Li-ion Battery Applications Research Articles

Effect of Li6.4La3Zr1.4Ta0.6O12 Fillers on the Interfacial Properties between Composite PEO-LiTFSI Electrolytes with Li Metal during Cycling.

PEO-LiX solid polymer electrolyte (SPE) with the addition of Li6.4La3Zr1.4Ta0.6O12 (LLZTO) fillers is considered as a promising solid-state electrolyte for solid-state Li-ion batteries. However, the developments of the SPE have caused additional challenges, such as poor contact interface and SPE/Li interface stability during cycling, which always lead to potentially catastrophic battery failure. The main problem is that the real impact of LLZTO fillers on the interfacial properties between SPE and Li metal is still unclear. Herein, we combined the electrochemical measurement and in situ synchrotron-based X-ray absorption near-edge structure (XANES) imaging technology to study the role of LLZTO fillers in directing SPE/Li interface electrochemical performance. In situ XRF-XANES mapping during cycling showed that addition of an appropriate amount of LLZTO fillers (50 wt %) can improve the interfacial contact and stability between SPE and Li metal without reacting with the PEO and Li salts. Additionally, it also demonstrated the beneficial effect of LLZTO particles for suppressing the interface reactions between the Li metal and PEO-LiTFSI SPE and further inhibiting Li-metal dendrite growth. The Li|LiFePO4 batteries deliver long cycling for over 700 cycles with a low-capacity fade rate of 0.08% per cycle at a rate of 0.3C, revealing tremendous potential in promoting the large-scale application of future solid-state Li-ion batteries.

First-Principles Studies on Transition Metal Doped Mo2B2 as Anode Material for Li-Ion Batteries.

New two-dimensional (2D) transition-metal borides have attracted considerable interest in research on electrode materials for Li-ion batteries (LIBs) owing to their promising properties. In this study, 2D molybdenum boride (Mo2B2) with and without transition metal (TM, TM=Mn, Fe, Co, Ni, Ru, and Pt) atom doping was investigated. Our results indicated that all TM-doped Mo2B2 samples exhibited excellent electronic conductivity, similar to the intrinsic 2D Mo2B2 metal behavior, which is highly beneficial for application in LIBs. Moreover, we found that the diffusion energy barriers of Li along paths 1 and 2 for all TM-doped Mo2B2 samples are smaller than 0.30 and 0.24 eV of the pristine Mo2B2. In particular, for 2D Co-doped Mo2B2, the diffusion energy barriers of Li along paths 1 and 2 are reduced to 0.14 and 0.11 eV, respectively, making them the lowest Li diffusion barriers in both paths 1 and 2. This indicates that TM doping can improve the electrochemical performance of 2D Mo2B2 and that Co-doped Mo2B2 is a promising electrode material for LIBs. Our work not only identifies electrode materials with promising electrochemical performance but also provides guidance for the design of high-performance electrode materials for LIBs.

Understanding the catalysis of chromium trioxide added magnesium hydride for hydrogen storage and Li ion battery applications

This study explores how the chemical interaction between magnesium hydride (MgH2) and the additive CrO3 influences the hydrogen/lithium storage characteristics of MgH2. We have observed that a 5 wt.% CrO3 additive reduces the dehydrogenation activation energy of MgH2 by 68 kJ/mol and lowers the required dehydrogenation temperature by 80 °C. CrO3 added MgH2 was also tested as an anode in an Li ion battery, and it is possible to deliver over 90% of the total theoretical capacity (2038 mAh/g). Evidence for improved reversibility in the battery reaction is found only after the incorporation of additives with MgH2. In depth characterization study by X-ray diffraction (XRD) technique provides convincing evidence that the CrO3 additive interacts with MgH2 and produces Cr / MgO byproducts. Gibbs free energy analyses confirm the thermodynamic feasibility of conversion from MgH2/CrO3 to MgO/Cr, which is well supported by the identification of Cr(0) in the powder by X ray photoelectron spectroscopy (XPS) technique. Through high resolution transmission electron microscopy (HRTEM) and energy dispersive spectroscopy (EDS) we found evidence for the presence of 5 nm size Cr nanocrystals on the surface of MgO rock salt nanoparticles. There is also convincing ground to consider that MgO rock salt accommodates Cr in the lattice. These observations support the argument that creation of active metal – metal dissolved rock salt oxide interface may be vital for improving the reactivity of MgH2, both for the improved storage of hydrogen and lithium.

