Fibrous gel polymer electrolyte for an ultrastable and highly safe flexible lithium-ion battery in a wide temperature range

Replacement of flammable liquid electrolytes with gel polymer electrolytes (GPEs) is a promising route to improve the safety of lithium-ion batteries (LIBs). However, polymer-based electrolytes have limited suitability at low/high temperatures due to the instability of the polymer at high temperatures and the low ionic conductivity of the gel state at low temperatures. Herein, an integrated design of electrodes/fibrous GPEs modified with graphene oxide (GO) is reported. Due to the integrated structure of electrodes/GPEs, the strong interface affinity between electrodes and GPEs ensures that the GPEs spun on electrodes do not shrink at high temperatures (160-180 degrees C), thus preventing a short circuit of electrodes. Moreover, after GO modification, oxygen-containing functional groups of GO can accelerate Li+ transport of GO-GPEs even at a low temperature of -15 degrees C. When these GPEs are applied to flexible LIBs, the LIBs show excellent electrochemical performance, with satisfactory cycling stability of 82.9% at 1 C after 1000 cycles at 25 degrees C. More importantly, at a high temperature of 160 degrees C, the LIBs can also discharge normally and light the green light-emitting diode. Furthermore, at a low temperature of -15 degrees C, 92.7% of its room-temperature capacity can be obtained due to the accelerated Li+ transport caused by GO modification, demonstrating the great potential of this electrolyte and integrated structure for practical gel polymer LIB applications.

Automated summary

This study presents an integrated design of electrodes/fibrous GPEs modified with graphene oxide (GO) to enhance the safety and performance of lithium-ion batteries.