Nanosized CoSb Alloy Confined in Honeycomb Carbon Framework Toward High-Property Potassium-Ion and Sodium-Ion Batteries

Antimony-based materials are promising anode candidates for Na-/K-ion batteries (SIBs/PIBs) but limited by the mediocre cycle performance due to the large volume change. Herein, a honeycomb-like interconnected porous carbon framework embedded with CoSb nanoparticles is fabricated via a water-soluble template-assisted vacuum freeze-drying technology followed by a heat-treatment method. The CoSb nanocrystalline and 3D porous carbon matrix endow the CoSb@3DPCs composite electrode with a distinct structure, which buffers the volume expansion of Sb, shortens the diffusion distance of Na+/K+, and enhances the electronic conductivity. It exerts outstanding electrochemical properties in both SIBs and PIBs, such as remarkable cycling durability (the capacity is maintained at 211.2 mAh g(-1) after 500 cycles for SIBs and 287.5 mAh g(-1) for PIBs) and rate capability (144 mAh g(-1) at 5 A g(-1) for SIBs and 134 mAh g(-1) at 5 A g(-1) for PIBs). The kinetic analysis shows that up to 79% and 65% pseudocapacitance contributions for SIBs and PIBs are observed for CoSb@3DPCs at 4.0 mV s(-1). Herein, an ingenious design route and simple preparation method toward exploring the high-property electrode for PIBs and SIBs is provided, and broad application prospects in other electrochemical applications are opened up.