Solvation structure reorganization and interface regulation of poly (glycidyl POSS)-based electrolyte for quasi-solid-state lithium-ion batteries

The interfacial stability and some unexpected side reactions in quasi-solid-state lithium-ion batteries (LIBs) impede the practical application of the in-situ crosslinked polymer electrolytes. Herein, a novel in-situ crosslinked polymer electrolyte with eight-armed crosslinked supramolecular structure is constructed via cationic ring-opening polymerization of glycidyl polyhedral oligomeric silsesquioxane (POSS). The strong electrostatic and hydrogen bonding interactions of the POSS blocks with anions reorganize the solvation structure, and the overall oxidation resistance of anions can be also effectively enhanced benefiting from the relatively electron-withdrawing effect of the POSS blocks. Simultaneously, a hierarchical cathode-electrolyte interphase with flexibility and oxidation resistance is constructed involving the boron difluoride radical-catalyzed cleavage of Si-O-Si linkages in POSS frameworks. The poly (glycidyl POSS)-based electrolyte enables the Li||NCM83 cell to possess a high capacity retention of 79.1 % after 500 cycles. Moreover, the SiO_x||NCM83 battery shows a capacity retention of 87.6 % after 200 cycles. These insights gained form this work opens up an avenue for the development and practical application of quasi-solid-state LIBs.