Heteroatom-doped carbon materials with interconnected channels as ultrastable anodes for lithium/sodium ion batteries

Carbon materials have been extensively investigated as promising negative electrode materials for lithium/sodium ion batteries. However, most common carbon materials always suffer from limitations in regards to high reversible capacity and long-term cycling stability because of their low theoretical specific capacities and sluggish kinetics. Herein, we report a facile MOF-derived strategy for the synthesis of nitrogen/oxygen co-doped porous carbon polyhedra (NOPCP) with abundant channel-connected cavities with their inner surface decorated with a large number of N and O atoms, which can provide a large number of active sites (defects and edge doping sites) for the sorption of Li⁺/Na⁺. These cavities can also be considered as "ponds" where the electrolyte is stored, which shortens the diffusion distance of ions during the discharge/charge process. When evaluated as an anode material for LIBs, NOPCP-600 delivers a high reversible capacity of 1663 mA h g^-1 at 0.1 A g^-1 after 120 cycles and superior cycling stability with a capacity of 667 mA h g^-1 after 1000 cycles at 2 A g^-1. For SIBs, NOPCP-600 delivers a high reversible capacity of 313 mA h g^-1 at 0.1 A g^-1 after 100 cycles and an excellent long-term cycling stability of 228 mA h g^-1 at 1 A g^-1 after 2000 cycles.