Quantitative image-analysis framework for precise discrimination of cation mixing in high-nickel NCM cathodes

NCM‐based lithium layered oxides (LiNi1–x–yCoxMnyO2) have become prevalent cathode materials in state‐of‐the‐art lithium‐ion batteries. Higher energy densities can be achieved in these materials by systematically increasing the nickel content; however, this approach commonly results in inferior cycle stability. The poor cycle retention of high‐nickel NCM cathodes is generally attributed to chemo‐mechanical degradation (e.g., intergranular microcracks), vulnerability to oxygen‐gas evolution, and the accompanying rocksalt phase formation via cation mixing. Herein, the feasibility of doping strategies is examined to mitigate these issues and effective dopants for high‐nickel NCM cathodes are theoretically identified through a stepwise pruning process based on density functional theory calculations. Specifically, a sequential three‐step screening process is conducted for 38 potential dopants to scrutinize their effectiveness in mitigating chemo‐mechanical lattice stress, oxygen evolution, and cation mixing at charged states. Using this process, promising dopant species are selected rationally and a silicon‐doped LiNi0.92Co0.04Mn0.04O2 cathode is synthesized, which exhibits suppressed lattice expansion/contraction, fewer intergranular microcracks, and reduced rocksalt formation on the surface compared with its undoped counterpart, leading to superior electrochemical performance. Moreover, a comprehensive map of dopants regarding their potential applicability is presented, providing rational guidance for an effective doping strategy for high‐nickel NCM cathodes.

LiNi0.8Co0.1Mn0.1O2 (NCM811), a high‐nickel layered oxide, has emerged as a frontrunner for next‐generation lithium‐ion batteries (LIBs) due to its high energy density, excellent rate performance, and cost‐effectiveness. However, NCM811 cathodes face multifaceted challenges, including cation mixing, microcracking, and residual lithium compounds, necessitating a comprehensive understanding for addressing these critical issues. In this review, we provide an in‐depth analysis of recent advancements, presenting actionable insights into effective strategies to address the key issues in the NCM811 cathode and proposing pathways for optimizing NCM811 cathodes in LIB applications. Additionally, the forward‐looking perspectives are explored in this review, highlighting the role of advanced material characterization techniques, theoretical modeling, and computational simulations in overcoming the inherent limitations of NCM811 cathodes. By synthesizing current knowledge and technological advancements, this review aims to serve as a foundational resource for researchers and industry professionals striving to enhance the performance and accelerate the commercialization of NCM811 cathode materials, contributing to the future of energy storage solutions.

Understanding fundamental effects of Cu impurity in different forms for recovered LiNi0.6Co0.2Mn0.2O2 cathode materials

The exponential growth of lithium-ion batteries (LIBs) in electric vehicles and energy storage systems has amplified the urgent need for sustainable recycling strategies. Conventional pyrometallurgical and hydrometallurgical methods for LIB recycling are energy-intensive, chemically demanding, and fail to preserve the structural integrity of cath-ode materials. Closed-loop recycling, in contrast, enables the recovery of layered oxides with minimal processing steps, reducing environmental footprint and supporting a circular economy. This study provides a systematic comparison of two regeneration approaches—sol–gel synthesis and hydroxide co-precipitation—for closed-loop recycling of layered NCM (LiNixCoyMnzO2) cathode materials recovered from spent LIBs. Spent cells were mechani-cally processed and leached using malic acid to recover Ni, Co, Mn, which were subsequently used to synthesize NCM622 cathode powders. The regenerated materials were characterized using SEM/EDX, XRD, and electrochemical testing in CR2032 coin cells. Both methods successfully produced phase-pure layered oxides with the R-3m structure, with distinct differences in structural ordering and electrochemical behavior. The sol–gel-derived NCM622 displayed higher crystallinity and reduced cation mixing, evidenced by an I(003)/I(104) ratio of 1.896 compared to 1.720 for the co-precipitated sample, and delivered a high initial discharge capacity of 170 mAh/g at 0.1 C. However, it exhibited significant capacity fade, retaining only 60 mAh/g after 40 cycles. In contrast, the co-precipitation route produced hierarchical porous spherical agglomerates that offered superior cycling stability, maintaining ~150 mAh/g after 40 cycles with lower polarization (ΔEp = 0.16 V). Both materials demonstrated electrochemical performance comparable to commercial NCM. Overall, hydroxide co-precipitation emerged as the most industrially viable method due to scalable processing, compositional robustness, and improved long-term stability of regenerated cathodes. This work highlights the critical influence of synthesis route selection in LIB closed-loop recycling and provides a technological framework for industrial recovery of high-value NCM cathode materials.

Boosting cycle stability of NCM811 cathode material via 2D Mg-Al-LDO nanosheet coating for lithium-ion battery

Ni-rich LiNixCoyM1-x-yO2 (NCM; M=Mn, Al) cathode materials for lithium-ion batteries: Challenges, mitigation strategies, and perspectives

The development of cathode materials with good electrochemical performance is vital to the effort to design rechargeable batteries for applications such as electric mobility. Li-intercalated mixed transition-metal layered oxides such as LiNixCoyMn(1–x–y)O2 (NCM) and LiNixCoyAl(1–x–y)O2 (NCA) have gained considerable attention due to their good electrochemical properties. The properties of these materials are strongly affected by the arrangement of ions in their crystal lattice, yet accurate determination of this arrangement using experiments and theory remains a challenge. Here, we present a hybrid approach based on Monte Carlo (MC) and simulated annealing (SA) in conjunction with an empirical potential to determine the most probable ionic arrangements from a large number of possibilities. The MCSA approach is followed by a density functional theory (DFT)-based rescoring to determine the energetically most favorable configurations at a higher level of theory. The MCSA + DFT approach is tested on several well-known NCM and NCA cathode materials. We also employed this approach to determine the energetically favored dopant sites and cation mixing configurations. The lowest-energy configurations are then validated by comparing calculated structural parameters, electronic structures and 7Li NMR chemical shifts with experiments. The MCSA + DFT approach reported here is a computationally cheap and efficient approach for structure prediction of mixed transition-metal-based materials.