Lithium Battery Cathode Research Articles

A Case Study of an Energy Barrier in Li-Ion Battery Cathode Material Using DFT and Post-HF Approaches.

With the ever-increasing interest toward energy storage materials, an accurate understanding of the underlying physicochemical processes becomes mandatory for enabling accurate and predictive simulations. In this study, we apply multilevel quantum chemical calculations on a benchmark material commonly adopted as a cathode in Lithium batteries, Li0.5Co0.5+3Ni0.5+4O2. We estimate the Lithium hopping barrier, a key quantity for the estimate of Li diffusion coefficient, at different levels: Hartree-Fock (HF), density functional theory (DFT), periodic local Møller-Plesset perturbation theory of second order, complemented with a coupled cluster correction evaluated using an embedded-fragment approach. The post-HF methods were used here not only for benchmarking the key quantities themselves but also for assessing the accuracy of different functionals and probing the influence of the long-range and static correlation. For the given system and quantity in question, we observe that obtained results do not significantly vary across different DFT functionals or post-HF methods, which is rather uncommon. Such an agreement between the employed methods suggests that static correlation, even if prominent in this system, cancels out in the studied energy differences. In fact, the values of the T1 diagnostics, which test the reliability of the single-reference description, do vary from one fragment to another. But for certain fragments they are fairly small and of similar magnitude, indicating the applicability of such fragments for the correction. Our best estimate of the reaction barrier is about 0.85 eV.

Design and synthesis of FeS2/graphite sandwich structure with enhanced lithium-storage performance for lithium-ion and solid-state lithium batteries

As a conversion-type cathode material, FeS2 emerges as a promising candidate for the next generation of energy storage solutions, attributed to its cost-effectiveness, environment-friendliness and high theoretical capacity. However, several challenges hinder its practical application, including sluggish kinetics, insulating reaction products and significant volume fluctuation during cycling, which collectively compromise its rate capability and cycle stability. Herein, a well-designed sandwich structure of FeS2 embedded between graphite layers (FeS2/C) is obtained using a chloride intercalation and sulfidation strategy. The layered graphite-FeS2-graphite configuration boosts the active sites and adsorption capacity of Li+, thereby guaranteeing a high reversible capacity. Furthermore, the graphitic carbon matrix serves a dual purpose: it enhances electronic conductivity and restrain the volume fluctuation of FeS2 during long cycling. This combination ensures robust electrochemical kinetics, structural integrity and long life. Consequently, the FeS2/C composites exhibit exceptional lithium storage performance, achieving capacities of 506.2 mAh g−1 at 0.5 A/g and 277.2 mAh g−1 at 5.0 A/g. Additionally, the FeS2/C composites show promising potential as cathodes for all solid-state lithium batteries, showcasing high specific capacities of 658.0 mAh g−1 at 0.1 A/g for the second cycle and maintaining a cycle performance of 288.5 mAh g−1 after 800 cycles at 0.5 A/g. These values surpass the second discharge specific capacity of 96.1 mAh g−1 and cycle capacity of 25.3 mAh g−1 observed for Fe2O3/C composites. The discharge mechanism of FeS2/C composites was further characterized through in-situ transmission electron microscope test. This work provides valuable insights for designing and synthesizing FeS2, highlighting its potential for lithium ion storage and all solid-state lithium batteries.

Machine learning descriptors for crystal materials: applications in Ni-rich layered cathode and lithium anode materials for high-energy-density lithium batteries

Lithium batteries have revolutionized energy storage with their high energy density and long lifespan, but challenges such as energy density limitations, safety, and cost still need to be addressed. Crystalline materials, including Ni-rich cathodes and lithium anodes, play pivotal roles in the performance of high-energy-density lithium batteries. Understanding the micro-scale behavior and degradation mechanisms of these materials is crucial for improving macro-scale battery performance. Simulation methods, particularly machine learning (ML) techniques, have become indispensable tools in elucidating these intricate processes because of great efficiency and acceptable accuracy. ML methods depend on descriptors, which bridge the gap between crystal structures and input matrices of models. These descriptors encode essential atomic-level details in crystal structures, enabling predictions of material properties and behaviors relevant to lithium batteries. This paper reviews and discusses the diverse array of descriptors employed in the simulation of crystalline materials for lithium batteries with high energy density. Case studies highlight the effectiveness of different descriptors in simulating cathode behaviors such as Li/Ni disordering, screening of stable LiNi0.8Co0.1Mn0.1O2 (NMC811) configurations, and lithium deposition behaviors at the anode interface. The discussed descriptors can also be applied to other crystalline cathode, anode, and electrolyte materials in lithium batteries and advance the development of lithium batteries with superior energy density.