Study of Ge-doped garnet type Li7La3Zr2O12 as solid electrolyte for Li-ion battery application

Study of Ge-doped garnet type Li7La3Zr2O12 as solid electrolyte for Li-ion battery application

Effective Cu-Fe oxide/ multidimensional nanocarbon-coupled ternary composite-based anode: Mechanistic insight into interface tuning for swift Li-ion diffusion

This work focused on engineering the hybrid nanocomposite-based anode comprising CuFe2O4 (CFO), reduced graphene oxide (RG), and functionalized carbon nanotubes (FC) to investigate its Li-ion storage kinetics. The ternary nanocomposites CFO/RG/FC (CFO-C) demonstrated a specific capacity (SC) of 760 mAh/g at a Cdensity of 200 mA/g after 100 electrochemical charge-discharge cycles and an SC of 450 mAh/g at a high Cdensity of 500 mA/g after 300 electrochemical cycles. Results revealed that the addition of RG and FC aided in enhancing the electrical transport at the interface, in turn, it assisted in augmenting the Li-ion storage capability from ∼240 to ∼760 mAh/g at the end of 100 charge-discharge cycles with a Cdensity of 200 mA/g. RG and FC acted as anchoring sites for CFO and spacer, respectively, which resulted in improved electrical transport to accelerate Li-ion diffusion transport by fivefold. Such composite anode is a probable candidate as the high-performance anode in designing high-energy density Li-ion battery applications.

The effect of the pyrolysis temperature and biomass type on the biocarbons characteristics.

The conversion of biomass and natural wastes into carbon-based materials for various applications such as catalysts and energy-related materials is a fascinating and sustainable approach emerged during recent years. Precursor nature and characteristics are complex, hence, their effect on the properties of resulting materials is still unclear. In this work, we have investigated the effect of different precursors and pyrolysis temperature on the properties of produced carbon materials and their potential application as negative electrode materials in Li-ion batteries. Three biomasses, lignocellulosic brewery spent grain from a local brewery, catechol-rich lignin and tannins, were selected for investigations. We show that such end-product carbon characteristic as functional and elemental composition, porosity, specific surface area, defectiveness level, and morphology strictly depend on the precursor composition, chemical structure, and pyrolysis temperature. The electrochemical characteristics of produced carbon materials correlate with the characteristics of the produced materials. A higher pyrolysis temperature is shown to be favourable for production of carbon material for the Li-ion battery application in terms of both specific capacity and long-term cycling stability.

High Li-ion diffusion coefficient in LiMn1.5Ni0.5O4 thin films for all-solid Li-ion battery applications

Among various choices of high-performance cathode materials, Ni substituted LiMn2O4 spinel LiMn1.5Ni0.5O4 (LMNO) has proved to be one of the solutions to yield a high-performance and high-energy density material, which can operate at a higher potential window. This study explores the high diffusion coefficient and electrochemical performance at wide current rates of LMNO thin films with less than 50 nm thickness, fabricated on SrTiO3 and SS substrates by the pulsed laser deposition method. The LMNO film with less thickness and the performance without binder and conducting carbon widen the Li-ion path and decrease diffusion length, resulting a higher diffusion coefficient on the order of 10−5 to 10−6 cm2/s, which is several orders higher than the previously obtained reports for bulk counterpart. The cycling stability and rate capability at different current densities of LMNO thin film electrodes are further investigated. Charge–discharge profile at varying current rates of 5, 10, 15, 20, 25, 50, 75, 100, and 125 mA/cm2 is obtained for 500 cycles. The as fabricated film shows a stable profile for 500 cycles with 1.3 and 2.3 μA h/cm2 areal discharge capacity at 25 and 5 mA current rates, respectively. Electrode interfacial properties of LMNO film (before and after cycles) are analyzed using impedance technique. This study indicates that the LMNO thin films can be employed as a cathode layer for fabricating the all-solid thin film batteries for energy applications.

