Lithium-ion Battery Cathode Research Articles

Uncertain lithium-ion cathode kinetic decomposition modeling via Bayesian chemical reaction neural networks

Lithium-ion batteries are the focus of significant recent research interest due to their use in energy storage systems, electric vehicles, and other green technologies. Under various abuse conditions, these batteries undergo thermal runaway, which can lead to rapid temperature rise, flammable gas release, and fires. Current simulation approaches for thermal runaway at the full-cell scale involve utilizing kinetic models fit to experimental data from individual battery components. Despite substantial experimental uncertainty in the literature for these component experiments, prevalent models have not accounted for such uncertainty or noise. Here, we introduce uncertainty quantification for lithium-ion battery cathode thermal decomposition modeling via a novel Bayesian inference methodology. This approach leverages Chemical Reaction Neural Networks and particle-based uncertainty quantification to infer uncertain kinetic parameters while eliminating traditionally used simplifications, allowing for improvements to model accuracy and broader consideration of correlated parameters. We validated this new framework by learning an uncertain decomposition model for NCM333 (nickel-cobalt-manganese) cathode materials using differential scanning calorimetry (DSC) measurements with added synthetic noise. Then, we quantified the uncertainty in NCM811 cathode thermal runaway chemistry using experimental DSC measurements from various sources in the literature. Our methodology’s ability to account for correlated Arrhenius parameters led to much broader uncertain parameter ranges and thus more generalizability at higher temperatures. We additionally found that the NCM811 model distribution learned directly from experimental data in the literature has 4σ onset temperature ranges up to 20 °C wide and specific reaction enthalpy ranges accounting for upwards of 80% of the mean value, carrying significant implications for downstream applications. Our work bridges the gap between noisy or uncertain experimental data and practical cell-scale simulations, thereby facilitating more realistic and robust thermal runaway models that support enhanced battery safety and performance optimization.

Study on the Characteristics of Spent Lithium-ion Battery Cathode Materials through Direct Recycling using Pretreatment Solvents

Study on the Characteristics of Spent Lithium-ion Battery Cathode Materials through Direct Recycling using Pretreatment Solvents

Influence of Mo/V coupled multi-electron reactions and the crystalline phase transition of VO2 on high specific capacity of lithium-ion batteries

To further improve the specific capacity and stability of amorphous vanadium-based lithium-ion battery cathode materials, MoS2 was introduced for the first time into the 70V2O5–30Li3PO4 (VP) glass cathode system. Both Mo and S participated in the redox reaction, achieving for the first time an increase in the V4+ content from 21.8% to 50.4%. This improved the electrical conductivity. Moreover, the realization of a Mo/V multi-electron coupling reaction promoted the capacity. The precipitation of LiV2O5 and MoP2O8 nanocrystals during electrocycling enhanced the cycling stability and reaction kinetics. Compared to VP, the capacity of 67V2O5–30Li3PO4–3MoS2 (VPMo3) was enhanced by more than 50% at a current density of 100 mA g-1, and the capacity retention after 50 cycles was improved by about 20%. Notably, the VO2 nanocrystals precipitated during the melt preparation underwent a metal-insulator phase transition (MIT), and their structural transformation affected conductivity.

Supercritical CO2-enhanced surface modification on LiFePO4 cathodes through ex-situ carbon coating for lithium-ion batteries

This work reports an efficient and effective ex-situ carbon-coating strategy for lithium iron phosphate (LFP) using supercritical CO2 (SCCO2) to improve its electrochemical performance. The SCCO2 possesses unique features including gas-like diffusivity and zero surface tension, which facilitate the penetration of carbon precursors among active materials and enable the formation of high-quality carbon-coated LFP (s-LFP/C). Compared to the conventional ball-milling process, the carbon coating layer assisted by SCCO2 comprises a higher fraction of graphitic carbon and fewer oxygen-derived functional groups, both are advantageous for electron transport. Additionally, the optimal s-LFP/C-containing half-cells reveal an outstanding specific discharge capacity (ca. 99 mAh g−1 at 10 C) and cycle life (ca. 95% for 150 cycles at 0.5 C) contributed from reduced charge-transfer impedance and comparable ionic diffusivity. Taken together, the SCCO2-coating technique highlighted herein offers a promising opportunity to build a homogeneous and highly conductive carbon layer for boosting the electrochemical characteristics of LFP cathode in lithium-ion batteries.

Thermodynamic equilibrium theory-guided design and synthesis of Mg-doped LiFe0.4Mn0.6PO4/C cathode for lithium-ion batteries

Mn-rich LiFe1−xMnxPO4 (x > 0.5), which combines the high operation voltage of LiMnPO4 with excellent rate performance of LiFePO4, is hindered by its sluggish kinetic properties. Herein, thermodynamic equilibrium analysis of Mn2+-Fe2+-Mg2+-C2O42−–H2O system is used to guide the design and preparation of in-situ Mg-doped (Fe0.4Mn0.6)1−xMgxC2O4 intermediate, which is then employed as an innovative precursor to synthesize high-performance Mg-doped LiFe0.4Mn0.6PO4. It indicates that the metal ions with a high precipitation efficiency and the stoichiometric precursors with uniform element distribution can be achieved under the optimized thermodynamic conditions. Meanwhile, accelerated Li+ diffusivity and reduced charge transfer resistance originating from Mg doping are verified by various kinetic characterizations. Benefiting from the contributions of inherited homogeneous element distribution, small particle size, uniform carbon layer coating, enhanced Li+ migration ability and structural stability induced by Mg doping, the Li(Fe0.4Mn0.6)0.97Mg0.03PO4/C exhibits splendid electrochemical performance.