Fluorinated functional groups enhanced composite in-situ gel electrolytes for high voltage cathode of quasi solid-state lithium battery

Gel electrolyte is an ideal system for improving the cycling stability and safety of lithium metal battery. However, traditional gel system with acrylic ester system is still not suitable for high-voltage battery system limited by its intrinsic structure and unstable interface. The polymer structures with -CF3 modified acrylic ester are proposed to improve the stability of both structure and interface in high-voltage battery systems. The LiF-rich anode-electrolyte interface assisted by fluorine contained in-situ gel electrolyte ensures stable cycling of lithium anode. The quasi-solid state lithium battery assembled with the LiFePO4 can still achieve a capacity retention rate of 81.2 % after 900 cycles at a rate of 1 C. Furthermore, the uniform organic cathode-electrolyte interface constructed by crosslinked -CF3 modified polymer effectively inhibits the corrosion of HF on the cathode material. The interaction between the anion and solvent molecules prevents the continuous decomposition reaction of the electrolyte on the surface of the LiCoO2 cathode at high voltage, which guarantees LiCoO2 battery can still achieve a capacity retention rate of 82.1 % after 500 cycles at a voltage of 4.45V. Design of fluorine contained in-situ polymer gel electrolyte could promote the development of quasi solid-state battery in practical industrial application.

Ultra-high rate performance of single-crystalline NMC cathodes enabled by a TEP-based electrolyte

Harnessing the full potential of Ni-rich single-crystal cathodes (LiNixMnyCo1-x-yO2, NMC) for next-generation high-energy lithium batteries is hindered by their slow reaction kinetics and susceptibility to interfacial decay. Our research introduces a novel strategy utilizing triethyl phosphate (TEP) and fluoroethylene carbonate (FEC) to optimize the Li+ solvation environment, lowering the coordination number and diminishing the energy threshold for Li+ transport. Mechanistic studies indicate that this intervention not only accelerates the Li+ transfer at the electrode/electrolyte interface but also catalyzes the development of a robust LiF-rich CEI layer. As a result, the single-crystal NMC83 cathode exhibits remarkable high-rate discharge capacities of approximately 209 mAh g−1 at 0.1 C and 192 mAh g−1 at 0.5 C. The robust CEI layer also mitigates parasitic reactions, substantially improving the cycle life, with capacity retention increasing from 46.1 % to 88.2 % after 300 cycles at 1 C. This work underscores the transformative impact of solvation sheath engineering on the interfacial dynamics of single-crystal cathodes, paving the way for more durable and efficient energy storage solutions.

2D Covalent Organic Framework Covalently Anchored with Carbon Nanotube as High-Performance Cathodes for Lithium and Sodium-Ion Batteries.

Covalent organic frameworks (COFs), featuring structural diversity, permanent porosity, and functional versatility, have emerged as promising electrode materials for rechargeable batteries. To date, amorphous polymer, COF, or their composites are mostly explored in lithium-ion batteries (LIBs), while their research in other alkali metal ion batteries is still in infancy. This can be due to the challenges that arise from large volume changes, slow diffusion kinetics, and inefficient active site utilization by the large Na+ or K+ ion. Herein, microwave-assisted imide-based 2D COF, TAPB-NDA covalently connected with amine-functionalized carbon nanotubes (TAPB-NDA@CNT) targeting the application in both Li-/Na-ion batteries, is synthesized. As-synthesized, TAPB-NDA@CNT50 displays the good performance as LIB cathode with a specific capacity of ≈138mAhg-1 at 25mAg-1, long cycling stability (81.2% retention after 2000 cycles at 300mAg-1), with excellent reversible capacity retention of ≈79.6%. Similarly, TAPB-NDA@CNT50, when employed in sodium-ion battery (SIB), exhibited 136.7mAhg-1 specific capacity at 25mAg-1, retained ≈80% of the reversible capacity after 1000 cycles at 300mAg-1 and showing excellent rate performance. The structural advantage of TAPB-NDA@CNT will encourage researchers to design COF-based cathodes for the alkali ion batteries.

