Synergistic effect of pore structure and crystalline domains enabling high capacity toward non-aqueous rechargeable aluminum batteries

Rechargeable aluminum batteries (RABs) with low cost and high safety have been regarded as a potential alternative to lithium-ion batteries. Despite the widely used graphite materials, the research on hard carbon with abundant sources and low carbonization temperature is rarely reported. Herein, a series of hard carbon materials with different degrees of graphitization is controllably fabricated through a ball-milling method. It is found that surface-specific area and pore structure are significantly affected by ball-milling time. As a result, the as-optimized product with suitable graphitization degree and pore distribution shows a high capacity (125 mAh·g−1 at 200 mA g−1 after 200 cycles) and excellent cycle stability (82.2 mAh·g−1 at 150 mA g−1 after 500 cycles). Such electrochemical performances can be ascribed to the fact that a proper graphitization degree ensures fast electrons transfer between layers, and multi-pores architectures contribute to accelerating ions migration. This work is expected to guide synthesizing a biomass-derived hard carbon via a facile and low-energy method, which may accelerate the practical application of RABs and facilitates the mass production of cathode carbon materials.