Advances of LiCoO2 in Cathode of Aqueous Lithium-Ion Batteries.

Aqueous lithium-ion batteries offer promising advantages such as low cost, enhanced safety, high rate capability, and the ability to deliver considerable capacity at 1.8V, making them ideal candidates for large-scale reserve power sources for renewable energy. However, the practical application of aqueous lithium-ion batteries has been hindered by the poor cycle stability of layered cathode materials, including LiCoO2, in neutral aqueous electrolytes. This review examines the working principles, material limitations, and research progress of aqueous lithium-ion batteries. The types and characteristics of materials used in the cathode of aqueous lithium-ion batteries are summarized, with a primary focus on the attenuation mechanisms of LiCoO2 when used as the cathode material in aqueous electrolytes. Furthermore, this review explores the advancements in utilizing LiCoO2 in the cathode of aqueous lithium-ion batteries, as well as the combination with machine learning. By addressing these critical aspects, this review aims to provide a comprehensive understanding of aqueous lithium-ion batteries and shed light on future development and application prospects.

Redox-Active High-Performance Polyimides as Versatile Electrode Materials for Organic Lithium- and Sodium-Ion Batteries.

Organic electrode materials for rechargeable batteries show great promise for improving the storage capacity, reducing production costs, and minimizing environmental impact toward sustainability. In this study, we report a series of newly synthesized arylamine-based polyimides, TPPA-PIs, with three different bridge functionalizations on the imide rings and isomeric constituents that can work as versatile battery electrodes. As a lithium-ion battery cathode, a maximum energy density of 248 Wh kg-1 with high voltage operation up to 4.0 V can be achieved. As a lithium-ion battery anode, the TPPA-PIs showed a reversible storage capacity of 806 mA h g-1 at 100 mA g-1 current density with good rate capability up to a current density of 2000 mA g-1. Moreover, when applied as sodium-ion battery anodes, TPPA-PIs delivered an optimum specific capacity of up to 218 mA h g-1 after 50 cycles at a 50 mA g-1 current density and revealed a long cycling stability up to 1000 cycles under a high current density of 1000 mA g-1. More importantly, these electrochemical performances of TPPA-PIs are among the best compared with other reported polymer-based electrodes. The mechanistic studies show that both bridge functionalization on the imide units and isomerism impact the electrochemical performance by regulating their intrinsic properties such as charge storage behavior, ion diffusivity, and activation energy. We believe that such a detailed study of the structural design to electrochemical performance of these polymeric electrodes will offer insights into materials development and optimization for next-generation multifunctional energy storage devices in a wide range of applications.

Assessment of the visible light effect on one-step bacterial leaching of metals from spent lithium-ion batteries cathode pretreated by a bio-chemical lixiviant

Over the years, the extensive generation of spent lithium-ion battery cathodes (SLIBCs) and the absence of a practical recycling criterion for these hazardous yet metal-rich urban resources have posed a severe environmental threat. To address this issue, we propose an innovative hybrid strategy based on the characterization of SLIBCs, which includes pretreatment and an evaluation of the effect of visible light on one-step bacterial leaching of SLIBCs. This research presents, for the first time, an evaluation of the impact of visible light on the semiconducting properties of SLIBC and its potential to enhance extracellular electron transfer (EET) between the heterotrophic bacterium Bacillus foraminis and the waste. This increased electron transfer leads to more efficient metal bioleaching. In this strategy, we applied a novel bio-chemical pretreatment to modify the powder structure, considering the high metal content in the waste. This novel approach utilized metabolites from the spent medium of Bacillus foraminis cultures at pH∼5.4 and H2O2 (15% (v/v)). A pulp density of 10 g/L, a duration of 48 h, and a temperature of 60 °C resulted in the extraction of 98% of the manganese content. Subsequently, we assessed the bioleaching of pretreated SLIBC under both visible light and darkness conditions. Results indicate that, under 15,000 lux for 6 days, we achieved acceptable extraction rates: 68% Cu, 41% Li, 25% Co, and 16% Ni. In contrast, in darkness, extraction rates were notably lower, at 23% Cu, 9.9% Li, 3.9% Co, and 2.6% Ni. The increased extraction efficiency under visible light can be attributed to the proposed mechanism of light's effect on enhancing extracellular electron transfer between bacteria and SLIBC with semiconducting properties. FTIR, XRD, and FE-SEM analyses were also instrumental in understanding the effectiveness of the proposed strategy.

