Hypercrosslinked Metal‐Organic Polyhedra Electrolyte with High Transference Number and Fast Conduction of Li Ions

Solid‐state electrolytes (SSEs) with high Li‐ion transference numbers and fast ionic conductivity are urgently needed for technological innovations in lithium‐metal batteries. To promote the dissociation of ion pairs and overcome the mechanical brittleness and interface defects caused by traditional fillers in polymeric electrolytes, we designed and fabricated a cationic hypercrosslinking metal‐organic polyhedra (HCMOPs) polymer as SSE. Benefiting a three‐component synergistic effect: cationic MOPs, branched polyethyleneimine macromonomer and polyelectrolyte units, the Li‐HCMOP electrolyte possesses a high Li‐ion conductivity, a high Li‐ion transference number and a low activation energy. Their LiFePO4/Li batteries exhibit high capacity with superior rate performance and cycling stability. Moreover, soluble MOPs serve as high crosslinking nodes to provide excellent mechanical strength for electrolytes and good compatibility with polymers. This work highlights an effective idea of high‐performance MOP‐based solid‐state electrolytes applied in LMBs.