Predicting Effective Transport Properties of Randomly Oriented Polycrystalline Li-Ion Battery Electrodes

Widely practiced Li-ion battery models, such as pseudo-two-dimensional (P2D) models [1-3], use representative spherical electrode particles with assumed isotropic transport properties. Electrode particles, such as NMC, are typically composites that are comprised of numerous randomly oriented crystallites. Each of the single-crystal primary particles that compose secondary particle can have strongly anisotropic transport properties that affect the intercalation process. The empirically approximated effective properties (e.g., diffusion coefficients) as reported in literature vary by as much as six orders of magnitude. In many cases, the effective diffusion coefficients are determined as a part of a parameter-fitting procedure to represent battery polarization measurements.The present approach develops both analytical and computational homogenization methods that derive effective properties based upon the intrinsic single-crystal properties of the crystallites. Homogenization techniques are computationally effective methods to predict macroscale behavior based on microscale properties.As illustrated in Fig. 1, the computational approach begins by assembling over 1000 randomly oriented single-crystal primary particles, with each crystallite having anisotropic properties associated with the crystal lattice. The dodecahedron-shaped primary particles are tightly assembled into a secondary particle that is approximately spherical. A three-dimensional finite-element model predicts transient Li-intercalation fractions throughout a secondary particle during charge or discharge processes. In graphite, the transverse and normal diffusion coefficients differ by approximately six orders of magnitude. Based on the cut plane in Fig. 1, and despite extreme anisotropy within the crystallites, the homogenized macroscopic behavior is nearly isotropic.The analytical approach extends a self-consistent method (SCM) for polycrystalline materials first presented by Ponte-Castañeda and Willis [4], which mathematically combines tensors describing diffusion pathways for every primary particle. The present study considers the concentration-dependent and anisotropic diffusion parameters collected by Persson et al. [5] and Zhou et al. [6] for graphite and NMC, respectively. Another homogenization method is the use of an orientation distribution function (ODF) [7], which predicts the effective diffusion parameters based on the statistical average of every possible primary particle orientation. Fig. 2 shows the predicted effective diffusion coefficients bounded by Hashin-Shtrikman bounds for anisotropic composites proposed by Willis [8] and the experimentally determined diffusion coefficients. The predicted effective diffusion coefficients are lower than the experimentally determined values in transverse direction but are significantly larger than the values in the normal direction. Additionally, the in-plane diffusion dominates the curvature of the predicted effective properties.[1] M. Doyle, T. F. Fuller, and J. Newman. Modeling of galvanostatic charge and discharge of the lithium/polymer/insertion cell. J. Electrochem. Soc., 140:1526–1533, 1993.[2] T. F. Fuller, M. Doyle, and J. Newman. Simulation and optimization of the dual lithium ion insertion cell. J. Electrochem. Soc., 141:1–10, 1994.[3] M. Doyle, J. Newman, A. S. Gozdz, C. N. Schmutz, and J.-M. Tarascon. Comparison of modeling predictions with experimental data from plastic lithium ion cells. J. Electrochem. Soc., 143:1890–1903, 1996[4] P.P.- Castañeda and J.R. Willis. The effect of spatial distribution on the effective behavior of composite materials and cracked media. J. Mech. Phys. Solids, 43:1919–1951, 1995[5] K. Persson, V. A. Sethuraman, L. J. Hardwick, Y. Hinuma, Y. S. Meng, A. van der Ven, V. Srinivasan, R. Kostecki, and G. Ceder. Lithium diffusion in graphitic carbon. J. Phys. Chem. Lett., 1:1176–1180, 2010[6] H. Zhou, F. Xin, B. Pei, and M. S. Whittingham. What limits the capacity of layered oxide cathodes in lithium batteries? ACS Energy Lett., 4:1902–1906, 2019[7] S. Nemat-Nasser, M. Hori, and J. D. Achenbach. Micromechanics: Overall properties of heterogeneous materials. In Micromechanics, volume 37. Elsevier Science I& Technology, The Netherlands, 1993[8] J.R. Willis. Bounds and self-consistent estimates for the overall properties of anisotropic composites. J. Mech. Phys. Solids, 25:185–202, 1977 Figure 1

Electrolytic recovery of metals from lithium battery cathodes in moisture-tolerant molten hydroxide salt

