Recent progress of poly (vinylidene fluoride) based solid-state ionogel electrolytes in improving electrochemical performance.

Ionic liquids (ILs)-incorporated solid-state polymer electrolytes (iono-SPEs) have high ionic conductivities and can address the safety issues caused by the flammable liquid electrolytes. However, when assembled into lithium metal batteries (LMBs), most iono-SPEs displayed limited cycling durations due to the much poorer lithium ions (Li) transportation in polymer phase than in IL phase and polymer-IL interphase. Therefore, it is of great significance to reduce the phase-dependent differences in Li transport. Poly(vinylidene fluoride) (PVDF) and its based co-/ter- polymers with good electrochemical stability and high mechanical strength show great promise to improve the ionic conductivity of the polymer phase of iono-SPEs. However, there is no review to summarize the recent progress of PVDF based iono-SPEs in improving their electrochemical performance. In this review, we summarize the modifications on PVDF based iono-SPEs in terms of four aspects, namely, PVDF matrix modification, introduction of fillers, ILs modification, and interface modififaction. In particular, a recent work conducted by our group by employing a unique poly(vinylidene fluoride-trifluoroethylene-chlorotrifluoroethylene) [P(VDF-TrFE-CTFE)] as the matrix of ILs to uniform the Li transportation in different phases of iono-SPEs is reviewed in detail. Moreover, future developments of high-performance PVDF-based iono-SPEs are outlooked. This review can bring effective insights into the future development of iono-SPEs.