Features of the pyrolysis process of waste batteries using carbon black as an additive in the construction industry

The paper discusses the technology for recycling used lithium-ion batteries. At the same time, one of the important components in the technology for processing such waste is the recycling of anode material with the extraction of graphite or carbon black, which can be used in the production of fire bricks. It has been shown that materials and compounds contained in lithium-ion batteries are sources of hazardous waste of the second hazard class. At the same time spent accumulators are a source of valuable secondary material resources and contain in their composition up to 16 % wt. % of graphite.The paper proposes to consider the process of processing anode materials of lithium-ion batteries in order to obtain graphite and carbon black from them by pyrolysis. Experimental studies were carried out on the process of decomposition of cathode and anode materials of lithium-ion batteries separately, as well as their mixture by pyrolysis. When studying the kinetics and mechanism of pyrolysis of carbon-containing materials, thermogravimetric analysis of the following materials was carried out: 1) powdered graphite grade GAK-2 (GOST 10273-79); 2) graphite released from the anode during manual disassembly of the LKIT; 3) mechanically activated powders containing cathode material LiNiMnCoO2. The characteristics of the pyrolysis process were assessed using thermogravimetric and differential thermogravimetric analyses. Pyrolysis characteristics demonstrate that organic substances contained in batteries can decompose at a pyrolysis temperature of 500 °C for cathode materials and 450 °C for anode materials. This subsequently leads to higher efficiency in the extraction of valuable components with shorter grinding times. It has been shown that the decomposition of a mixture of lithium-ion battery materials removes a larger amount of organic components than the pyrolysis of anode and cathode materials separately. In this case, the rate of decomposition of the mixture of materials occurs more slowly. The activation energy values for lithium-ion battery materials after the pyrolysis stage were determined. The content of components in powder obtained after the pyrolysis stage was determined using the method of atomic emission spectrometry with inductively coupled plasma.

Revealing Aqueous-Processing Ni-Rich Cathode Cycling Performance in Term of Cathode Electrolyte Layer Formation and Phase Transition

Traditionally, Ni-rich cathodes for lithium ion batteries are produced by utilizing N-methyl-2-pyrrolidone (NMP) based casting. However, in order to prevent using the harmful solvent NMP, aqueous-processing method becomes one of the options.1 In this study, water-based electrodes have been produced to compare with the NMP-based electrodes. In addition to that, phosphoric acid addition was involved to modify the water-based electrode surface to improve the capacity retention.2 We used X-ray adsorption spectroscopy (XAS) to observe the existence of NiO phase in the aqueous processed electrodes due to Li/Ni disorder. The Galvanostatic cycling results shows that aqueous processed electrodes provide worse capacity retention compared with the NMP processed electrodes because of higher electron transfer resistance, which is caused by the cathode electrolyte layer (CEI) layer formation. Soft X-ray photoelectron spectroscopy (PES) results show that comparing to NMP-based electrodes, water-based electrodes contains more decomposition species from electrolyte in CEI layer after first battery cycle. From Operando X-ray diffraction, we observed the phase transition differences between these three types of electrodes. In this study we aim to answer if and/or how the additive phosphoric acid participates in the electrolyte degradation during battery cycling. A deeper understanding of the roles of acid can provide a new path to develop aqueous-processing electrodes method. Wu, F.; Kuenzel, M.; Diemant, T.; Mullaliu, A.; Fang, S.; Kim, J. K.; Kim, H. W.; Kim, G. T.; Passerini, S., Enabling High‐Stability of Aqueous‐Processed Nickel‐Rich Positive Electrodes in Lithium Metal Batteries. Small 2022, 2203874.Bichon, M.; Sotta, D.; De Vito, E.; Porcher, W.; Lestriez, B., Performance and ageing behavior of water-processed LiNi0.5Mn0.3Co0.2O2/Graphite lithium-ion cells. Journal of Power Sources 2021, 483.

(Invited) A Multifunctional Polynorbonene Binder System Enabling Next-Generation Lithium-Ion Batteries

Polynobornene (PNBE), a material commonly used in your shoes or for the tires of supercars, can also be highly influential to the development of next-generation batteries (Kim et al., 2022). When designing the batteries of tomorrow, we are interested in polymeric materials with precisely defined dynamic mechanical properties, increased ionic or conductivity, specific chemical interactions and moonshots like stable and healable interfaces (Lopez et al., 2019). PNBE provides high chemical and thermal stability, low shrinkage, and strong adhesion properties that lead to enhanced electrode stability and electrical conductivity(Le et al., 2020). Possessing a highly flexible nature allows PNBE to conform to the shape of an electrode – making PNBE an ideal multifunctional binder.Consider some persisting problems associated with batteries, for example Si electrodes typically fail due to cracks in the Si particles creating new surfaces for electrolyte decomposition/solid electrolyte interphase formation, and due to the Si becoming electrically disconnected from the rest of the electrode and ultimately terminating cycling (Ryu et al., 2004) . PNBE can address both aforementioned pain points, low shrinkage and flexibility can help mitigate the impact of cracking that occurs within an electrode over time by maintaining the structural integrity, and strong adhesion properties promote effective binding of the active material and the rest of the electrode. With increasing concerns about cobalt, there has been a move to replace oxides with phosphates. Substituting a substantial fraction of Mn, for Fe in LiFePO4 leads to a material with an energy density approaching that of the oxides, while substantially lessening environmental concerns. Unfortunately, Mn dissolution causes a poor cycle lifetime.In an effort to reduce Mn dissolution, a mixture of PNBE and PVDF was used as a binder system. The PNBE was designed to have ether-type comb-branch functionalities that aid in Mn trapping, while the PVDF had suitable viscosity and mechanical properties. Figure 1 shows cycle lifetime results conducted at 45°C on a 2Ah LMFP-Graphite cell containing a 4%PVDF/1%PNBE binder system. The results show very good lifetime, with the capacity retention nearly 90% after 1,000 cycles. Given the difficulty with cycling of LMFP due to Mn dissolution, these results show good promise for this approach.This talk will highlight the opportunities and challenges of custom and enabling PNBE binder systems for LMFP, and other battery systems. References Kim, N.-Y., Moon, J., Ryou, M.-H., Kim, S.-H., Kim, J.-H., Kim, J.-M., Bang, J., & Lee, S.-Y. (2022). Amphiphilic Bottlebrush Polymeric Binders for High-Mass-Loading Cathodes in Lithium-Ion Batteries. Advanced Energy Materials, 12(1), 2102109. https://doi.org/https://doi.org/10.1002/aenm.202102109Le, D., Samart, C., Lee, J.-T., Nomura, K., Kongparakul, S., & Kiatkamjornwong, S. (2020). Norbornene-Functionalized Plant Oils for Biobased Thermoset Films and Binders of Silicon-Graphite Composite Electrodes. ACS Omega, 5(46), 29678–29687. https://doi.org/10.1021/acsomega.0c02645Lopez, J., Mackanic, D. G., Cui, Y., & Bao, Z. (2019). Designing polymers for advanced battery chemistries. Nature Reviews Materials, 4(5), 312–330. https://doi.org/10.1038/s41578-019-0103-6Ryu, J. H., Kim, J. W., Sung, Y.-E., & Oh, S. M. (2004). Failure Modes of Silicon Powder Negative Electrode in Lithium Secondary Batteries. Electrochemical and Solid-State Letters, 7(10), A306. https://doi.org/10.1149/1.1792242 Figure 1

