Rapid Carbonization of Anthracite Coal via Flash Joule Heating for Sodium Ion Storage

Anthracite coal holds great promise as a prospective anode material for sodium ion batteries. However, traditional preparation methods suffer from prolonged calcination time and significant energy consumption, impeding high-throughput synthesis and structural control of anthracite coal. To address these challenges, we propose an emerging rapid carburization method for anthracite coal utilizing flash joule heating, which enables the removal of noncarbon components within one second at an ultrafast heating rate. Under a jolt of electricity, the prepared anthracite coal exhibits a turbostratic graphite-encased porous carbon structure with larger interlayer spacing than that achieved through high-temperature furnace annealing. The anthracite coal prepared via flash joule heating demonstrates high reversible capacity (209 mAh g–1 at 0.05 A g–1) and significantly enhanced rate capability (reaching 115 mAh g–1 at 1 A g–1), with no capacity decay observed after 500 cycles in a sodium-ion half-cell. These findings highlight the potential of flash joule heating in rapid and efficient synthesis of anthracite coal, offering new possibilities for the development of high-performance anode materials in the next generation of sodium-ion batteries.