Electrochemical elucidation of phosphorus-doped and 3D graphene aerogel surface-modified SiOx porous nanocomposite electrode material for high-performance lithium-ion batteries

Silicon oxide (SiOx) is promising as an earth abundant eco-friendly cost-effective anode material for lithium-ion batteries (LIBs), boasts a higher capacity compared to commercial graphite, garnering significant interest. Nevertheless, its practical application is hindered by issues related to poor cycling performance and low electronic conductivity. In this investigation, graphene aerogel-wrapped (GA) red phosphorus (P) doped SiOx (P-SiOx@GA) composite material is successfully constructed through ball-milling followed by freeze-drying and thermal treatment processes. The prepared materials are characterized the physico-chemical properties. The electrochemical performance is evaluated through Li-ion half and full (LiFePO4//P-SiOx@GA) cells configuration. The synthesized P-SiOx@GA electrode exhibits outstanding cyclic performance, demonstrating a specific capacity of 1094 mAh g−1 at 0.5C with a capacity retention of 80.3 % over 200 cycles in half-cell test. Furthermore, it demonstrates superior rate capability and delivers a reversible rate capacity of 754 mAh g−1 at 2C. Besides, the Li-ion punch cell configuration of LiFePO4//P-SiOx@GA shows good reversible capacity of 1.4 mAh at 0.5C over 300 cycles. The doping of P and porous 3D structure of GA forms an SiOx matrix network is facilitate the establishment of a 3D conductive pathway for electron transport and Li+ diffusion but also acts as a flexible matrix to accommodate the volume changes of SiOx. Therefore, the results and way of preparation promotes a practical feasibility of high-performance Si-based Li-ion batteries applications.

Exploring the Potential of Lithium Metal Oxyfluoride, LiMOF, Compounds (M = Mn, Fe, Co, and Ni) for Advanced Li-Ion Battery Applications: A Comprehensive Ab Initio Investigation

Exploring the Potential of Lithium Metal Oxyfluoride, LiMOF, Compounds (M = Mn, Fe, Co, and Ni) for Advanced Li-Ion Battery Applications: A Comprehensive Ab Initio Investigation

Physicochemical activation of soap-nut seeds-derived hard carbon as a sustainable anode for lithium-ion batteries

This study explores the conversion of soap-nut seeds, a naturally abundant agricultural waste, into hard carbon, which can be used as a sustainable anode for applications in Li-ion batteries.

The Nb–Ti–W–O system as safe high-power anodes for Li-ion batteries

New materials are currently needed to serve as anodes in Li-ion batteries for applications that require extreme safety, long lifetimes, high power and improved energy density.

A new nanostructured γ-Li3PO4/GeO2 composite for all-solid-state Li-ion battery applications.

High-temperature sintering is crucial to achieve good crystallinity and fast-ion conduction in oxide-type solid-electrolytes such as lithium garnets, NASICONs and LISICONs, leading to stiff ceramics which are difficult to integrate in all-solid-state batteries. Developing conventional oxide-based solid-electrolytes in deformable forms that maintain good ion transport properties and allow facile formulation of bulk-type solid-state batteries, hence, remains a challenge. Here, a new γ-Li3PO4/GeO2 composite, that adopts a novel nanostructured architecture and retains deformability after calcination at 500 °C, is successfully synthesized and densified by cold-pressing. Cold-pressed pellets of the new composite showed an ion conductivity that is four orders of magnitude higher than that of the parent γ-Li3PO4 and comparable to those of high-temperature stiff Li3+xP1-xGexO4 ceramics. The γ-Li3PO4/GeO2 composite is stable against high voltages (up to 5 V vs Li+/Li), which suggests a safe use in contact with high-voltage cathodes. The new composite can also be modified to serve as an active anode layer in solid-state cells due to the electrochemical activity of GeO2 at low voltages (<1 V vs. Li+/Li). This study emphasizes the potential of using low-temperature synthesis to develop novel oxide-based nanoarchitectures for all-solid-state battery applications.