Development of Novel High Capacity Fluoride Ion Battery Cathode Utilizing Anion Redox of Sulfur

All-solid-state fluoride-ion batteries (FIBs), which are based on the shuttling of fluoride ions, have been considered as one of the promising alternates for next-generation energy storage devices because of high theoretical energy density and safety. Benefiting from the multi-covalent fluorination process, metal/metal fluorides (M/MFx) have been firstly utilized as electrode materials for FIBs with high theoretical energy densities.[1] However, M/MFx systems suffer from exceptionable volume expansion upon fluorination process due to the close-packed metal atoms, which would cause blockage of the F- diffusion pathway, resulting in devastating damage to the electrode-electrolyte interfaces. To solve these problems, cathode materials that utilize topotactic fluoride ion intercalation reactions, similar to the electrode materials applied in lithium-ion secondary batteries, are being developed.[2] Cathode materials that utilize topotactic intercalation of fluoride ions are often composed of heavier elements than the cathodes of lithium-ion batteries that use the same type of reaction mechanism, and effective anion redox is required if capacity is to be increased beyond that of lithium-ion secondary batteries.In this research, we investigated Sr2F2Fe2OS2 (SFFOS) compound with a layered structure as a novel cathode material for all-solid-state FIBs, and evaluated its electrochemical properties and elucidated the charge compensation mechanism using anion redox of sulfur.SFFOS was synthesized by a solid-state reaction under vacuum environment using SrF2, SrO, Fe, and S.[3] SFFOS/La0.9Ba0.1F2.9/vapor grown carbon fiber (VGCF) was used as the composite cathode, La0.9Ba0.1F2.9 as the electrolyte and Pb/PbF2/ La0.9Ba0.1F2.9/VGCF as the composite anode to construct the electrochemical cell. Charge-discharge measurements were carried out in the cut-off voltage range of -1.5 to 1.5 V at 140°C. Ex-situ X-ray Diffraction (XRD), X-ray absorption spectroscopy (XAS) measurements of Fe K-edge, S K-edge, O K-edge and F K-edge were carried out under different state of charge during the 1st and the 2nd cycle.SFFOS showed reversible intercalation/de-intercalation of fluoride ions and a capacity of ~6.1 fluoride ions per unit cell (403 mAh g-1). The charge compensation mechanism was revealed for SFFOS by XAS measurements, where S redox contributed to the whole voltage range from -1.5 V to 1.5 V vs. Pb/PbF2, and Fe+2/+3 redox contributed from the middle SOC. The S-S dimers were formed upon charging, which was similar to the trapped O2 molecules observed in lithium-excess metal oxide during charge process[4]. Not only can the F- anions insert around Fe to form Fe-F bonds, but the excess F- anions can also occupy the Sr-S interstitial layers in the original lattice. Compared to the Fe-based layered oxide Sr3Fe2O5, the Fe-based oxysulfide SFFOS showed a lower average voltage but a higher specific capacity. We believe that this study could provide a new understanding of sulfur-based charge compensation and electrochemical fluorination reactions. Reference s : [1] D. Zhang, K. Yamamoto, Y. Uchimoto et al., J. Mater. Chem. A, 2021, 9, 406–412.[2] Y. Wang, K. Yamamoto, Y. Uchimoto, et al., Chem. Mater., 2022, 34, 609–616.[3] Kabbour H, Janod E, Corraze B, et al ., J. Am. Chem. Soc., 2008, 130(26): 8261-8270.[4] R. A. House, P. G. Bruce, et al., Nat. Energy 2020, 5, 777–785. Figure 1

Ex-Situ Studies of Hydraulic Pressure Effect on the Electrochemical, Structural and Morphological Properties of Nickel-Rich NMC

