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At least 19 records

Layer spacing gradient (NaLi) 1–x CoO 2 for electrochemical Li extraction

Designing materials with high Li to Na selectivity is the key for direct extraction of Li from unconventional sources, such as seawater, without complex separations. However, material discovery is hindered by an insufficient understanding on how a material's composition and structure relate to Li selectivity during electrochemical co-intercalation. Here, we synthesized a core-shell structured (NaLi) 1-x CoO 2 with a core Li phase (Li 0.94 CoO 2 ), a shell Na phase (Na 0.51 CoO 2 ), and a transition intermediate phase via Na ion-exchange of parent Li 1-x CoO 2 . We reveal that the chemical compositions and spatial relation of these phases play critical roles in governing high Li to Na selectivity. The core Li phase restricts large layer spacing expansion and inhibits Na intercalation. The shell Na phase serves to maintain the electrode stability against further Na ion exchange. With the layer spacing gradient design, we achieved a high Li selectivity of 1.5 x 10 5 with a recovery of similar to 7.6:1 Li to Na from 1:20,000 initial ratio.

36 MATERIALS SCIENCE↗

Asymmetric pathways for lithium extraction and recovery based on the two-phase equilibrium of layered oxides

Electrochemical intercalation offers a promising platform for Li + extraction. However, only limited types of electrode materials have been investigated. The challenge to broaden and tailor materials for electrochemical intercalation-based Li + extraction lies in the lack of understanding of material’s response upon co-intercalation of multiple ions, therefore, paired process design to enable reversible Li + extraction and recovery. Here, we showcase the design of asymmetric ion pathways for Li + extraction and recovery for host material with complex Li + and Na + interaction using layered cobalt oxide as a model material. The two-phase equilibrium of Na 0.48 CoO 2 and Li 0.94 CoO 2 governs Li + selectivity when a high depth of intercalation is achieved (low vacancy level). We show that the relative rate between ion exchange and intercalation is critical to determine the ion pathways. The relationship can be quantitatively compared using the average pseudo ion exchange rate (C pseudoIX ) and the intercalation rate (C inter ). The ion pathways at the three regimes with C pseudoIX > C inter , C pseudoIX ~ C inter , and C pseudoIX < C inter are constructed. By selecting the optimized ion pathway and particle size, we demonstrate 9.7×10 4 Li + selectivity with 99% purity Li + recovery from an initial 1:1000 Li: Na molar ratio solution using 115 mAh/g specific capacity.

electrochemistry↗

Selective leaching and solvent extraction of Lithium from spent batteries

Pre-extracting Li from spent lithium-ion batteries (LIBs) is crucial because the recovery efficiency of Li is low after other critical metals have been extracted. Traditional methods involving black mass roasting followed by water leaching have resulted in the extraction of 76 % Li and 61 % Al. However, pre-leaching Li from pretreated black mass using an oxalic acid solution at both ambient and elevated temperatures significantly improved results, achieving 98.1 % Li, 99.5 % Al, and 100 % Fe extraction while leaving Ni, Co, Mn, and Cu behind under optimal conditions. Oxalic acid crystals were recovered by refrigerating the leach solution at temperatures below 5 °C and were reused with nearly identical leaching efficiency. Selective extraction of Li from the oxalate leach solution was achieved using Cyanex® 936P under optimal conditions. Here, due to its extremely low Li extraction efficiency, Dichloromethane proved unsuitable as a diluent. Comparative extraction tests using Cyanex® 936P, Cyanex® 272, and DEHPA in kerosene demonstrated that Cyanex® 936P is an excellent extractant for Li, effectively separating it from other impurities. Under optimal conditions, 98.8 % of available Li was extracted using 20 % Cyanex® 936P, compared to 51.1 % with Cyanex® 272 and 39.9 % with DEHPA in kerosene. Additionally, stripping Li from Cyanex® 936P using H 2 SO 4 and HCl was explored, with HCl yielding the best performance.

