A single-ion conductive composite gel electrolyte based on helical mesoporous silica nanofibers for high-performance...

Gel polymer electrolytes (GPEs) combined with organic liquid plasticizer, lithium salt and solid-state polymer are expected to achieve the fusion of high safety, high ionic conductivity and good electrode-electrolyte interface compatibility. Meanwhile, single-ion conductive electrolyte with high lithium-ion transference number (t_Li+) can effectively prevent the formation of lithium dendrites and improve the power density of the battery. Therefore, it's meaningful to develop single-ion conductive GPEs to improve the comprehensive property of lithium-ion batteries (LIBs). In this paper, a single-ion conductive composite gel electrolyte (SCGE) was designed and synthesized. Helical mesoporous silica@polydopamine-graft-lithium salt (SPL) nanofibers were dispersed in poly(vinylidene fluoride-hexafluoropropylene) matrix to form a porous SCGE membrane with considerable liquid electrolyte uptake (605 %). The organic/inorganic hybrid SPL anchors the anions of lithium salts, promotes the dissociation of Li⁺ and helps its rapid conduction, achieving high t_Li+ (0.94). When the SPL content in the SCGE membrane is 30 wt% (denoted as S3-CGE), the assembled Li|S3-CGE|Li battery only generates an overpotential of 0.1 V after cycling for 1000 h at the current density of 0.1 mA cm^-2. The assembled LFP|S3-CGE|Li battery has a first-cycle specific capacity of 150.1 mAh g^-1 at 0.1C and can cycle stably at different current densities. These results show that the SCGE has great potential for practical application in high performance LIBs.