g-C3N4 nanosheets enhanced solid polymer electrolytes with excellent electrochemical performance, mechanical properties, and thermal stability

Abstract

Solid polymer electrolytes (SPEs) are expected to improve the safety and performance of lithium ion batteries (LIB). However, the low ionic conductivity limit the further application of PEO based electrolytes. Herein, g-C₃N₄ nanosheets is proposed as a novel filler for PEO based electrolytes. The addition of g-C₃N₄ improves the electrical properties (ionic conductivity, lithium ion transference number and electrochemical window), mechanical properties and thermal stability of the composite electrolyte. The two-dimensional g-C₃N₄ forms an effective ion transport network in the composite electrolyte. In addition, the surface atoms of the g-C₃N₄ interact with groups in the lithium salt, promoting further dissociation of the lithium salt. Furthermore, the all solid state batteries assembled by the g-C₃N₄ composite electrolyte exhibited good cycle performance at 60 °C (remained at 155 mA h g⁻¹ after 100 cycles). Owing to the simple synthesis and environmental friendliness, g-C₃N₄ nanosheets has a certain practical prospect as a filler for solid polymer electrolytes.