Lithium-ion battery recycling offers an opportunity to develop innovative technologies to close the loop on the battery materials cycle and increase the resilience of the battery supply chain. Here we demonstrate a two-step pyroelectrochemical method for producing mixed-metals from lithium-ion cathodes in a molten hydroxide salt. Mixed metal oxides in the form of insoluble lithium-ion cathode materials of LiNi0.6Mn0.2Co0.2O2 (NMC622) and spent lithium-ion battery materials (black mass) were electrochemically reduced to a soluble form and dissolved into a molten hydroxide salt bath. Electrochemical characterization of the process salt indicated accumulation of dissolved transition metals in the salt. A separate cathode was used to produce alloys of Ni, Mn, and Co electrochemically from the dissolved lithium-ion cathode materials. Characterization by scanning electron microscopy fitted with an energy dispersive X-ray spectrometer showed transition metals present in the cathode materials were recovered at the separate cathode. This approach represents a scalable, low temperature pyroelectrochemical process that can potentially reduce the cost and close the loop of battery cathode recycling.

A universal strategy towards high-rate and ultralong-life of Li‐rich Mn‐based cathode materials

Lithium-rich manganese-based cathode materials (LRMs) have shown promise for the next-generation lithium battery cathodes due to their high discharge specific capacity (∼250 mAh g−1) and wide operating voltage range (2.0–4.8 V). However, these materials face limitations such as low initial Coulombic efficiency (ICE), poor cycle stability, and inadequate rate capability. To address these challenges, we employed a simple citric acid treatment (CA-treatment) method to fabricate the Li-rich spinel coating layer on LRMs. This in situ formed spinel Li4Mn5O12 layer successfully suppresses the oxygen release, provides three-dimensional (3D) lithium-ion diffusion channels and enriches Li embedding sites, resulting in a substantial improvement in the rate capability and high-rate cycling performance. The modified LRM delivers a high specific capacity of 193.7 mAh g−1 at 2.0 C and 154.8 mAh g−1 at 5.0 C, after 1000 cycles at 10.0 C, 77.4 % capacity retention with 102.5 mAh g−1 is realized. This facile CA-treatment benefits the electrochemical properties of LRMs comparable to those of altering the microscopic morphology. This work offers a new avenue for exploring outstanding LRMs with high-rate and ultralong cycling life.

Simultaneous exfoliation/fluorination for the preparation of fluorinated exfoliated graphite with high power densities in primary lithium batteries

Fluorinated carbons combining accordion-like morphology, high content of (C2F)n phase (43%), and residual non-fluorinated carbons were synthetized by two routes, i.e. fluorination of expanded graphite and simultaneous exfoliation/fluorination of expandable graphite. The latter allows the synthesis in a one-step process to be achieved. Accordion-like morphology allows the accommodation of LiF without detrimental accumulation onto the fluorocarbon sheet edges during the discharge in primary lithium battery. The faradic yield is then close to 100 % up to a discharge rate of 6C. Residual sp2 carbons (sub-fluorination) ensure the electron flux during the electrochemical process and enhance the power density (9828 W.Kg-1). High content of (C2F)n phase results in a flat galvanostatic discharge curve. The combination of those features results in a good compromise between energy and power densities, making fluorinated exfoliated graphite one of the best cathodes for primary lithium batteries.

Exceptional Rate Performances of Li-Rich Mn-Based Cathodes Enabled by Boron-Based Additives-Driven Self-Optimized Interface.

Li-rich Mn-based cathode material (LRM), as a promising cathode for high energy density lithium batteries, suffers from severe side reactions in conventional lithium hexafluorophosphate (LiPF6)-based carbonate electrolytes, leading to unstable interfaces and poor rate performances. Herein, a boron-based additives-driven self-optimized interface strategy is presented to dissolve low ionic conductivity LiF nanoparticles at the outer cathode electrolyte interface, leading to the optimized interfacial components, as well as the enhanced Li ion migration rate in electrolytes. Being attributed to these superiorities, the LRM||Li battery delivers a high-capacity retention of 92.19% at 1C after 200 cycles and a low voltage decay of 1.08 mV/cycle. This work provides a new perspective on the rational selection of functional additives with an interfacial self-optimized characteristic to achieve a long lifespan LRM with exceptional rate performances.