Black mass↗

Identifying critical features of iron phosphate particle for lithium preference

One-dimensional (1D) olivine iron phosphate (FePO 4 ) is widely proposed for electrochemical lithium (Li) extraction from dilute water sources, however, significant variations in Li selectivity were observed for particles with different physical attributes. Understanding how particle features influence Li and sodium (Na) co-intercalation is crucial for system design and enhancing Li selectivity. Here, we investigate a series of FePO 4 particles with various features and revealed the importance of harnessing kinetic and chemo-mechanical barrier difference between lithiation and sodiation to promote selectivity. The thermodynamic preference of FePO 4 provides baseline of selectivity while the particle features are critical to induce different kinetic pathways and barriers, resulting in different Li to Na selectivity from 6.2 × 10 2 to 2.3 × 10 4 . Importantly, we categorize the FePO 4 particles into two groups based on their distinctly paired phase evolutions upon lithiation and sodiation, and generate quantitative correlation maps among Li preference, morphological features, and electrochemical properties. By selecting FePO 4 particles with specific features, we demonstrate fast (636 mA/g) Li extraction from a high Li source (1: 100 Li to Na) with (96.6 ± 0.2)% purity, and high selectivity (2.3 × 10 4 ) from a low Li source (1: 1000 Li to Na) with (95.8 ± 0.3)% purity in a single step.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Microchannel-based Membrane-less Extraction of Li from Unconventional Lithium Sources & the Separation of REE

