Lu Guozhong, Jiang Ying, Wu Xiang, Geng Fushan, Li Chao, Hu Bingwen, Shen Ming
Shanghai Key Laboratory of Magnetic Resonance, School of Physics and Electronic Science, East China Normal University, Shanghai, 200241, P. R. China.
ChemSusChem. 2023 Oct 20;16(20):e202300517. doi: 10.1002/cssc.202300517. Epub 2023 Aug 7.
Interfacial side reactions and space charge layers between the oxide cathode material and the sulfide solid-state electrolytes (SSEs), along with the structural degradation of the active material, significantly compromise the electrochemical performance of all-solid-state batteries (ASSLBs). Surface coating and bulk doping of the cathodes are considered the most effective approaches to mitigate the interface issues between the cathode and SSEs and enhance the structural integrity of composite cathodes. Here, a one-step low-cost means is ingeniously designed to modify LiCoO (LCO) with heterogeneous Li TiO /Li(TiMg) O surface coating and bulk gradient Mg doping. When applied in Li GeP S -based ASSLBs, the Li TiO and Li(TiMg) O coating layers effectively suppress interfacial side reactions and weaken space charge layer effect. Furthermore, gradient Mg doping stabilizes the bulk structure to mitigate the formation of spinel-like phases during local overcharging caused by solid-solid contact. The modified LCO cathodes exhibit excellent cycle performance with a capacity retention of 80 % after 870 cycles. This dual-functional strategy provides the possibility for large-scale commercial implementation of cathodes modification in sulfide based ASSLBs in the future.
氧化物阴极材料与硫化物固态电解质（SSE）之间的界面副反应和空间电荷层，以及活性材料的结构退化，严重损害了全固态电池（ASSLB）的电化学性能。阴极的表面涂层和体相掺杂被认为是缓解阴极与SSE之间界面问题以及增强复合阴极结构完整性的最有效方法。在此，巧妙地设计了一种一步低成本方法，通过异质LiTiO/Li(TiMg)O表面涂层和体相梯度Mg掺杂来修饰LiCoO（LCO）。当应用于基于LiGePS的ASSLB时，LiTiO和Li(TiMg)O涂层有效地抑制了界面副反应并减弱了空间电荷层效应。此外，梯度Mg掺杂稳定了体相结构，以减轻在固-固接触导致的局部过充电过程中尖晶石状相的形成。改性的LCO阴极表现出优异的循环性能，在870次循环后容量保持率为80%。这种双功能策略为未来基于硫化物的ASSLB中阴极改性的大规模商业应用提供了可能性。