LiMn0.8Fe0.2PO4 as a promising cathode material in solid-state lithium batteries: Structural and electrical characterization

In this study, the synthesis, structural characterization, and electrical property analysis of LiMn0.8Fe0.2PO4 (LM8F) and its carbon-composite variant (LM8F-10%C) as potential cathode materials for solid-state lithium batteries were reported. Employing high-energy ball milling (HEBM) followed by calcination, LM8F was synthesized using ammonium dihydrogen phosphate, lithium carbonate, manganese(II) acetate tetra-hydrate, and iron(III) phosphate as precursors. The introduction of glucose as a carbon source aimed at the formation of a carbon-coated composite to enhance the electrical conductivity of the material. Structural and morphological characteristics of the synthesized materials were elucidated through X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and field emission scanning electron microscopy (FeSEM). The XRD results confirmed the olivine and orthorhombic structure of the synthesized material, highlighting its suitability for use as a cathode in solid-state lithium batteries. Electrical properties were assessed using an LCR meter to examine the impact of carbon coating on electrochemical performance. The findings demonstrated that the inclusion of carbon significantly improved the electrical conductivity, potentially leading to enhanced battery performance. This work contributes to the development of high-performance cathode materials for solid-state lithium batteries, paving the way for future advancements in energy storage technologies.

Surface-to-bulk engineering with high-valence W6+ enabling stabilized single-crystal LiNi0.9Co0.05Mn0.05O2 cathode

Single-crystal Nickel-rich layered oxides has been recognized as one of the promising cathodes for next-generation lithium batteries on account of their high capacity, while its practical application was hindered by structural instability and slow Li+ transfer kinetics. Herein, a surface-to-bulk engineered single-crystal LiNi0.9Co0.05Mn0.05O2 (Ni90) cathode, which features W-doped bulk and Li2WO4 surface layer, was successfully achieved by a one-step high-valence W6+ modification. The as-obtained W-modified Ni90 delivers excellent cycling stability (89.8% capacity retention after 300 cycles at 0.5 C) and rate capability. The enhanced electrochemical performance was ascribed to the doped-W induced stabilized lattice oxygen, reduced Li+/Ni2+ mixing and inhibited H2-H3 phase transition in the bulk, and Li2WO4 layer generated stabilized cathode/electrolyte interface. In addition, the thinner LiF-rich cathode electrolyte interphase (CEI) on surface and smaller grain size for W-modified Ni90 benefit to its Li+ diffusion dynamics. The effect of high-valence W6+ on single-crystal Ni-rich cathode was firstly revealed in detail, which deepens the understanding of electrochemical behavior of Ni-rich cathode with high-valence cations modification, and provides clues for design of high-performance layered cathodes.

Durable Sb/Na co-doped lithium-rich cathode material prepared by a novel planetary griding method

Nano-sized cathode materials are recognized for their enhanced active reaction area and uniform chemical composition, leading to distinct electrochemical performance benefits. However, the conventional sol–gel methods used for nanomaterial synthesis are often marred by significant raw material wastage and lengthy preparation processes, limiting their practicality. This study introduces a straightforward planetary grinding approach using low-melting-point precursors for the synthesis of oxide cathodes for lithium batteries. Through this method, an antimony and sodium co-doped lithium-rich layered oxide was produced, showcasing an impressive specific capacity of 238.48 mAh/g at a current density of 0.2 C (50 mA/g). Furthermore, this material exhibited outstanding cycle performance, maintaining 97.5 % capacity retention after 500 cycles at 1 C, with a specific capacity of 190.54 mAh/g in the final cycle.

Promoted production of aromatic hydrocarbons in biomass catalytic pyrolysis over the coupled catalysts of carbon-reduced waste lithium battery cathode materials and HZSM-5

Inexpensive catalyst sources are of great importance in the conversion of biomass to economically valuable monocyclic aromatic hydrocarbons, and transition metals (Co, Ni, Fe and Mn) rich in catalytic effects in massive waste lithium battery cathode materials are not effectively reutilized currently. For this reason, the feasibility of employing the valuable metal oxides in the carbon-reduced waste lithium battery cathode materials (waste LiFePO4 batteries, LFP, and waste LiNixCoyMn1–x–yO2 batteries, NCM) with HZSM-5 as coupled catalysts in the rape straw catalytic pyrolysis to produce aromatic hydrocarbons was explored. The carbon-reduced waste lithium battery cathode materials performed well at 5 wt% carbon loading, and the content of active components Fe2O3 (SLFPC-5) and NiO (SNCMC-5) used for the reduction of large molecular oxygenates in biomass pyrolysis gas was increased by water leaching treatment. SLFPC-5 demonstrated superior bond-cutting performance, while SNCMC-5 exhibited strong deoxygenation performance. The selectivity of monocyclic aromatic hydrocarbons (MAHs) catalyzed by SLFPC-5/HZSM-5 and SNCMC-5/HZSM-5 was as high as 63.69 % and 79.19 %, with BTX yields of 14.58 wt% and 16.68 wt% respectively. This coupled catalytic system offers a low-cost source of catalysts for biomass catalytic pyrolysis and broadens the possibility of high-value recycling of wasted lithium batteries.

