Lifan Wang,Pengfei Jiang,Yiheng Wu,Ruixiang Li,Min Chen,Xindong Wang,Chun Zhan,Guicheng Liu
The development of high-energy all-solid-state lithium-ion batteries (ASSLIBs) is hindered by interfacial incompatibility between Ni-rich layered oxides (LiNi 0.8 Co 0.1 Mn 0.1 O 2 , NCM811) and solid electrolytes (Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 , LATP), where co-sintering-induced Li + depletion and the subsequent oxygen release synergistically degrade electrochemical performance. Here, a dual-functional interface engineering strategy is developed through thermochemical coordination of dynamic lithium compensation and oxygen-anchoring modulation. Incorporation of 10 wt.% LiOH effectively suppresses cation interdiffusion during 700 °C co-sintering, while La 4 NiLiO 8 lithium–oxygen conductor stabilizes lattice oxygen via vacancy passivation, thus eventually protecting NCM811 from thermal decomposition (post-sintering XRD, XPS, and TEM). The optimized NCM811-LATP composite cathode achieves a high initial capacity of 217.1 mAh g −1 at 0.1 C with 80% capacity retention over 248 cycles a 143% lifespan improvement compared to baseline systems, while maintaining charge-transfer impedance below 97.8 Ω (EIS) and suppressing layered-to-spinel phase transitions (post-cycling TEM). This work establishes a universal paradigm for oxygen-interface co-stabilization in ASSLIBs, balancing thermochemical stability with interfacial ion transport to unlock ultra-stable cycling in high-energy-density solid-state systems.
Jingchi Zhang,Ze Hua,Ziqi Wu,Xinting Cao,Wen Yang,Ruiwen Shao,Yu Bai,Zhenhua Wang,Kening Sun
To satisfy the demands of modern society for high-energy–density sulfide-based all-solid-state lithium batteries (ASSLBs), Ni-rich cathode materials have gained much attention for their high capacity and energy density. However, their practical deployment is hindered by accelerated interface degradation and capacity decay originating from surface oxygen release and lattice oxygen activation during prolonged cycling. In this study, Ti x NbB (1− x ) C 2 was successfully coated on the surface of LiNi 0.94 Co 0.05 Mn 0.01 O 2 . Density functional theory (DFT) calculations first elucidate a “point-to-point” anchoring mechanism where each surface oxygen atom coordinates with single species (Ti/Nb/B) offered by Ti x NbB (1− x ) C 2 , which forms robust O–M bonds and sustain a stable interface structure. The electron energy loss spectroscopy (EELS) reveals the segregation of Ti/Nb toward subsurface layers during cycling, creating an optimized lattice oxygen coordination environment and suppressing oxygen activation. The dual oxygen stabilization mechanism dramatically improves the reversibility of phase transition and the structural stability of the Ni-rich cathode materials. Moreover, Ti x NbB (1− x ) C 2 as the protective layer decreases mechanical strain and suppresses the parasitic reactions. Consequently, the engineered cathode delivers 91% capacity retention after 1000 cycles at 0.3 C, suggesting excellent cycling stability. The research delivers a new design philosophy for the coating layer that can stabilize surface oxygen. Furthermore, the atomistic understanding of the structure–property relationship of the Ni-rich cathode materials provides valuable guidance for the future design of new cathode materials with superior structural stability in ASSLBs.
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