The development of industry and technology, as well as the Earth's growing population, is forcing an ever-increasing demand for energy and raw materials. In tandem with this demand, efficient energy storage is also necessary and equally important. One of the most attractive forms of energy storage, has proven to be electrochemical cells, which allow the conversion of chemical reaction energy into electricity. The most promising cell type turned out to be lithium-ion batteries, and this was due to the attractive properties of lithium, which have the high negative standard potential (about -3 V) and high specific capacity (3860 Ah kg-1) 1. The majority of commercial lithium-ion batteries (LIB) are manufactured using roll-to-roll (R2R) wet processing technology (i.e., the slurry method), where active battery powder, conductive carbon powder and inactive binding agent are mixed in a organic solvent , cast onto metallic current collectors and then dried 2. Up next, the electrode layers undergo a calendaring process in which they are compressed. It is important to clarify the effect of hydraulic pressure on the properties of electrode materials and correlate this relationship to its type and characteristics. An inadequate selection of hydraulic pressure conditions can adversely affect the properties of the active battery material, leading to grain cracking and thus the capacity drop. The phenomenon of cracking of nickel-rich NMC secondary particles is considered to be the one of the critical causes that deteriorate the long-term cyclic stability of the NMC cathode in lithium-ion batteries 2,3.In this study various methods are applied to observe and understand the electrode properties that accompany grain fracture and electrode preparation conditions. Morphological changes that occur before and after the electrode calendaring and further the cell’s operation can be examined by scanning electron microscopy (SEM). This technique can be used as a tool to gather information about the composition of cathode materials while tracking a realistically operating battery 3. Another analysis technique is the ex-situ Raman spectroscopy, which allows us to gather detailed information on the local properties of the electrode material. It provides details on phase transitions and the causes of capacity loss over successive battery cycles 4. The information about grain size, crystallographic parameters and the phases present in the sample, can be gathered by X-ray diffraction (XRD). In this research all these methods will be employed to identify possible defects present in electrode materials before and after cycling with regard to applied hydraulic pressure during electrode preparation. We will determine the most suitable hydraulic pressure conditions and correlate our results with initial material morphology and crystallographic structure as well as the electrochemical response. A detailed data analysis will be reported at the conference. Funding for this work was provided by the National Science Center in Poland under the Sonata BIS 11 program (No. UMO-2021/42/E/ST5/00390). A. Czerwiński. Akumulatory, baterie, ogniwa. (2005). Kirsch, D. J. et al. Scalable Dry Processing of Binder-Free Lithium-Ion Battery Electrodes Enabled by Holey Graphene. ACS Appl Energy Mater 2, 2990–2997 (2019). Cheng, X. et al. Real-Time Observation of Chemomechanical Breakdown in a Layered Nickel-Rich Oxide Cathode Realized by in Situ Scanning Electron Microscopy. ACS Energy Lett 6, 1703–1710 (2021). Flores, E., Novák, P. & Berg, E. J. In situ and Operando Raman spectroscopy of layered transition metal oxides for Li-ion battery cathodes. Front Energy Res 6, (2018).

Doping Strategy to Improve the Electrochemical Behavior of Lithium Rich Transition Metal Oxides As Cathodes for Lithium-Ion Batteries

Lithium-rich transition metal oxides are considered a promising cathodic solutions in Li-ion batteries to meet the growing energetic demand, thanks to their high specific capacity and operational voltage [1-2]. Li-rich layered materials have a general stoichiometry Li1+xTM1-xO2, in which TM is a blend of transition metals, as Ni, Mn, Co [2]. They stand out due to their high lithium concentration and specific capacity [1-2]. The higher capacity of Lithium-Rich can be attributed to the specific anionic redox reaction in the bulk at above 4.5 V. Nevertheless, large irreversible capacity loss in the first cycle, poor rate capability, mean working potential decay upon cycling and cobalt content are still major drawbacks that are hindering commercialization. In order to make these materials up scalable to industrial production, it is important to consider the reduction of costs and the toxicity of raw materials, in particular cobalt. Cobalt reduction has been identified as major driver to improve the environmental benignity of batteries and the sustainability of the overall production-consumption-recycling lifecycle. Several efforts to reduce these problems have been made, including the development of different synthetic strategies, doping and surface modification. The most, widely explored, chemical strategy to mitigate the voltage decay and structural degradation in Lithium Rich cathodes is the doping. Elemental doping can be divided into cation and anion doping. As an example, incorporation of redox inactive metals, such as Al, Zr, Ti, has been proposed in order to stabilize the lattice as well as the partial replacement of lithium ions with other alkali cations, e.g. K and Na; or doping the oxygen anion sublattice. In this communication, we present our doping approaches. In particular, the simultaneous replacement of cobalt in the layered structure with aluminum and lithium (over-lithiation). Moreover, we present over-lithiated Co-free materials where the introduction of different amount of iron has been investigated. The characterization of these novel layered materials is reported in terms of composition, structure, morphology and electrochemical performances. These approaches can be applied as a strategy to mitigate the voltage decay and reduce the Cobalt content.[1] Ji, X. et al. Journal of Power Sources 487, (2021).[2] Zhao, S. et al. Angewandte Chemie - International Edition 60, 2208–2220 (2021).

