Effect of various electrophoretically deposited nano‐silica contents on the properties of poly(vinylidene fluoride‐co‐hexafluoropropylene)‐based electrospun polymer electrolytes

Abstract

Poly(vinylidene fluoride-co-hexafluoropropylene) (P(VDF-HFP)) based composite polymer electrolyte (CPE) membranes were successfully prepared by electrospinning followed by electrophoretic deposition processes, and desirable polymer electrolytes were obtained after being activated in liquid electrolytes. The physicochemical properties of the CPEs with different electrophoretically deposited nano-SiO 2 contents were investigated by SEM, XRD, TGA, linear sweep voltammetry and electrochemical impedance spectroscopy measurements. When the ratio of electrophoretically deposited nano-SiO 2 to P(VDF-HFP) is up to 4 wt%, the results show that the CPE membrane presents a very uniform surface with abundant interconnected micropores and possesses excellent mechanical tensile strength with high thermal and electrochemical stability; the ionic conductivity at room temperature can reach 3.361 mS cm −1 and the reciprocal temperature dependence of the ionic conductivity follows a Vogel − Tamman − Fulcher relationship. The interfacial resistance of the assembled Li/CPE/Li simulated cell can rapidly increase to a steady value of about 950 from the initial value of about 700 at 30 ∘ C during 15 days' storage. The battery performance test suggests that the CPE also shows excellent compatible properties with commercial LiCoO 2 and graphite materials.

Research progress in stable interfacial constructions between composite polymer electrolytes and electrodes

“…Therefore, it is important to reduce the effective current density and improve the mechanical strength of the electrolyte to inhibit the growth of dendrites and achieve a long cycle life for PSSBs. 124 On the one hand, from the perspective of the electrolyte, designing CPEs with different fillers to accomplish high mechanical strength is very necessary. This is because filler-filled CPEs with 3D structures and high mechanical strength can induce uniform deposition of Li + and slow down the growth rate of Li dendrites.…”