Nitrogen-doped porous carbon spheres anchored with Co₃O₄ nanoparticles as high-performance anode materials for lithium-ion batteries

In this work, Co₃O₄ nanoparticles were loaded on the nitrogen-doped porous carbon spheres (NPCS) by a facile hydrothermal method. The NPCS were derived from carboxymethyl chitosan as the carbon and nitrogen source. The as-prepared Co₃O₄/NPCS nanocomposites were used as anode materials for lithium-ion batteries. The electrochemical results showed that the materials possessed a high initial discharge capacity of 1245.5 mAh g^-1 and still maintained a high reversible capacity of 983.9 mAh g^-1 after 100 cycles at a current density of 100 mA g^-1. Even at a high current density of 5 A g^-1, it delivered a very stable reversible capacity of 659 mAh g^-1. The high electrochemical performance of the Co₃O₄/NPCS nanocomposites can be attributed to the synergistic effects of the nanoscale Co₃O₄ particles, the porous structure of the NPCS and the N functional groups on the NPCS.