Utilization of Coal Fly-Ash derived Silicon (Si) as Capacity Enhancer of Li-Ion Batteries Anode Material

The increasing demand for energy has caused a rise in coal usage, resulting in high fly ash generation. The high SiO2, Al2O3, and Fe2O3 content in fly ashes (FAs) allow them to be processed in electrical energy storage technology, such as lithium-ion-based secondary batteries. The research aims to develop silicon from FAs for Li-ion battery applications. The fabrication of silicon materials employed in this study are (i) extraction of SiO2 from FA, (ii) gelation of SiO2, (iii) magnesiothermic reduction of SiO2 to Si under N2 flow, (iv) purification of silicon, (v) the solid-state composite fabrication of Si/C. The as-prepared Si was characterized. XRD test showed the presence of silicon phase and minor impurities in Mg. SEM analysis of the Si showed that the material has a polymorph shape with a rough surface of micron-sized secondary particles. EDX test showed the presence of impurities in the form of O and Mg atoms; meanwhile, the EDX mapping confirmed the dominant distribution of Si in the sample. Galvanostatic charge-discharge analysis of a battery with 5%Si/C anode and LiNi0.8Co0.1Mn0.1O2 or NCM811 cathode resulted in a specific charge and discharge capacity of 600 mAh/g and 473.6 mAh/g, respectively, which is greater than the graphite theoretical capacity of 372 mAh/g.

Exploring lithium salt solution in sulfone and ethyl acetate-based electrolytes for Li-ion battery applications: a molecular dynamics simulation study

The design of lithium-ion batteries (LIBs) by introducing novel electrolytes is an interesting research topic in electrochemistry, due to the necessity of using LIBs to fight against the energy crisis and environmental pollution.

High-power recycling: upcycling to the next generation of high-power anodes for Li-ion battery applications

Upcycling current high power electrodes (Li4Ti5O12) towards the next generation of titanium niobium oxide materials, while reclaiming a critical element: lithium.

One pot synthesis of polyoxometalate@polyaniline/MXene/CNTs quaternary composites with a 3D structure as efficient electrode materials for Li-ion batteries applications

Double transition metal carbides (MXenes) are considered promising candidates for a good electrode material because of their enormous specific surface area, metallic conductivity and hydrophilicity. However, their low capacity, easy oxidation and self-restacking restrict their large-scale application. In this paper, we selected Mo2TiC2Tx MXene as the conductive carrier of polyoxometalate (POM), carbon nanotubes (CNTs) as the linker to construct a novel POM@polyaniline (PANI)/Mo2TiC2Tx/CNTs quaternary composites (denoted as PPMC) with a unique 3D structure by using a facile one pot synthesis strategy. The PPMC with unique 3D structure as an anode material for LIBs exhibits superior lithium storage capacity (621 mAh g−1 at 0.1 A g−1) and promising cyclic stability (445 mAh g−1 after 1000 periods at 1.0 A g−1) and good rate capability. The enhanced performance is mainly attributed to the synergistic effect between components. Our work provides an effective strategy to improve the reversibility and cycling stability of electrode materials for LIBs, which will contribute some reference value to the development of high-performance MXene based electrode materials.

Synergistic Effect of Lithium (difluoromethanesulfonyl)(trifluoromethanesulfonyl)Imide (LiDFTFSI) and Vinylene Carbonate (VC) on High Performance of NMC811║Graphite Cells

