Qian Lanting, Huang Yangyang, Dean Cameron, Kochetkov Ivan, Singh Baltej, Nazar Linda
Department of Chemistry and the Waterloo Institute of Nanotechnology, University of Waterloo, 200 University Ave, Waterloo ON, N2L 3G1, Canada.
Angew Chem Int Ed Engl. 2025 Jan 10;64(2):e202413591. doi: 10.1002/anie.202413591. Epub 2024 Dec 4.
Sulfide solid electrolytes such as LiPSCl hold high promise for solid-state batteries due to their high ionic conductivity; however, their oxidation potential of ~2.5 V is not compatible with high voltage Ni-rich cathodes such as LiNiCoMnO (x≥0.8). Using guidance from density functional theory, we devise an effective, conformal, and thin coating on the cathode active material, which suppresses the oxidative decomposition of LiPSCl as shown by experiment. The nanometric coating on nickel-rich NMC85 enabled capacity retention of 82 % after 200 cycles (2.8-4.3 V vs Li/Li) using LiPSCl as the solid electrolyte. In comparison, cells with an uncoated CAM only displayed 56 % capacity retention. The coated-NCM85 cells also demonstrate much better rate performance and higher capacity. The enhanced performance is due to the formation of a stable amorphous cathode-electrolyte interphase accruing from the decomposition products of the LiPOF precursor (as predicted by DFT), which protect the sulfide electrolyte from oxidation. The coating fabricated in this cost-effective process showed superior performance to state-of-the-art coatings such as LiNbO. This work highlights the importance of rationally designing stable coating materials based on their potential decomposition products and confirms the suitability of a low-cost and conformal coating to enable sulfide electrolyte-based all-solid-state batteries.
诸如LiPSCl之类的硫化物固体电解质因其高离子电导率而在固态电池方面具有很高的前景；然而，其约2.5 V的氧化电位与诸如LiNiCoMnO（x≥0.8）的高电压富镍阴极不兼容。利用密度泛函理论的指导，我们在阴极活性材料上设计了一种有效、保形且薄的涂层，实验表明该涂层可抑制LiPSCl的氧化分解。使用LiPSCl作为固体电解质，在富镍NMC85上的纳米涂层在200次循环（相对于Li/Li为2.8 - 4.3 V）后容量保持率为82%。相比之下，未涂覆阴极活性材料的电池容量保持率仅为56%。涂覆NCM85的电池还表现出更好的倍率性能和更高的容量。性能的提升归因于LiPOF前驱体分解产物形成了稳定的非晶态阴极 - 电解质界面（如DFT所预测），该界面保护硫化物电解质不被氧化。通过这种具有成本效益的工艺制备的涂层表现出优于诸如LiNbO等先进涂层的性能。这项工作突出了基于潜在分解产物合理设计稳定涂层材料的重要性，并证实了低成本保形涂层对于实现基于硫化物电解质的全固态电池的适用性。
