Microporous bayberry-like nano-silica fillers enabling superior performance gel polymer electrolyte for lithium metal batteries

Abstract

Unlike conventional organic liquid electrolytes, which have uncontrollable lithium dendrite growth and serious safety concerns, gel polymer electrolytes (GPEs) are widely considered to be one of the best candidates for the next generation of high energy density lithium metal batteries (LMBs). However, the challenge of maintaining high mechanical strength and good electrochemical stability simultaneously has not yet been met by these materials. Therefore, in this paper, we designed bayberry silica nanoparticles (BSNPs) with ultra-high specific surface area and compounded them with polyvinylidene fluoride – hexafluoropropylene (PVDF-HFP) (BSNPs-CPE) to effectively solve these problems. The results show that compared with the blank sample and industrial silica nanoparticles (SNPs-CPE) composite electrolyte, BSNPs-CPE not only has higher absorption rate and ion conductivity but also has a higher lithium-ion migration. In addition, due to the good compatibility between BSNPs-CPE and lithium metal, a stable SEI layer can be generated. At the same time, lithium metal batteries of BSNPs-CPE exhibit good cycling performance and rate capacity. After 300 cycles, the excellent capacity of up to 147.2 mAh g− 1 remains at the current rate of 1.0 C. More encouragingly, the capacity of 119 mAh g− 1 was obtained at the current rate of 10 C, which keeps much higher than that of the blank sample (76.2 mAh g− 1). This kind of nanostructure with micropore and high specific surface area provides important significance for the design of high-performance lithium metal battery.