Lithium-ion batteries (LIBs) have gained increasing importance in energy storage systems, driven by the growing demands of grid storage, automotive, and portable consumer applications. To meet the need for high energy density batteries, one promising approach involves the utilization of high capacity layered transition metal oxide cathodes, such as nickel-rich LiNi0.8Mn0.1Co0.1O2 (NMC811), which can deliver a high reversible specific capacity of over 180 mAh·g-1 [1,2]. However, due to the structural and interfacial instability[3], nickel-rich NMC cathode still faces challenges in long-term galvanostatic cycling. For these reasons, design of novel electrolyte formulations, which enable formation of an effective cathode electrolyte interphase (CEI), is highly desirable. Recent studies have highlighted the cross-talk between the cathode and anode, indicating that the evolution of the solid electrolyte interphase (SEI) can impact the formation of the CEI[4]. Thus, establishing an effective SEI/CEI pair is essential for achieving long-term cycling of nickel-rich NMC cathode-based cells. Electrolyte optimization plays a crucial role in facilitating the formation of a desirable SEI/CEI pair, leading to an improved cell performance and longevity. Lithium (difluoromethanesulfonyl)(trifluoro-methanesulfonyl)imide (LiDFTFSI) has proven to be promising in solid-polymer-electrolyte batteries due to the good SEI/CEI formation ability and suppressed Al-dissolution[5]. Additionally, LiDFTFSI exhibits also good compatibility with Li-metal batteries[6], heralding promising applications in Li-ion batteries. However, there is lack of systematic research investigating the potential impact of LiDFTFSI on the cathode as well as on resulting CEI formation and dynamics.In this work, we demonstrated enhanced galvanostatic cycling performance of NMC811||graphite cells achieved by utilizing LiDFTFSI and lithium hexafluorophosphate (LiPF6) in a blended salt organic carbonate-based electrolyte formulation. Comprehensive electrochemical and post mortem analysis revealed that the LiDFTFSI alone can effectively mitigate the structural changes in the NMC811 electrode by facilitating the formation of modified CEI. However, the continued growth of an inhomogeneous CEI, caused by the cross-talk effect between electrodes, adversely affected long-term cycling stability. To address this, vinylene carbonate (VC) was introduced to the electrolyte. Synergistic effect with LiDFTFSI leads to the formation of effective and uniform SEI and CEI. As a result, 720 charge/discharge cycles were achieved in NMC811||graphite cells with LiDFTFSI and VC containing electrolytes at 1C while maintaining 80% state-of-health (SOH80%).

Solvation Structure and Dynamics in Ionic Liquid Electrolytes with Hydrofluoroether for Li-Ion Batteries

The addition of hydrofluoroethers (HFEs) to Li-ion battery electrolytes reduces flammability and enhances the cycling behavior at a wider temperature range. In the case of ionic liquid electrolytes, where the ion concentration is high and Li+ solvation by anions govern the transport properties, HFEs facilitate the separation of ion aggregates. In this study, the addition of HFE to n-methyl-n-butylpyrrolidinium bis(trifluoromethanesulfonyl)imide [PYR14][TFSI] with Li-salts of lithium (nonafluorobutane)(trifluoromethanesulfonyl)imide [Li][IM14] and [Li][TFSI] (0 ≤ x Li ≤ 0.3), were studied to understand the compositional changes in phase, the liquid structure and the transport properties. A suppression in the melting point with the addition of HFE was accompanied with improved conductivities at lower temperatures. Li+ was found to primarily solvated by [TFSI] with some contribution by [IM14], as determined from Raman spectroscopy and molecular dynamics (MD) simulations. Further, HFE encouraged florous domain formations as determined by HOESY NMR and even short contacts between HFE and Li+ as a result of tighter anion-solvated Li+ without aggregation. Li+ diffusivity of 1.2610-12 m2/s at 0 °C and x Li = 0.2 was achieved with a high Li+ transference of 0.16, relative to ionic liquid electrolytes at 0 °C. The developed electrolytes demonstrated cyclable Si-Li half cells. This study demonstrates the tunability of ionic liquid electrolytes by asymmetric fluorinated anions and HFE co-solvents for low temperature Li-ion battery applications.

(Energy Technology Division Walter van Schalkwijk Award in Sustainable Energy Technology Address) Exploring New Electrode Designs with Nanofibers

