Organic/Inorganic Hybrid Cross-Linked Gel Polymer Electrolyte for Optimizing the Solvation Structure of Lithium Ions

Lithium metal electrodes inevitably lead to the decomposition of the liquid electrolyte and lithium dendrite growth, both of which result in the formation of unstable solid electrolyte intermediates (SEIs). Gel polymer electrolytes (GPEs) are expected to replace liquid electrolytes for optimizing the SEI issues of lithium metal. Herein, a cellulose-based gel electrolyte cross-linked by thiol-modified polyhedral oligomeric silsesquioxane (thiol-modified-POSS) was successfully obtained based on “thiol–ene” click chemistry. This organic/inorganic hybrid cross-linked GPE not only exhibits high mechanical strength and structural stability but also promotes the generation of TFSI–-rich lithium-ion solvated structures, which in turn accelerates the generation of uniform and stable inorganic-rich SEIs. Relying on the stable SEIs between GPE and the lithium anode, the Li/GPE/LiFePO4 cell exhibits a capacity retention of 88% after 200 cycles at 0.5 C, which is much higher than GPEs without an inorganic cross-linker (only 33% capacity retention). We anticipate that this work will provide a good strategy to obtain high-performance organic/inorganic hybrid GPEs for lithium metal batteries.