Porous poly(vinylidene fluoride) (PVDF) membrane with 2D vermiculite nanosheets modification for non-aqueous redox flow batteries

Lack of high-performance membrane seriously limits the performance of non-aqueous redox flow batteries (NARFBs). Here, a porous poly(vinylidene fluoride) (PVDF) membrane with 2D vermiculite nanosheets modification is proposed and prepared. The vermiculite nanosheets act as barriers to alleviate the crossover of active species. The hydrogen bonding between vermiculite and PVDF skeleton effectively mitigates the swelling rate and increases the mechanical strength of the membrane. The resultant battery constructed with the new porous membrane exhibits higher Coulombic efficiency (97.9% vs 84.6%) and large average discharge capacity (0.132 vs 0.088 Ah L⁻¹) compared with the one with pristine PVDF membrane at 2 mA cm⁻². The vermiculite nanosheets have little effect on the voltage efficiency (90.6% vs 92.7%).