Delocalized C⁼S decorates a 3D sp²-hybridized carbon skeleton for superior charge transfer kinetics of anodes

Efficient three-dimensional (3D) spatial charge transfer in carbon anodes is crucial for improving the storage kinetics of alkali metal ion batteries. To achieve this, regulating the sp(2)-hybrid carbon skeleton within 3D penetration networks is an innovative approach. In this study, delocalized (CS)-S-= groups decorating the sp(2)-hybridized carbon skeleton for a 3D penetration structure were developed. The delocalized (CS)-S-= could optimize the spatial p-electron conjugation and the formation of spatial sp2-hybridization between carbon layers, thereby providing superior electronic and atomic structural properties. The resulting carbon skeleton of hollow carbon spheres containing (CS)-S-= (C5(=)S/HCSs) facilitated an efficient 3D charge transfer channel and exhibited fast electrochemical kinetics. Specifically, compared with the control sample in potassium-ion batteries, the C5(=)S/HCSs anode delivers a desirable reversible capacity of 238 mA h g(-1) at 2.0 A g(-1) after 2000 cycles and a high rate capability of 158 mA h g(-1) at 10.0 A g(-1), accompanied by an order-of-magnitude greater electronic conductivity and ionic diffusion coefficient. This finding offers valuable insights into the design of 3D spatial charge transfer in the carbon skeleton for achieving fast reversible ion storage kinetics.