This final report provides an overview of the Project's entire duration, covering July 1, 2021 to December 31, 2023. It primarily focuses on the achievements, technological developments, and unique challenges the team faced while working on separating and extracting Lithium from produced waters. The project's primary aim was to create an integrated, high-throughput, membrane-less, and modular microfluidic platform that could extract Lithium from unconventional sources. We have successfully met all goals and milestones envisioned in the SOPO document. The most critical primary milestones, including the Go-No-Go milestone (refer to the Gantt chart in the Appendices), were successfully accomplished. We demonstrated phase separation (>90%) and extraction (>85%) performance in the MPSE using synthetic, and representative produced water composition feed at 50 ml/min total flow through MPSE 36. We have also performed a parametric study of the MPSE operations, beyond the scope of SOPO, exploring operating conditions of current and broader interest. The extended investigation of operational parameters is concurrent with our efforts to seek further development of the MPSE technology beyond the scope of the Project. Along these lines of development, we have made efforts to be responsive to DOE calls for technological developments of other types of resources (beyond PW) for the recovery of Critical Materials and higher TRL development (beyond TRL 4). During the work on this Project, we developed and implemented three innovative technical approaches that emerged from our efforts to successfully meet the Project milestones. The innovative & original technical approaches developed and implemented in this Project are now the contributions to process engineering that could be clearly credited to the Project. First, Convergent Design Approach is a comprehensive feedforward & feedback loop of four design phases: i) design for functionality, ii) design for manufacturing, iii) design for sustainability, and iv) design for market. Next was Process Intensification. A major aim of this Project was to create an innovative phase separation & extraction microscale-based technology for Li separation – thus the words microchannel-based in the Project title. A microscale-based technology is intrinsically in the center of the Process Intensification domain as defined by its unique principles. Therefore, Process Intensification was implicitly envisioned in the Project’s SOPO. Lastly, Time Scale Analysis is a novel tool for discovering the needs and directions of Process Intensification implementations in any process technology. This Project is fully credited for developing and implementing the three novel technical approaches mentioned above. These are general contributions to process engineering that emerged from this Project. Beyond the original SOPO scope, the OSU-U.Pitt research group utilized a Convergent Design methodology, integrating first-principles mathematical modeling with experimental validation on the Minimum Development Vehicle. By creating these Digital Twins, the team rapidly assessed manufacturing iterations to support TEA analysis. This framework further enabled the development of advanced Surface Modification Techniques, where hydrophobic and oleophobic coating strategies were optimized via Digital Twin tools and validated through rigorous 100-hour longevity testing. TEA Analysis: The closing efforts of this Project were focused on the TEA analysis. TEA analysis had two primary functions: i) enabling critical assessments of design variations withing 10 the Concurrent Design Approach, thus enabling evolution of the MPSE design to reach faster- better-cheaper alternatives; and ii) to create a bridge between the accomplishments of this Project and future projects of higher TRL, beyond TRL 6 level. It is important to note that the TEA model created in the Project stirred the technological solutions for the recovery of critical materials toward a vision of a very profitable modular plant that has unique zero-waste water discharge signature. More importantly, thanks to our experimental performance data and conservative assumptions, the TEA model predicts minimal technological and investment risks. Low cost of a modular unit of a nominal capacity of [1000 tons of Li 2 CO 3 /year] positions the MPSE based technology within the reach of community investors, thus offering a paradigm shift in the development of critical technologies. The project successfully navigated two primary challenges: solvent selection and manufacturing adaptation. Restricted by the SOPO to existing literature for lithium recovery, the team identified a critical need for a "material excellence program" to develop next-generation solvents, eventually concluding with a preliminary investigation into promising Ionic Liquids (ILs). Simultaneously, COVID-19 supply chain disruptions forced a pivot from traditional manufacturing to advanced additive methods at ATAMI-OSU. By transitioning from stainless steel to 3D-printed polymer substrates, the team achieved a transformative three-order-of- magnitude reduction in manufacturing costs and compressed prototyping timelines from several months to just two days. The MPSE technology offers significant energy, environmental, and economic advantages by overcoming the traditional bottlenecks of phase-separation hardware and contactor size. Unlike conventional mixer-settlers or membrane-based systems, MPSE operates without moving parts or fouling-prone membranes, achieving robust performance even with challenging, viscous, or particulate-heavy feeds. Key performance metrics include an energy intensity reduction of 5–50x (3–40 kJ/m 3 ) compared to incumbent technologies and a dramatic reduction of processing time to under 60 seconds, which drastically reduces the physical plant footprint. These technical efficiencies translate into superior economic outcomes; for a 100 t/year Li 2 CO 3 facility, implementing MPSE is projected to nearly halve contactor CAPEX (from $\$$6.08M to $\$$3.01M) and significantly increase the project's Net Present Value (NPV), derisking new investment and enabling distributed critical-mineral processing configurations. The commercialization of MPSE technology is being spearheaded by Vigsur Dynamics Inc., which has adopted a structured, parallel approach to technical and business development since its formation in January 2026. Following extensive customer discovery and engagement with the Oregon State University accelerator, Vigsur Dynamics is working to establish a business model that transitions from pilot demonstrations to modular hardware sales, ultimately aiming for a "build-own-operate" service strategy. Current technical milestones—including 100 hours of continuous operation, superior energy efficiency, and successful 6-unit modular scale-up— provide a foundation for this transition. Backed by ongoing IP licensing and a growing network of industrial and venture advisors, the company is actively de-risking the platform to replace conventional mixer-settler systems in the critical minerals market.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Toward Lithium Recovery Using Modular (and Membraneless) Phase Separation and Extraction (MPSE) Technology with Ionic Liquid (IL) Solvents: Effect of Coatings

In this work, a single-channel slope-plate Modular and Membrane-less Phase Separation and Extraction (MPSE) device was fabricated using 3D printing. The slope-plate was designed with an insertable glass slide to enable surface modification with coatings. Self-assembled monolayers (SAMs) and perfluoropolyether (Zdol) coatings were applied to tailor surface wettability and enhance phase separation. Using a model biphasic system of water and hexadecane, both coatings significantly improved the separation efficiency compared to the uncoated device by promoting selective wetting. Building on these results, lithium extraction from a simulated saline solution was investigated using 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMIM][NTf₂]) as the ionic liquid (IL) extractant. The IL effectively extracted Li⁺ from the aqueous phase in bulk extraction, demonstrating its potential for lithium recovery. However, the low interfacial tension between the IL and aqueous phases posed challenges for phase separation. The application of SAM and Zdol coatings effectively mitigated this issue. Overall, integrating tailored surface chemistry with the slope-plate MPSE design shows great promise as an efficient and scalable platform for studying liquid–liquid separation and optimizing ionic liquid–based extraction processes for lithium recovery from saline sources.

