Multi-channel rod structure hard carbon for high initial Coulombic efficiency and low-potential sodium storage

Abstract

Hard carbon is one of the most promising anode materials that can be commercialized on a large scale for sodium ion batteries due to its resource abundance, cost-effectiveness, and high sodium storage capacity. Nevertheless, the improvement of high initial Coulombic efficiency and high energy density remains an urgent problem to be solved for the commercialization of sodium-ion batteries (SIBs). Herein, poplar wood was used as the precursor to prepare multi-channel rod structure hard carbon via one-step high-temperature thermal decomposition. The results showed that the microstructure and surface chemical composition of poplar-derived hard carbon can be adjusted by changing the carbonization temperature. Due to its unique multi-channel rod structure, suitable d(002)-spacing (0.370 nm) and ultra-low specific surface area (8.9 m2 g−1), the PHC-1600 exhibits a high reversible capacity of 325 mA h g−1 at current density of 50 mA g−1. It shows a capacity of 245 mA h g−1 at low-potential plateau (75 %). At the same time, the PHC-1600 also exhibits a high initial Coulombic efficiency of 88.3 % and good electrochemical property. The ex-situ XRD and CV revealed that PHCs is dominated by intercalation mechanism. This work provides a new perspective from biomass for the development of outstanding electrochemical performance anode materials with highly profitable and environment-friendly.