Build a High‐Performance All‐Solid‐State Lithium Battery through Introducing Competitive Coordination Induction Effect in Polymer‐Based Electrolyte

Abstract

Polymer‐inorganic composite electrolytes (PICE) have attracted tremendous attention in all‐solid‐state lithium batteries (ASSLBs) due to facile processability. However, the poor Li+ conductivity at room temperature (RT) and interfacial instability severely hamper the practical application. Herein, we propose a concept of competitive coordination induction effects (CCIE) and reveal the essential correlation between the local coordination structure and the interfacial chemistry in PEO‐based PICE. CCIE introduction greatly enhances the ionic conductivity and electrochemical performances of ASSLBs at 30°C. Owing to the competitive coordination (Cs+…TFSI−…Li+, Cs+…C‐O‐C…Li+ and 2,4,6‐TFA…Li…TFSI−) from the competitive cation (Cs+ from CsPF6) and molecule (2,4,6‐TFA: 2,4,6‐trifluoroaniline), a multimodal weak coordination environment of Li+ is constructed enabling a high efficient Li+ migration at 30oC (Li+ conductivity: 6.25×10−4 S cm−1; tLi+ = 0.61). Since Cs+ tends to be enriched at the interface, TFSI− and PF6−in‐situ form LiF‐Li3N‐Li2O‐Li2S enriched solid electrolyte interface with electrostatic shielding effects. The assembled ASSLBs without adding interfacial wetting agent exhibit outstanding rate capability (LiFePO4: 147.44mAh g−1@1C and 107.41mAhg−1@2C) and cycling stability at 30oC (LiFePO4:94.65%@200cycles@0.5C; LiNi0.5Co0.2Mn0.3O2: 94.31%@200cycles@0.3C). This work proposes a concept of CCIE and reveals its mechanism in designing PICE with high ionic conductivity as well as high interfacial compatibility at near RT for high‐performance ASSLBs.