3D printing↗

Integrated Circular Economy Model System for Direct Lithium Extraction: From Minerals to Batteries Utilizing Aluminum Hydroxide

Aluminum hydroxide, an abundant mineral found in nature, exists in four polymorphs: gibbsite, bayerite, nordstrandite, and doyleite. Among these polymorphs gibbsite, bayerite, and commercially synthesized amorphous aluminum hydroxide have been investigated as sorbent materials for lithium extraction from sulfate solutions. The amorphous form of Al(OH) 3 exhibits a reactivity higher than that of the naturally occurring crystalline polymorphs in terms of extracting Li + ions. This study employed high-temperature oxide melt solution calorimetry to explore the energetics of the sorbent polymorphs. The enthalpic stability order was measured to be gibbsite > bayerite > amorphous Al(OH) 3 . The least stable form, amorphous Al(OH) 3 , undergoes a spontaneous reaction with lithium, resulting in the formation of a stable layered double hydroxide phase. Consequently, amorphous Al(OH) 3 shows promise as a sorbent material for selectively extracting lithium from clay mineral leachate solutions. Further, this research demonstrates the selective direct extraction of Li + ions using amorphous aluminum hydroxide through a liquid–solid lithiation reaction, followed by acid-free delithiation and relithiation processes, achieving an extraction efficiency of 86%, and the maximum capacity was 37.86 mg·g –1 in a single step during lithiation. With high selectivity during lithiation and nearly complete recoverability of the sorbent material during delithiation, this method presents a circular economy model. Furthermore, a life cycle analysis was conducted to illustrate the environmental advantages of replacing the conventional soda ash-based precipitation process with this method, along with a simple operational cost analysis to evaluate reagent and fuel expenses.

25 ENERGY STORAGE↗

Structural regulation-induced Li-electron disentanglement for stabilized oxygen redox of Li-excess disordered rock-salt cathode materials

Since the discovery of its electrochemical activity, Li-excess disordered rock-salt (DRX) cathode material has received worldwide attention as it sets up a new way to exploit oxygen redox beyond the conventional layered structure with late-3d transition metals. However, the intricate structure-function relationship in the disordered lattice of the DRX material fogs the researcher's lens on the underlying redox mechanisms. Here, in this study, we employ a synergistic approach combining neutron total scattering with reverse Monte Carlo modeling and density functional theory calculations to unravel the landscape of oxygen redox reactions in DRX. Redox activities are evaluated in diverse oxygen clusters (OLi x TM 6-x ) and the spatial distribution of these clusters in the model DRX structure (Li 1.16 Ti 0.37 Ni 0.37 Nb 0.1 O 2 and Li 1.2 Ti 0.35 Ni 0.35 Nb 0.1 O 1.8 F 0.2 ) is explicitly determined. The results unveil that by regulating the short-range ordering between cations, fluorine atoms can effectively decouple the location of Li extraction and electron depletion. Such disentanglement between the Li reservoir and electron reservoir in the DRX lattice could play a pivotal role in protecting the oxidized oxygen and preserving the lattice framework during cycling. Through a tentatively designed non-fluorinated DRX oxide realizing similar Li-electron decoupling, an obvious enhancement of the cycling capability can be achieved without compromising the capacity release.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Fluorinated Rocksalt Cathode with Ultra‐high Active Li Content for Lithium‐ion Batteries

