Porous polyhedral carbon matrix for high-performance Li/Na/K-ion battery anodes

A carbon matrix for high-capacity Li/Na/K-alloy-based anode materials is required because it can effectively accommodate the variation in the volume of Li/Na/K-alloy-based anode materials during cycling. Herein, a nanostructured porous polyhedral carbon (PPC) was synthesized via a simple two-step method consisting of carbonization and selective acid etching, and their electrochemical Li/Na/K-ion storage performance was investigated. The highly uniform PPC, with an average particle size of 800 nm, possesses a porous structure and large specific surface area of 258.82 cm² g^–1. As anodes for Li/Na/K-ion batteries (LIBs/NIBs/KIBs), the PPC matrix exhibited large initial reversible capacity, fast rate capability (LIB: ~ 320 mAh g^–1 at 3C; NIB: ~ 140 mAh g^–1 at 2C; KIB: ~ 110 mAh g^–1 at 2C), better cyclic performance (LIB: ~ 550 mAh g^–1; NIB: ~ 210 mAh g^–1; KIB: ~ 190 mAh g^–1 at 0.2C over 100 cycles), high ionic diffusivity, and excellent structural robustness upon cycling, which demonstrates that the PPC matrix can be highly used as a carbon matrix for high-capacity alloy-based anode materials for LIBs/NIBs/KIBs. Graphical abstract: [Figure not available: see fulltext.]