(Invited) Grain Texture and Transport in Sintered Lithium Cobaltite

Reversible exchange of lithium from lithium cobaltite (LCO) with the layered rock-salt structure was first reported by Goodenough in 1980 [1]. It has since become a critical component in the cathode of lithium-ion batteries that power portable electronics like cell phones, laptop computers, and cordless power tools. The rate of lithium diffusivity in LCO particles ranges from 10-7 to 10-11 cm²/s depending upon the state of charge and the method of measurement [2]. Lithium diffusivity in LCO because of its layered structure is also dependent upon crystallographic direction. In thin-film, micro-batteries (TFMB’s), the crystallographic orientation of LCO is controlled through choice of conditions for deposition and crystallization [3]. The diffusivity of lithium is significantly greater within rather than across the basal plane [4]. Orientations of (104) and (110) are preferred for rate performance.Continuous, roll-to-roll sintering of LCO ribbon with thicknesses down to 10 µm was recently demonstrated [5]. The LCO ribbon because it is sintered and self-supporting can in principle serve as a mechanical support to reduce the proportions of inactive battery components to dramatically increase energy density. A possible way of creating a solid-state battery with LCO ribbon is to capitalize on the LiPON solid electrolyte from TFMB’s. Both composite and dense cathodes can be envisioned. Energy densities greater than 1500 Wh/L are possible. The practicality and design of a cathode-supported battery depends upon lithium diffusion in the LCO and charge transfer resistance at the interface with the separator. Ideally, transport is sufficiently facile that acceptable rate performance in a battery is realized with cathode thickness of greater than 20 µm.In this work, we report on characterization of lithium diffusivity and ohmic losses in sintered LCO with controlled grain textures. LCO cathodes with thicknesses of 15-30 µm with random and (003) grain textures were prepared by tape casting and rapid sintering. The (hk0) texture was made by taking advantage of the (003) textured green tape; approximately 200 layers were stacked and cold-welded to form a block with a thickness of ~8 mm. The sintered block was diced to expose the edge with the favorable (hk0) orientation. Electron backscatter diffraction maps and pole figures that illustrate the grain structure and texture are shown in Fig. 1. The texture is so strong that material is orthotropic in character.Lithium diffusivity and ohmic cell resistances were determined as a function of state of charge by galvanostatic intermittent titration [7]. An average diffusivity to use as a single figure of merit was also determined by fitting of capacities measured as a function of rate of discharge from a cut-off potential of 4.3 V. Rates of lithium diffusion in sintered LCO cathodes with the (hk0) texture is 0.09 µm²/s and approximately twelve-fold greater than for the (003) texture, 0.0076 µm²/s. Ohmic loss was also found to depend upon grain texture. It was approximately 60-100 Ωcm² for (hk0) texture and >500 Ωcm² for (003). A reasonable explanation for the elevated resistance is that charge transfer occurs more easily with the (hk0) texture.[1] K. Mizushima, P.C. Jones, P.J. Wiseman, and J.B. Goodenough, Mat. Res. Bull., 15 (1980) 783-789, https://doi.org/10.1016/0025-5408(80)90012-4.[2] K. Dokko, M. Mohamedi, Y. Fujita, T. Itoh, M. Nishizawa, M. Umeda, and I. Uchida, J. Electrochem. Soc., 148 (2001) A422-A426, https://doi.org/10.1149/1.1359197.[3] J. Trask, A. Anapolsky, B. Cardozo, E. Januar, K. Kumar, M. Miller, R. Brown, and R. Bhardwaj, J. Power Sources, 350 (2017) 56-64, https://dx.doi.org/10.1016/j.jpowsour.2017.03.017.[4] J. Xie, N. Imanishi, T. Matsumura, A. Hirano, Y. Takeda, and O. Yamamoto, Solid State Ionics, 179 2008) 362-370, https://doi.org/10.1016/j.ssi.2008.02.051.[5] C. Tanner and J. Lorenzo, ECS Meet. Abstr. MA2022-02 (2022) 2482, https://doi.org/10.1149/MA2022-0272482mtgabs.[6]J.B. Bates, N.J. Dudney, G.R. Gruzalski, R.A. Zuhr, A. Choudhury, C.F. Luck, and J.D. Robertson, Solid State Ionics, 53-56 (1992) 647-654, https://doi.org/10.1016/0167-2738(92)90442-R.[7] C.J. Wen, B.A. Boukamp, R.A. Huggins, and W. Weppner, J. Electrochem. Soc., 126 (1979) 2258-2266, https://doi.org/10.1149/1.2128939. Figure 1

Influence of Process Conditions during Aqueous and Direct Recycling of NMC811 Cathodes

