Anthracite-based expanded graphite as anode materials for sodium-ion batteries with exceptional sodium storage performances

High-value materialized clean utilization of coal-based anode materials for sodium-ion batteries (SIBs) with large reversible capacity and rapid kinetics are the direction of green and low-carbon economic development. Herein, anthracite-based expanded graphite (AEG) was prepared via a liquid-phase oxidation intercalation-rapid thermal reduction method by employing homemade anthracite-based graphite (AG) as anode materials for SIBs. The unique morphological structure of AEG provides superior structural stability and sodium storage behavior dominated by capacitive adsorption, which enhanced reaction kinetics during the intercalation/decalcification of Na+. Consequently, the AEG anode for SIBs demonstrated a high initial reversible specific capacity of 326 mAh g−1 at 30 mA g−1 and still maintained a specific capacity of 91 mAh g−1 at a high rate of 10 A g−1. Furthermore, the as-prepared sample presented excellent cycling stability, maintaining a specific capacity of 152 mAh g−1 after 1000 cycles at a rate of 1 A g−1, with a capacity retention rate of 80 %. This work presents a broad and promising potential for the greening of energy sources and environmental protection.