Molten salt synthesis of KCl-preintercalated C3N4 nanosheets with abundant pyridinic-N as a superior anode with 10 K cycles in lithium ion battery.

The graphitic carbon nitride is considered as the promising anode of lithium ion battery due to its high theoretical capacity (>1000 mAh g-1) and easy synthesis method. But the electrochemical inactivity and the structural collapse during cycles lead to its poor electrochemical performance in practice. Here, an interesting molten salt method is used to obtain the KCl-preintercalated carbon nitride nanosheets with abundant N vacancies and pyridinic-N. The KCl as a prop enhances the interlayer distance and the structural stability. And the N vacancy and the pyridinic-N increase the conductivity, the active sites and the reversibility of Li+ storage. Thus, the optimized electrode shows a higher specific discharge capacity (389 mAh g-1 at 0.1 A g-1) and a longer cyclic life (66% capacity retention after 10 K cycles at 3.0 A g-1) compared to those of bulk g-C3N4.