Enhanced lithium battery cathode performance via mechanical grinding of CFx_MnO2 hybrid materials for space-grade applications: Unveiling synergistic effects

CFx_MnO2 hybrid cathode materials are prepared from a (C2F)n-type graphite fluoride (CFx) and industrial MnO2. Because of its physicochemical (insulating behavior, low content of CF2 and CF3 groups, no or a few remaining sp2 carbon atoms) and electrochemical properties (flat plateau on galvanostatic curve and theoretical capacity of 623 mAh/g, higher than other conventional cathodes for primary lithium battery), graphite fluoride of (C2F)n-type is selected to evidence synergetic effects with MnO2 that occur at the fluoride/oxide and electrolyte/ electrode interfaces. Both materials are mixed by mechanical ball-milling using different sets of parameters. The hybrid material presents very good electrochemical properties with a maximum energy density of about 1600 Wh per kg of active material. Notably, it shows a considerable improvement in voltage plateau and voltage delay compared to CFx. The parameters applied during ball-milling also shape the electrochemical performance of the new hybrid material. Ball milling increases the average discharge voltage plateau, and the power density of the battery, and avoids ohmic drop which may cause a battery to be eliminated as soon as it begins to discharge. More finely, electrochemical impedance spectroscopy shows that pushed grinding leads to more homogeneous but more polarized material-electrolyte interfaces so better diffusion and capacity but lower discharge potential.

LaCoO3@Fe3O4 as peroxymonosulfate activator derived from spent lithium battery cathode materials for degradation of sulfamethoxazole in water

To reduce the various hazards of SMX to aquatic ecosystems, in this study, magnetically separable LaCoO3@Fe3O4 catalysts for the degradation of sulfamethoxazole (SMX) in water by activated peroxymonosulfate (PMS) were successfully prepared by using cobalt oxalate recovered from spent batteries using sol–gel, hydrothermal, and high-temperature calcination methods. The main factors influencing the reaction and the effect of coexisting ions on the degradation efficiency of SMX were investigated. The results showed that under optimal conditions ([SMX] = 30 mg, [LaCoO3@Fe3O4] = 10 mg/L, [PMS] = 30 mg/L, pH (initial) = 7.02), the LaCoO3@Fe3O4/PMS system degraded SMX up to 93 % in 15 min. The degradation of SMX in the LaCoO3@Fe3O4/PMS system was shown to be achieved by a combination of radical (SO4•-/•OH/•O2–) and non-radical (1O2) pathways by quenching experiments and electron paramagnetic resonance spectroscopy (EPR) analysis. Then, three possible degradation pathways were proposed using LC-MS, and Ecological Constitutive Relationship (ECOSAR) analysis showed that the toxicity of the intermediate products was all lower than that of SMX, indicating that the system is feasible for SMX degradation. This study provides a new idea for activating PMS for the degradation of antibiotics in water by preparing catalysts using precious metals from recycled batteries.

Eco-friendly closed-loop recycling of nickel, cobalt, manganese, and lithium from spent ternary lithium-ion battery cathodes