A binder-solvent system consisting of polyvinylidene fluoride (PVDF) and N-methyl-2-pyrrolidone (NMP) is commonly used in state-of-the-art cathodes for lithium-ion batteries [1]. However, NMP is highly toxic and requires energy-intensive production processes as well as solvent recovery and purification systems to prevent uncontrolled evaporation [2]. To reduce the cost and environmental impact of cathode production, carboxymethyl cellulose (CMC) and water can be used as an alternative to PVDF and NMP [3]. In addition, the use of water instead of organic solvents for binder deactivation in aqueous processed cathodes would make direct recycling much more attractive.This study investigates the process conditions for direct recycling of aqueous processed NMC811 cathodes by varying parameters such as the amount of water, process time, and pH of the water bath. The recycled NMC materials are characterized by various techniques, including thermogravimetric and mass spectrometry (TG-MS), X-ray photoelectron spectroscopy (XPS), and electrochemical measurements such as EIS and galvanostatic cycling.The results show that the ratio of water to NMC has a significant effect on the amount and type of surface species formed on the NMC811 surface. The ratio of NMC811 to water was varied between 1:1 and 1:50, representing possible water concentrations in the direct recycling process. The formation of surface species directly affects the electrochemical performance. Higher water concentrations were associated with higher charge transfer resistances and lower discharge capacities. TG-MS and XPS measurements identified the additional species as the cause. These were mainly transition metal carbonates and hydroxides.In addition, by adding aluminum foil to the water-NMC mixture, the process conditions during the current collector detachment step within direct recycling are investigated. In the aqueous medium, the high pH of about 11.5 leads to the formation of aluminum-containing species due to aluminum corrosion. These species form a surface layer on the NMC particles, which limits the amount of Li leached, but also induces higher polarization. When aluminum corrosion is prevented by adding acid to regulate the pH, the material leaches more Li but also has less polarization. Overall, the importance of controlling the process conditions during aqueous and direct recycling is demonstrated.

Tin Nanoparticles As High-Performance Anode for Sodium-Based Batteries: Preparation and Operando XRD Investigation

Lithium-ion batteries (LIBs) have been dominating the energy storage market for decades, but the political and economic issues related to raw materials availability and cost is fueling the search for new electrochemical solutions. Sodium-based batteries (SBBs) are the most promising substitute to LIBs, because the similar physico-chemical properties of these two alkali guarantees the knowledge transfer from LIBs to SBBs and facilitate the working phenomena comprehension (so called rocking-chair mechanism).The materials used as cathodes in LIBs often have a sodium-based analogue that offers acceptable performances in SBBs, yet this is not the case for anode materials. Graphite is the most used material as anode in LIBs and its electrochemical behaviour with lithium is based on the intercalation mechanism. Unfortunately, Na does not intercalate into graphite, pushing scientists to find other solutions, such as hard/soft carbons and alloying elements [1]. Tin, in particular, has a high theoretical capacity (847 mAh/g) due to the formation of the high-sodium-content alloy Na15Sn4, making it a promising candidate for the next generation of SBBs [2].In our work tin nanoparticles and tin/carbon composites are prepared and analysed through electrochemical techniques. Being the sodiation of tin an alloying reaction, during the half cells discharge the increasing of sodium amount in tin is observed as the formation of high-sodium-content alloys according to the related phase diagram. We investigated the evolution of the system by operando XRD carried out at low current rate (coulometric titration), to confirm the expected phases based on the phase diagram are indeed observed. The results are corroborated by the electrochemical tests (galvanostatic cycling and voltammetry). Experimental data and theoretical information from literature are used to identify crystalline and amorphous phases [3]. The main issue linked to alloying materials is the high-volume expansion after discharge (420 % for tin), leading to fast capacity fade because of the solid electrolyte interphase (SEI) continuous destruction. For this reason, we prepared Sn/carbon composite structures able to mitigate the expansion and avoid the tin aggregation. In this way the capacity retention is improved, making this material a valid alternative for next generation batteries.

The Influence of Ammonia Concentration on the Precipitation of Ni(OH)2 Precursor in the Synthesis of LiNiO2 Cathode Materials for Lithium-Ion Batteries

