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

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.