A flexible Cellulose/Methylcellulose gel polymer electrolyte endowing superior Li+ conducting property for lithium ion battery

摘要

With the advent of gel polymer electrolyte (GPE), a series of safety problems of lithium ion batteries have been resolved. However, poor self-standing property, the low ionic conductivity and Li+ transference number are still the obstacles that impede the practical application of GPE. Herein, a flexible and eco-friendly GPE is designed using allyl-modified cellulose with methylcellulose through simple UV curing. The crosslinked structure facil-itates the integrity of GPE during use, and methylcellulose guarantees the high affinity to liquid electrolyte and improve interfacial compatibility. The specific polar functional groups (-OH,-OCH3 and-C-O-C-) in GPE cooperate to enhance the lithium salt dissociation, anion immobilization and lithium ion transporting and enable the high Li+ transference number (0.902) and ion conductivity (4.36 x 10(-3) S cm(-1)). The assembled Li/GPE/ LiFePO4 coin cells possess high initial discharge capacity of 150.6 mA h g(-1) and a high capacity retention of 91.6 % after 100 cycles.