3D ultraviolet polymerized electrolyte based on PEO modified PVDF-HFP electrospun membrane for high-performance lithium-sulfur batteries

At present, the quasi-solid-state lithium-sulfur batteries (LSBs) assembled with sulfur cathode, gel polymer electrolyte (GPE) and Li anode have explored a novel prospect for substantial energy applications owing to the high energy density and elevated security. In this work, we propose a 3D ultraviolet polymerized electrolyte, in which the inner substrate is the PEO modified PVDF-HFP electrospun membrane, and the hydrogen bonding effect plays a critical role in regulating the nanofiber diameter and membrane porosity. Simultaneously, outside coating is the in-situ ultraviolet polymerized pentaerythritol tetrakis-divinyl adipate (PETT-DA) layer, in which the carbonyl groups can effectively suppress the polysulfides shuttling. Consequently, the optimal electrolyte membranes with high porosity possess the high electrolyte uptake of 279.8%, ionic conductivity of 9.64 × 10−4 S cm−1 and Li+ transference number of 0.71 at 25 °C. Prominently, the assembled quasi-solid-state LSBs exhibit the stable coulombic efficiency of 99.5–100.0% over 300 cycles and good capacity retention of 87.1% after 300 cycles at 2C. More importantly, excellent thermal dimensional properties and mechanical performances further provide great commercial potentials for our synthesized 3D electrolyte membranes. [Display omitted] •Substrate and outside coating have good connection and engender synergistic effect.•Inner electrospun nanofiber substrate guarantees the high electrolyte uptake.•Theoretically, hydrogen bonds between PEO and PVDF-HFP play a critical role in controlling the diameter of the nanofibers.•Ultraviolet polymerized coating layer confines shuttle effect due to carbonyl groups.