Carbon Nitride Nanofibres with Exceptional Lithium Storage Capacity: From Theoretical Prediction to Experimental Implementation

Abstract Graphitic carbon nitride nanosheet (i.e., g‐C 3 N 4 ) is identified as a suitable graphene analogue due to its high theoretical capacity, wider and vacant structure, and easy synthesis method. Currently, g‐C 3 N 4 nanosheet has limited application in lithium‐ion batteries (LIBs) which is mainly due to the lack of effective intercalation/deintercalation reaction sites, the high binding energy of the Li to the nanosheet, and insufficient conductivity and stability. Density functional theory calculation predicts that the edges of g‐C 3 N 4 fibre have a suitable adsorption energy and bestow a balanced adsorption force and desorption freedom to Li. In order to verify this prediction, g‐C 3 N 4 nanofibre is synthesized with the edges and pores, as well as higher pyridinic nitrogen content, using a simple polymerization/polycondensation method. The as‐prepared g‐C 3 N 4 fibre delivers a remarkable specific capacity of 181.7 mAh g −1 , as well as extraordinary stability and power density. At a high rate of 10C, the g‐C 3 N 4 fibre still has a specific capacity of 138.6 mAh g −1 even after 5000 cycles, being the best‐performing g‐C 3 N 4 electrode so far in literature. This work is exemplary in combining theoretical computing and experimental techniques in designing the next generation of electroactive materials for LIBs.