Lithium-ion batteries have been implemented in the energy storage market for many decades, used as rechargeable batteries in portable devices, electric vehicles and a wide range of other applications. Ni-rich layered oxides as cathode materials in Li-ion batteries are of great interest due to their higher energy density and theoretical capacity of 274 mAh/g. [1] To improve fast lithium-ion diffusion in lithium-ion battery cathodes, enhance the limited capacity due to oxygen release and phase changes, reduce cost and toxicity and most importantly, inhibit unethical mining of cobalt. Alternative compounds to replace LiCoO2 are investigated by substituting different transition metals, such as Ni, Mn, or Al on the Co site in the structure. The increase of the Ni content and decrease of the Co content increases the capacity and lowers the costs in $/kWh, as Ni provides higher performance and a high energy-density. To cope with the higher demand of volume constrained applications [2], the volumetric energy-density is to be considered and is achieved by a high tap density of the active material, which is related to particle size, particle size distribution and morphology. [3] However, for high-nickel content cathodes, degradation processes like Li/Ni mixing [4], surface layer deconstruction [5], particle cracking[6], decomposition reactions with the electrolyte [7] and slow Li+ diffusion kinetics [8] occur, leading to lower capacity retention, a loss of capacity in the first cycle and thus an overall insufficient cycling stability.There are many research publications about optimising the calcination process of the Ni(OH)2 precursor and LiOH*H2O, [9][10][11], but currently, very little focus on the precursor material itself, it’s particle size and morphology, which affects the structural and electrochemical behaviour. The accumulation of mechanical strain due to repeated c-axis contraction and relaxation during charge/discharge processes lead to particle cracking, electrolyte infiltration, structural decay and results in a reduced electrochemical performance. To counter this, a large study regarding the morphology, particle size, and electrochemical behaviour of Ni(OH)2 precursor material produced in a highly controlled environment (batch stirred tank reactor BSTR) has been undertaken and the first results are presented here. A higher transition metal to ammonia ratio during synthesis leads to larger and more spherical secondary particles, a narrow particle size distribution, a higher tap density and also improved electrochemical cycling.[1] T. Ohzuku, A. Ueda and M. Nagayama, J. Electrochem. Soc., 1993, 140, 1862.[2] A. El Kharbachi, O. Zavorotynska, M. Latroche, F. Cuevas, V. Yartys and M. Fichtner, J. Alloys Compd., 2020, 817, 153261.[3] S. Yang, X. Wang, X. Yang, Z. Liu, Q. Wei, and H. Shu, Int. J. Electrochem., 2012, 9.[4] R. V. Chebiam, F. Prado and A. Manthiram, J. Electrochem. Soc., 2001, 148, A46-A53.[5] A. Gosh, J. M. Foster, G. Offer and M. Marinescu, J. Electrochem. Soc., 2021, 168, 020509.[6] R. Ruess, S. Schweidker, H. Hemmelmann, G. Conforto, A. Bielefeld, D. A. Weber, M. T. Elm and J. Janek, J. Electrochem. Soc., 2020, 167, 100532.[7] H. Rong, M. Xu, L. Xing and W. Li, J. Power Sources, 2014, 261, 148-155.[8] M. D. Radin, S. Hy, M. Sina, C. Fang, H. Liu, J. Vinckeviciute, N. Zhang, M. S. Wittingham, Y. S. Meng and A. Van der Ven, Adv. Energy Mater., 2017, 7, 1602888.[9] M. Bianchini, F. Fauth, P. Hartmann, T. Brezesinski and J. Janek, J. Mater. Chem. A, 2020, 8, 1808.[10] J. Välikangas, P. Laine, M. Hietaniemi, T. Hu, P. Tynjäla and U. Lassi, Appl. Sci., 2020, 10, 8988.[11] C. S. Yoon, M. H. Choi, B-B. Lim, E-J. Lee and Y-K. Sun, J. Electrochem. Soc., 2015, 162, A2483.

(Invited) Circular Manufacturing of Next-Generation Lithium-ion Battery Cathode Materials with R2R Molten Salt Electrodeposition

For the past few years, Xerion has been developing a roll-to-roll (R2R) molten salt electrodeposition technology (DirectPlateTM) for circular manufacturing of lithium-ion battery cathodes. Cathode materials such as LiCoO2, Li(NixMyCoz)O2, and LixMnyOz are demonstrated with good electrochemical properties. DirectPlateTM cathodes are distinctly different from conventional slurry-cast electrodes combining several notable properties: they are very dense with less than 10% porosity, free of additives (carbon and polymer binder), and their crystal orientation can be accurately controlled, enabling high-rate operation at or beyond state-of-the-art areal capacity loading (3-4 mAh/cm2). As Li+ diffusion primarily occurs through the single crystalline domains aligned vertically to the current collector, DirectPlateTM LiCoO2 cathodes delivers good electrochemical properties in a solid-state cell without the need to infiltrate electrolyte into the cathode. We further demonstrate that end-of-life DirectPlateTM cathodes can be efficiently re-lithiated and repaired with a short molten salt treatment; or they can be upcycled into another cathode material with a completely different composition. Finally, we demonstrate that the DirectPlateTM cathode can be employed as a redox membrane for direct lithium extraction from various lithium-containing solutions. Integrating the collective mineral refinement, electrode fabrication and recycling capabilities into the R2R DirectPlateTM platform enables next-generation circular battery manufacturing with much lower energy and environmental cost.

Mixed-Dimensional (1D-2D) Carbon as a Conductive Additive and Enabler for Next Generation Lithium-Ion Batteries

The race to develop the next generation of lithium-ion batteries with higher performance metrics (e.g. energy density, power density, cyclability) has spurred interest in carbon allotropes, such as carbon nanotubes (1D) and graphene (2D). Herein, a new multi-dimensional carbon material, comprised of long and entangled 1D nanotubes that unfurl into a spanning network of 2D sheetlets, is investigated as a conductive additive in lithium-ion battery cathodes. Compared to conventional conductive additives, this so-called 1.5D carbon material improves both electrical and thermal pathways between battery active materials within the electrode.In this presentation, the electrical, thermal, and electrochemical properties of the mixed-dimensional (1.5D) carbon are compared to conventional additives such as carbon black and graphite. Higher active material loadings, less heat generation, and more energy-dense cells can be enabled by the improved electrical conductivity, where three times less carbon black results in one order of magnitude higher electrode conductivity. The thermal conductivity of these cathodes is also enhanced in both the through- and in-plane directions, which is beneficial for battery thermal management. For instance, using a third of the carbon amount results in more than 30% and 240% higher through- and in-plane thermal conductivity values, respectively. The combination of these properties translates to overall improvements in electrochemical performance metrics including rate capability, lower cell impedance, and higher achievable capacities. Compared to cells with conventional carbon black, there is a 20% reduction in ohmic resistance determined by electrochemical impedance spectroscopy. In terms of capacity retention and rate capability, full cells cycled at a 2C charge and 0.5C discharge rate demonstrated 2.5% higher initial capacity than carbon black with a retention of 95% vs 94.4% after 120 cycles.