In recent years, electrospinning has been gaining popularity as a robust and scalable technique for the fabrication of non-woven mats of sub-micron diameter polymer fibers. Although not as well studied, the technique can also be used to prepare particle/polymer fiber networks with high intra- and inter-fiber porosity. Such fibrous mats can be used as porous electrodes in fuel cells and batteries, where a high electrode/electrolyte interfacial area is needed. In this talk, particle/polymer electrospinning will be presented as a platform technique to fabricate a variety of electrode and membrane-electrode-assembly (MEA) products with unique and desirable compositions, architectures, and performance characteristics. Laboratory results will be presented for: (1) hydrogen/air fuel cell cathodes with Pt/C and PGM-free catalysts, (2) Pt/C hydrogen electrodes in a H2/Br2 redox flow battery, and (3) Si anodes for lithium-ion batteries.High particle content fibers containing Pt/C or Pt-alloy catalyst powder and a Nafion®perfluorosulfonic acid binder have shown great promise as electrodes in H2/air fuel cells. During electrospinning, Nafion ionomer migrates to the outer edges of the fiber, effectively creating a core-shell fiber morphology, with a low I/C ratio in the fiber interior. Additionally, the interior of the fiber contains nm-size pores and the outer surface of the Nafion shell exhibits enhanced hydrophobicity, due presumably to an accumulation of the polytetrafluoroethylene backbone chains (-CF2-CF2-) of Nafion. The resulting structure is advantageous in that the majority of catalyst particles are in a low I/C environment, nanopores in the fiber interior trap electro-generated water via capillary condensation, and the hydrophobic surface of the fibers facilitates electrogenerated water removal from the mat during fuel cell operation. The fuel cell power output using fiber mat anodes and cathodes is very high for a low Pt loading (0.10 -0.20 mg/cm2), near or above 1.0 W/cm2 for H2/air feeds in the range of 60-100% relative humidity.1,2 Additionally, the fiber mat cathodes exhibit excellent durability, with minimal power loss after accelerated voltage cycling tests. The hydrophobicity of fibers can be enhanced by adding polyvinylidene fluoride (PVDF) directly to the Nafion binder. Such blended binders in fiber/particle hybrid electrodes extend the operational lifetime of fuel cells with iron-based PGM-free cathode MEAs.As an extension of the fuel cell electrode work, electrospun Pt/C-Nafion nanofiber mat hydrogen electrodes have been made and tested for a H2-Br2 redox flow battery.3 The hydrophobic surface coating of core-shell fibers effectively blocks bromine species from poisoning the hydrogen electrode. In a 6.6 M HBr electrolyte lab-scale redox flow battery, the fiber mat electrodes worked extraordinarily well, with: (i) high power at low Pt loading, e.g., 650 mW/cm2 at 0.70 Vfor a loading of 0.11 mgPt/cm2 (6.4 kW/gPt) and 550 mW/cm2 at 0.65 V for a loading of 0.048 mgPt/cm2 (11.5 kW/gPt), (ii) no loss in power for more than 170 charge/discharge cycles, and (iii) a roundtrip current efficiency of 95%at both 0.2 and 0.3 A/cm2.For Li-ion battery applications, single and dual fiber anode mats have been prepared and evaluated, where the fibers contain a polymer binder (e.g., polyacrylic acid, polyamidimide, or polyvinylidene fluoride), Si nanoparticles as the electrochemically active material, and carbon powder as an electron conductor.4 Here, the gravimetric and areal capacities of the fiber anode are considerably higher than those of a conventional carbon particle anode. Inter-fiber voids allow for volume changes in Si during lithiation/delithiation, thus minimizing capacity fade during charge/discharge cycling (up to 600 cycles).AcknowledgmentsThis work was funded by the U.S. Department of Energy, Contract No. DE-EE0007653 from the Fuel Cell Technologies Office, through the Fuel Cell Performance and Durability Consortium (Fuel Cells Program Manager: Dimitrios Papageoropoulos) and Contract No. DE-EE0007215 from the Vehicle Technology Office.

Prediction of feasibility of Li and Fe doped natural olivine Mg2SiO4 for Li ion battery applications using Density Functional Theory

Li and Fe doped olivine Mg2SiO4 was studied using density functional theory. It was found that Li atom prefers to occupy M1 site to M2 site of Pbnm space group symmetry. Also, probability of Fe occupying M1 site over M2 site was also investigated and was observed, like Li, Fe also preferably occupies M1 site to M2 site. Two samples like Li2RLi2iMg6Si4O16 (R stands for replacement and i stands for interstitial site) and Li2RLi2iFe1Mg5Si4O16 were formulated by inserting Li at replacement site and interstitial site to maintain charge neutrality while Fe atom was inserted at replacement site. The probability of oxygen evolution during charging was minimized by incorporating redox active Fe+2 ion in Li doped Mg2SiO4. It was found that extraction of all the Li ions from Li2RLi2iMg6Si4O16 and Li2RLi2iFe1Mg5Si4O16 could be done at 3.68 V and 3.29 V with specific capacities of 198 mAh/g and 187 mAh/g respectively.