用不易燃固体电解质(SE)代替锂电池中的易燃有机液体电解质对于提高各种应用的安全性至关重要。包括便携式电子产品,电动汽车,和可扩展的能源存储。由于典型的阴极材料不具有超离子导电性,阴极中的锂离子传导主要依赖于引入大量SE作为添加剂以形成复合阴极。这大大损害了固态锂电池的能量密度。这里,我们演示了卤化物SE,Li3VCl6不仅表现出良好的Li+导电性,但更重要的是,提供约80mAhg-1的高度可逆容量,与Li+/Li相比,平均电压为3V。Li3VCl6的离子电导率在电化学锂化/脱锂时经历了边际波动,因为其典型的固溶体反应仅导致锂空位的减少。当与传统的LiFePO4阴极结合时,活性Li3VCl6阴极电解液可实现令人印象深刻的217.1mAhg-1LFP容量,与非活性阴极电解液相比,能量密度增加约50%。利用可用作活性材料的阴极电解液的整体质量提供了提高额外容量的机会,使其在应用中可行。本文受版权保护。保留所有权利。
Replacing flammable organic liquid electrolytes with nonflammable solid electrolytes (SEs) in lithium batteries is crucial for enhancing safety across various applications, including portable electronics, electric vehicles, and scalable energy storage. Since typical cathode materials do not possess superionic conductivity, Li-ion conduction in the cathode predominantly relies on incorporating a significant number of SEs as additives to form a composite cathode, which substantially compromises the energy density of solid-state lithium batteries. Here, a halide SE, Li3VCl6 is demonstrated, which not only exhibits a decent Li+ conductivity, but more importantly, delivers a highly reversible capacity of approximately 80 mAh g-1 with an average voltage of 3 V versus Li+/Li. The ionic conductivity of Li3VCl6 experiences marginal fluctuations upon electrochemical lithiation/delithiation, as its prototypical solid-solution reaction results solely in a reduction of lithium vacancy. When combined with the traditional LiFePO4 cathode, the active Li3VCl6 catholyte enables an impressive capacity of 217.1 mAh g-1 LFP and about 50% increase in energy density compared with inactive catholytes. Harnessing the integrated mass of the catholyte-which can serve as an active material-presents an opportunity to boost the extra capacity, rendering it feasible in applications.