Rapid ion conduction enabled by synergism of oriented liquid crystals and Electron-Deficient boron atoms in multiblock copolymer electrolyte for advanced Solid-State Lithium-Ion battery

Liquid crystals (LCs) with characteristics of self-orientation have exhibited superiorities in construction of ordered ion channels for rapid Li-ion transport. Herein, reversible addition-fragmentation chain transfer (RAFT) polymerization is employed to synthesize a unique type of boron-containing LCs based ABCBA type multiblock copolymers for the first time. The composite block copolymer electrolytes (BCPEs) are fabricated by introducing the copolymer electrolytes into glass fiber separator via solution-casting method. Noteworthily, LCs can not only provide ordered ion channels for efficient ion conduction, but also ameliorate the mechanical strength. Meanwhile, the nitrile groups with high polarity from LCs are able to further facilitate lithium salt dissociation and reinforce electrochemical stability of the system. Crucially, boron elements with electron deficiency can anchor anions and adsorb impurities to endow BCPEs with boosted ion transport capability and sufficient electrochemical stability. Consequently, the well-designed electrolyte shows high ionic conductivity of 1.13 x 10-4 S cm-1 (30 degrees C), and broadened electrochemical stability window of 4.85 V. Impressively, the assembled Li/ LiFePO4 cells and even Li/LiMnxFe1-xPO4 high-voltage cells exhibit remarkable performances. This work provides a synthetic strategy of structure-controlled polymer electrolyte matrix and illustrates that the BCPEs are definitely a category of satisfactory electrolyte candidate for high-performance solid-state lithium-ion batteries.