Abstract The key to increasing the energy density of lithium‐ion batteries is to incorporate high contents of extractable Li into the cathode. Unfortunately, this triggers formidable challenges including structural instability and irreversible chemistry under operation. Here, we report a new kind of ultra‐high Li compound: Li 4+ x MoO 5 F x (1≤ x ≤3) for cathode with an unprecedented level of electrochemically active Li (>3 Li + per formula), delivering a reversible capacity up to 438 mAh g −1 . Unlike other reported Li‐rich cathodes, Li 4+ x MoO 5 F x presents distinguished structure stability to immunize against irreversible behaviors. Through spectroscopic and electrochemical techniques, we find an anionic redox‐dominated charge compensation with negligible oxygen release and voltage decay. Our theoretical analysis reveals a “reductive effect” of high‐level fluorination stabilizes the anionic redox by reducing the oxygen ions in pure‐Li conditions, enabling a facile, reversible, and high Li‐portion cycling.

Pei, Yi↗

Fluorinated Rocksalt Cathode with Ultra-high Active Li Content for Lithium-ion Batteries

The key to increasing the energy density of lithium-ion batteries is to incorporate high contents of extractable Li into the cathode. Unfortunately, this triggers formidable challenges including structural instability and irreversible chemistry under operation. Here, we report a new kind of ultra-high Li compound: Li 4+x MoO 5 F x (1≤x≤3) for cathode with an unprecedented level of electrochemically active Li (>3 Li + per formula), delivering a reversible capacity up to 438 mAh g –1 . Unlike other reported Li-rich cathodes, Li 4+x MoO 5 F x presents distinguished structure stability to immunize against irreversible behaviors. In this work, through spectroscopic and electrochemical techniques, we find an anionic redox-dominated charge compensation with negligible oxygen release and voltage decay. Our theoretical analysis reveals a “reductive effect” of high-level fluorination stabilizes the anionic redox by reducing the oxygen ions in pure-Li conditions, enabling a facile, reversible, and high Li-portion cycling.

36 MATERIALS SCIENCE↗

Magnetic Nanoparticle Extraction of Lithium from Produced Waters: CRADA 483 [Abstract only]

In this project, we will synthesize, evaluate, and screen a set of new sorbents that have high capacity and selectivity for lithium. Sorbent performance will be evaluated by conducting Li extraction tests with produced water samples supplied by ConocoPhillips Company, Moselle Technologies, and Cascade Natural Resources. The best performing of these sorbents based on Li uptake capacity and selectivity will be produced as a magnetic nanoparticle and subjected to extended cycle testing in our laboratory bench-scale magnetic separator system. Moselle has acquired an exclusive license to the background IP associated with this magnetic nanoparticle mineral extraction technology and wishes to foster implementation of the technology in the oil & gas industry through this CRADA. Moselle will support PNNL in the design of a commercial-scale magnetic separator system tailored for lithium production. The goal is to collect sufficient information to support a decision by our industry partners to invest in a subsequent field demonstration at one of our partner’s field sites as a prerequisite to advancing this technology towards commercialization.

36 MATERIALS SCIENCE↗

Investigating Ternary Li–Mg–Si Zintl Phase Formation and Evolution for Si Anodes in Li-Ion Batteries with Mg(TFSI) 2 Electrolyte Additive

