Co_0.85Se Nanoparticles Encapsulated by Nitrogen-Enriched Hierarchically Porous Carbon for High-Performance Lithium-Ion Batteries

Coordination compound derivates (CCDs) have been widely applied in lithium-ion batteries (LIBs). However, the functionalization of CCDs with open structure and heteroatomic doping is still challenging. Herein, an effective functionalization strategy is presented to prepare a kind of CCD, where Co_0.85Se nanoparticles are encapsulated by nitrogen-enriched hierarchically porous carbon (CS/NPC) based on the heat treatment of a cobalt-complexed hexamethylolmelamine-polyvinylpyrrolidone resin (Co²⁺/HPR). The abundant free volume and enriched N species of the HPR are responsible for the hierarchically porous configuration and high N-doping of the composites. By controlling the content of cobalt salt and the heating rate, high specific surface area (440.7 m² g^-1), high N-doping (8.54 atom %), and suitable mass loading of Co_0.85Se (55.5%) were simultaneously achieved in CS-2/NPC-5, which delivers high reversible capacity (758.5 mAh g^-1 at 0.1 A g^-1), outstanding rate capability (401.7 mAh g^-1 at 5 A g^-1), and excellent cycling durability (638.4 mAh g^-1 at 1 A g^-1 after 200 cycles), suggesting a promising candidate for LIB anode materials.