Crosslinked electrospun poly(vinylidene difluoride) fiber mat as a matrix of gel polymer electrolyte for fast-charging lithium-ion battery

摘要

Gel polymer electrolyte (GPE), possessing a polymer matrix and embedded liquid electrolyte, is a critical component of lithium-ion batteries. To enhance GPE performance, in this work a self-crosslinkable poly(vinylidene difluoride) (PVdF) graft copolymer possessing Meldrum's acid (MA) groups as reactive sites has been prepared with atom transfer radical polymerization and utilized as a polymer matrix for GPEs. Compared to neat PVdF based GPEs, incorporation of MA groups to PVdF chains simultaneously brings crosslinking characteristic and high polarity to PVdF chains so as to enhance the thermal stability, mechanical strength, and polymer matrix-electrolyte affinity of the corresponding GPEs. The prepared GPE has an ionic conductivity of about 1.48 mS cm(-1), which is higher than the value of 0.98 mS cm(-1) measured on commercial Celgard 2325 (R) separator. Moreover, good Li-ion battery performance, including high discharge capacity (136 mAh g(-1) at 0.2 C) and high capacity retention at high C-rates (66% at 10 C and 50% at 15 C), has been recorded with the prepared GPE based LIBs, demonstrating the application potential of the developed GPE for fast-charging lithium-ion batteries. (C) 2017 Elsevier Ltd. All rights reserved.