Abstract
Poly(vinylidene fluoride) (PVDF)-based polymer electrolytes have attracted widespread attention due to their unique Li(+) transport mechanism. However, their low ionic conductivity and porous structure, as well as residual solvent limit their application at high current densities. Here, a composite solid electrolyte (CSE) is developed by integrating poly(vinylidene-co-trifluoroethylene) [P(VDF-TrFE)] in its all-trans conformation with aminofunctionalized metal-organic framework (ZIF-90-NH(2)). In such a CSE, all F atoms located on one side of the polymer chain, providing fast Li(+) transport channels. Concurrently, the functionalized ZIF-90-NH(2) can effectively anchor the residual N, N-dimethylformamide (DMF) in CSEs while weakening Li(+)-DMF solvent coordination, inducing the rearrangement of Li(+) solvation structure and inhibiting the decomposition of DMF at the interface. Synergistically, ZIF-90-NH(2) can immobilize anions in Li salts, promoting their dissociation. Based on integrating competitive Li(+) coordination with immobilized anions, the obtained CSEs exhibit a high Li(+) transference number (0.77). The full cells with LiFePO(4) cathode can run stably over 400 cycles at 5 C, while the Li || LiNi(0.7)Co(0.1)Mn(0.2)O(2) full cells deliver a high capacity retention (>85%) after 200 cycles at a charge cutoff voltage of 4.5 V. This work opens up a new path for building CSEs with high interfacial stability and fast Li(+) transport.