Improved electrochemical performance of Si was recently reported by adding multivalent cation salts (such as Mg 2+ , Al 3+ , Ca 2+, etc.) in the electrolyte. This is achieved via the formation in an in situ manner of relatively more stable Li-M-Si ternary phases with less chemical reactivity. These phases stabilize Si anions and thus reduce side reactions with electrolytes at the surface and eventually benefit the overall electrochemistry. To understand the mechanism of ternary Zintl phase formation and its dynamics upon lithiation/delithiation, high-resolution solid-state 7 Li and 29 Si nuclear magnetic resonance (NMR) are utilized to directly probe the local Li and Si environments on Si electrodes harvested from coin and pouch cells at various states of (de)lithiation. The NMR spectra along with the electrochemical characterization reveal that lithiation of Si starts from the surface Si-O layer further confirmed by 7 Li– 29 Si cross-polarization NMR. Lithiation progresses with heterogeneous silicon clustering with Si -4 anions at high states of lithiation. At a fully lithiated state, the formation of overlithiated Si species is detected. At a low-voltage region (below 100 mV), direct evidence for Mg-ion insertion is found, postulated by two possible mechanisms: ion exchange with fully or overlithiated binary domains (Li 3.75+x Si) and/or a coinsertion with slightly underlithiated domains (similar to Li 3.55 Si). Upon delithiation, Li extraction starts from overlithiated Si domains. No evidence is found for electrochemical Mg removal. Evidence for a lithium-deficient Li y Mg 0.1 Si phase is found as a result of Li removal during charging. This investigation sheds light on the possible mechanisms of a new Si anode chemistry, which could enable the development of stable Si-based anodes for lithium-ion batteries.

25 ENERGY STORAGE↗

Mechanochemically Robust LiCoO 2 with Ultrahigh Capacity and Prolonged Cyclability

Pushing intercalation-type cathode materials to their theoretical capacity often suffers from fragile Li-deficient frameworks and severe lattice strain, leading to mechanical failure issues within the crystal structure and fast capacity fading. This is particularly pronounced in layered oxide cathodes because the intrinsic nature of their structures is susceptible to structural degradation with excessive Li extraction, which remains unsolved yet despite attempts involving elemental doping and surface coating strategies. Herein, a mechanochemical strengthening strategy is developed through a gradient disordering structure to address these challenges and push the LiCoO 2 (LCO) layered cathode approaching the capacity limit (256 mAh g -1 , up to 93% of Li utilization). This innovative approach also demonstrates exceptional cyclability and rate capability, as validated in practical Ah-level pouch full cells, surpassing the current performance benchmarks. Comprehensive characterizations with multiscale X-ray, electron diffraction, and imaging techniques unveil that the gradient disordering structure notably diminishes the anisotropic lattice strain and exhibits high fatigue resistance, even under extreme delithiation states and harsh operating voltages. Consequently, this designed LCO cathode impedes the growth and propagation of particle cracks, and mitigates irreversible phase transitions. In conclusion, this work sheds light on promising directions toward next-generation high-energy-density battery materials through structural chemistry design.

36 MATERIALS SCIENCE↗

Porosity Development at Li-Rich Layered Cathodes in All-Solid-State Battery during In Situ Delithiation

Structural evolutions are crucial for determining the performance of high-voltage lithium, manganese-rich layered cathodes. Moreover, interface between electrode and electrolyte plays a critical role in governing ionic transfer in all-solid-state batteries. In this work, we unveil two different types of porous structure in Li 1.2 Ni 0.2 Mn 0.6 O 2 cathode with LiPON solid-state electrolyte. Na-nopores are found near the cathode/electrolyte interface at pristine state, where cation mixing, phase transformation, oxygen loss and Mn reduction are also found. In situ Li + extraction induces the evolution of nanovoids, initially formed near the inter-face then propagated into the bulk. Despite the development of nanovoids, layered structure is conserved, suggesting the nature of nanopores and nanovoids are different and their impact would be divergent. This work demonstrates the intrinsic interfacial layer, as well as the dynamic scenario of nanovoid formation inside high-capacity layered cathode, which help understanding the performance fading in cathodes and offer insights into the all-solid-state battery design.

