One-step synthesis of CoON@C with superior energy storage performance for lithium ion battery anode

Highlights: • A novel strategy for one-step synthesis of the CoON with uniform mixture of oxygen and nitrogen atoms is reported. • CoON is a promising anode material for LIBs. • The addition of nitrogen atoms can improve the performance of CoO in the aspect of stability and extrinsic pseudocapacitive. Cobalt oxynitride (CoON) is a promising material which combines the advantages of nitride and oxide. The application area of cobalt oxynitride is limited with the current preparation method, which can only obtain part of the cobalt oxynitride by nitriding the outermost surface of the oxide. In this research, a novel strategy of one-step synthesis of the CoON through solvothermal method is reported. The as-prepared CoON possesses uniformly mixed nitrogen and oxygen atoms, and exhibits an morphological structure of small particles agglomerating together simultaneously. Moreover, sodium citrate is added to prevent agglomeration by providing a matrix carbon in which CoON nanoparticles are randomly wrapped, rendering CoON more suitable for lithium-ion battery anode electrodes. A high reversible capacity of 1054 mAhg⁻¹ is achieved at a scan rate of 0.5 A g⁻¹ after 450 cycles. In addition, the application of CoON can be further extended to other areas by modifying the simple synthesis strategy.