Polymer electrolyte with dual functional groups designed via theoretical calculation for all-solid-state lithium batteries

Solid polymer electrolytes (SPEs) have great potential to solve the safety issue of lithium batteries, nevertheless, the design of SPE with well comprehensive performance has always been a formidable challenge. As we know, in the polymer different groups have different functions, and there are complex interactions between them. Hence, the roles of various functional groups in electrolytes is too complex to be clearly understood, which restricts the structural design of SPE by experience. Herein, theoretical calculations are conducted in designing polymer electrolyte with dual functional groups of ethylene carbonate (EC) and ethyoxyl (EO) group, revealing the interaction between lithium ions and different groups as well as the lithium ions migration mechanism. Designed SPE demonstrates high conductivity of 1.84 × 10⁻⁴ S cm⁻¹ (30 °C), and wide electrochemical window of 4.75 V. Combining with in-situ interface modification technology, the SPE not only prolongs solid-state LiFePO₄ (LFP)/Li battery cycle life to 600 cycles (110 mA h g⁻¹ retained), but also shows potential application in high energy density LiNi_0.5Co_0.2Mn_0.3O₂ (NCM523) cathode and Si anode batteries. In this work, theoretical calculation is demonstrated to be a high effective method for constructing the functional groups of polymer electrolyte matrix.