25 ENERGY STORAGE↗

Definition of Redox Centers in Reactions of Lithium Intercalation in Li 3 RuO 4 Polymorphs

Cathodes based on layered LiMO 2 are the limiting components in the path toward Li-ion batteries with energy densities suitable for electric vehicles. Introducing an over-stoichiometry of Li increases storage capacity beyond a conventional mechanism of formal transition metal redox. However, the role and fate of the oxide ligands in such intriguing additional capacity remain unclear. This reactivity was predicted in Li 3 RuO 4 , making it a valuable model system. For this study, a comprehensive analysis of the redox activity of both Ru and O under different electrochemical conditions was carried out, and the effect of Li/Ru ordering was evaluated. Li 3 RuO 4 displays highly reversible Li intercalation to Li 4 RuO 4 below 2.5 V vs Li + /Li 0 , with conventional reactivity through the formal Ru 5+ -Ru 4+ couple. In turn, it can also undergo anodic Li extraction at 3.9 V, which involves O states to a much greater extent than Ru. This reaction competes with side processes such as electrolyte decomposition and, to a much lesser extent, oxygen loss. Although the associated capacity is reversible, reintercalation unlocks a different, conventional pathway also involving the formal Ru 5+ -Ru 4+ couple despite operating above 2.5 V, leading to chemical hysteresis. This new pathway is both chemically and electrochemically reversible in subsequent cycles. This work exemplifies both the challenge of stabilizing highly depleted O states, even with 4d metals, and the ability of solids to access the same redox couple at two very different potential windows depending on the underlying structural changes. It highlights the importance of properly defining the covalency of oxides when defining charge compensation in view of the design of materials with high capacity for Li storage.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Mixed Cationic and Anionic Redox in Ni and Co Free Chalcogen-Based Cathode Chemistry for Li-Ion Batteries

Mixed cationic and anionic redox cathode chemistry is emerging as conventional cationic-redox of transition metal based layered oxides are reaching their theoretical capacity limit. However, these anionic redox in transition metal oxide-based cathodes attained by taking excess lithium has resulted in stability issues due to weak metal - oxygen ligand covalency. Here, we present an alternative approach of improving metal - ligand covalency by introducing less electronegative chalcogen ligand (sulfur) in the cathode structural framework where the metal dband penetration into ligand p-band thereby utilizing reversible mixed anionic and cationic redox chemistry. Through this design strategy, we report possibility of developing a new family of layered cathode materials when partially filled d orbital redox couples like Fe 2+/3+ are introduced in the Li-ion conducting phase (Li 2 SnS 3 ). Further, the electron energy loss spectroscopy (EELS) and X-ray absorption near-edge structure (XANES) analysis are used to qualitatively identify the charge contributors at the metal and ligand sites during Li + extraction. The detailed high-resolution transmission electron microscopy (HR-TEM) and high annular dark field-scanning transmission electron microscopy (HAADF-STEM) investigation reveal the multi redox induced structural modifications and its surface amorphization with nanopore formation during cycling. Findings from this study will shed light on designing Ni and Co free chalcogen cathodes and various functional materials in the chalcogen based dual anionic and cationic redox cathode avenue.

25 ENERGY STORAGE↗

A multi-technique approach to understanding delithiation damage in LiCoO2 thin films

Abstract We report on the delithiation of LiCoO 2 thin films using oxalic acid (C 2 H 2 O 4 ) with the goal of understanding the structural degradation of an insertion oxide associated with Li chemical extraction. Using a multi-technique approach that includes synchrotron radiation X-ray diffraction, scanning electron microscopy, micro Raman spectroscopy, photoelectron spectroscopy and conductive atomic force microscopy we reveal the balance between selective Li extraction and structural damage. We identify three different delithiation regimes, related to surface processes, bulk delithiation and damage generation. We find that only a fraction of the grains is affected by the delithiation process, which may create local inhomogeneities. However, the bulk delithiation regime is effective to delithiate the LCO film. All experimental evidence collected indicates that the delithiation process in this regime mimics the behavior of LCO upon electrochemical delithiation. We discard the formation of Co oxalate during the chemical extraction process. In conclusion, the chemical route to Li extraction provides additional opportunities to investigate delithiation while avoiding the complications associated with electrolyte breakdown and simplifying in-situ measurements.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