Recycling technology is essential for managing waste and addressing environmental issues related to scrapping power lithium batteries. A closed-loop recycling technique was proposed in this work for maximizing usage of lithium (Li), manganese (Mn), cobalt (Co), and nickel (Ni) resources in spent ternary lithium battery (SNCMB) cathodes. A green and sustainable leaching process utilizes citric acid (CA) and hydrogen peroxide (HP) to efficiently extract Ni, Co, Mn, and Li from SNCMB cathodes. Maximizing leaching rates for Ni (96.69 %), Co (95.38 %), Mn (97.64 %), and Li (98.72 %) under optimal conditions (80 ℃, 4 mol/L CA, 20 g/L solid to liquid (S/L) ratio, 2 vol% HP, 70 min). The Avrami equation models leaching kinetics, requiring a temperature of 80 ℃ to accelerate the process. Hydrogen-type strong acidic cation exchange resin (HR) effectively adsorbs Ni, Co, Mn, and Li ions from leachates through ion exchange under optimal conditions, reducing costs and eliminating the need for separating metals with similar chemical properties. This multi-stage adsorption recycling process renders leachates both economical and eco-friendly. The metal-enriched HR composite (HRC) from the ion-exchange process prepares ternary lithium battery (NCMB) cathodes to maximize metal usage. Microwave heating achieves excellent structure and electrochemical performance of regenerated ternary lithium battery (RNCM) cathodes, with 153.81 mAh/g discharge capacity at 0.1C rate and 90.92 % capacity retention after 50 cycles at 900 ℃ for 4 h. This innovative, efficient, and eco-friendly technique allows for closed-loop recycling of Ni, Co, Mn, and Li from SCNMB cathodes, providing new avenues for lithium battery recycling.

The Role of Zinc Triflate Additive for Improved Electrochemical Performance of Nickel-Rich Layered Oxide Lithium Battery Cathode via Suppression of Interfacial Parasitic Reactions

Nickel-rich layered oxide cathode materials with low cobalt content, such as LiNi0.90Mn0.05Co0.05O2 (NMC90), have the potential to enable cost-effective, high-energy-density lithium-metal batteries. However, NMC90 cathode materials are prone to severe parasitic reactions at higher voltages during prolonged cycling. The addition of small percentages of electrolyte additives to the neat commercial electrolyte can significantly enhance the overall electrochemical performance of lithium-metal batteries. This study investigates the effects of zinc triflate (Zn(Otf)2) as an electrolyte additive on the enhancement of the electrochemical performances of lithium-metal batteries comprising nickel-rich layered oxide cathode materials. X-ray photoelectron spectroscopy analysis revealed that Zn(Otf)2 decomposition leads to enhanced fluorination at the interfacial layers, which contributes to improved chemical stability. Utilizing operando electrochemical mass spectroscopy, we demonstrate that Zn(Otf)2 additives effectively suppress the electrolyte degradation, which is otherwise detrimental to electrochemical performance. Electrochemical studies show that the inclusion of only ∼1% Zn(Otf)2 as additive in neat commercial electrolyte enhances the electrochemical performance indicated by a 10% improvement in discharge capacity after 150 cycles. This study paves the way for researchers to develop novel fluorinated triflate based electrolyte additives aimed at enhancing the stabilization of interfaces for lithium ion, and potentially also Li-metal batteries.

A Study on the Microstructure Regulation Effect of Niobium Doping on LiNi0.88Co0.05Mn0.07O2 and the Electrochemical Performance of the Composite Material under High Voltage.

High-nickel ternary materials are currently the most promising lithium battery cathode materials due to their development and application potential. Nevertheless, these materials encounter challenges like cation mixing, lattice oxygen loss, interfacial reactions, and microcracks. These issues are exacerbated at high voltages, compromising their cyclic stability and safety. In this study, we successfully prepared Nb5+-doped high-nickel ternary cathode materials via a high-temperature solid-phase method. We investigated the impact of Nb5+ doping on the microstructure and electrochemical properties of LiNi0.88Co0.05Mn0.07O2 ternary cathode materials by varying the amount of Nb2O5 added. The experimental results suggest that Nb5+ doping does not alter the crystal structure but modifies the particle morphology, yielding radially distributed, elongated, rod-like structures. This morphology effectively mitigates the anisotropic volume changes during cycling, thereby bolstering the material's cyclic stability. The material exhibits a discharge capacity of 224.4 mAh g-1 at 0.1C and 200.3 mAh g-1 at 1C, within a voltage range of 2.7 V-4.5 V. Following 100 cycles at 1C, the capacity retention rate maintains a high level of 92.9%, highlighting the material's remarkable capacity retention and cyclic stability under high-voltage conditions. The enhancement of cyclic stability is primarily due to the synergistic effects caused by Nb5+ doping. Nb5+ modifies the particle morphology, thereby mitigating the formation of microcracks. The formation of high-energy Nb-O bonds prevents oxygen precipitation at high voltages, minimizes the irreversibility of the H2-H3 phase transition, and thereby enhances the stability of the composite material at high voltages.