Metal Capacitors

Since the first report of ferroelectricity in HfxZr1−xO2 (HZO) in 2011 [1], a lot of attention has been devoted for future non-volatile memory device applications due to its scalability (< 10 nm), low thermal budget (< 400°C) and matured atomic layer deposition (ALD) technique [2]. The thermal ALD process using H2O or O3 is generally employed for the fabrication of ferroelectric HZO thin films. On the other hand, the effect of the plasma-enhanced ALD process using O2 plasma gas on the crystallinity and ferroelectricity has not been systematically clarified. In this paper, we report the importance of ALD oxidant gases for HZO films using H2O or O2 plasma on the ferroelectricity of metal–ferroelectric–metal (MFM) capacitors.MFM capacitors with the H2O- and O2 plasma-based HZO films were fabricated as follows. A 10-nm-thick HZO films were deposited on a TiN bottom-electrode (BE-TiN) by ALD at 300°C using H2O or O2 plasma as oxidant gases and (Hf/Zr)[N(C2H5)CH3]4 (Hf:Zr = 1:1) cocktail precursor. The Hf/Zr ratios in both types of HZO films were estimated to be 0.4/0.6 using X-ray photoelectron spectroscopy (XPS). Next, a post-deposition annealing (PDA) process was carried out at 400 °C for 1 min under a N2 atmosphere. Finally, a TiN top-electrode was deposited by DC sputtering.First, the crystallinity and remanent polarization (2P r = P r + − P r −) of the H2O- and O2 plasma-based HZO films were investigated. Nanocrystals with ferroelectric orthorhombic (O), tetragonal (T), cubic (C) phases partially existed in the O2 plasma-based film after the ALD process, while an amorphous structure dominantly existed in the H2O-based film, analyzed by the grazing-incidence X-ray diffraction analysis and cross-sectional transmission electron microscopy images [3]. This could be because of a strong oxidation power and high energy ion/electron bombardment of O2 plasma. After the PDA process, the O phase was formed more in the O2 plasma-based HZO film than the H2O-based film. Therefore, the nanocrystal grains in the as-grown O2 plasma-based HZO film could play an important role as nuclei for the crystallization and formation of O phase [3,4]. From the polarization–electric field hysteresis curves, the PDA-treated O2 plasma-based capacitor exhibited 2P r of 20 µC/cm2, which was 1.5 times higher than that (13 µC/cm2) of the H2O-based capacitor. Thus, these results indicate that the crystallization and O phase formation of HZO films were promoted by using O2 plasma gas as an ALD oxidant, resulted in a higher 2P r.Next, endurance properties of these MFM capacitors were evaluated. In the wake-up state, both capacitors showed almost the same increase rate (~8%) of switching polarization (P sw). In the fatigued state, on the other hand, the O2 plasma-based capacitor exhibited less P sw degradation (~33%) after 106 cycles, whereas the P sw of H2O-based capacitor decreased by ~47%. To clarify these different fatigue properties, the TiOxNy interface reaction layer (IRL) formation at the HZO/BE-TiN interface was analyzed using synchrotron hard X-ray photoelectron spectroscopy (HAXPES). For the HAXPES Ti 2p spectra, the Ti-O peak intensity for the O2 plasma-based capacitor was larger than that of the H2O-based capacitor [5]. Therefore, an oxygen-rich TiON-IRL could be formed at the HZO/BE-TiN interface during ALD process due to the stronger oxidizing power of O2 plasma. Additional oxygen vacancies (VO) were reported to formed in HfO2-based films during field cycling due to the interface reaction between the HfO2-based film and TiN electrode. Moreover, one of the origins of the P sw degradation was thought to be domain pinning caused by VO [6]. Therefore, an oxygen-rich TiON-IRL for the MFM capacitor with the O2 plasma-based HZO film could prevent the interface reaction and formation of additional VO in HZO films, led to superior fatigue properties.In summary, the MFM capacitor with the O2 plasma-based HZO film showed superior 2Pr and fatigue resistance compared to those of the H2O-based one. Based on these experimental results, it is important to consider the selection of an ALD oxidant for fabrication of HZO-based MFM capacitors.This work was partly supported by JSPS KAKENHI (Nos. JP21J01667, JP20H02189, and JP18J22998) and MEXT Leading Initiative for Excellent Young Researchers (No. JPMXS0320220213). The HAXPES measurements were performed under approval of the NIMS Synchrotron X-ray Station (2020A4602 and 2020A4651).[1] J. Müller et al., Appl. Phys. Lett. 99, 112901 (2011).[2] J.-H. Kim et al., ACS Appl. Electron. Mater. 5, 4726 (2023).[3] T. Onaya et al., APL Mater. 10, 051110 (2022).[4] T. Onaya et al., Microelectron. Eng. 215, 111013 (2019).[5] T. Onaya et al., Solid State Electron. 210, 108801 (2023).[6] M. Pešić et al., Adv. Funct. Mater. 26, 4601 (2016).