Mildly-catalytic mediation of pseudographitic domain to boost hard carbon toward advanced sodium storage

Hard carbons (HCs) are of industrial prospect as the promising anodes of sodium-ion batteries, but the precise tailoring of carbon microstructure desirable for energy storage remains a tremendous challenge. In this work, we propose an effective mildly-catalytic mediation strategy to regulate the pseudographitic structure of resin-derived HCs toward high-efficiency sodium storage. The appropriate introduction of Mn²⁺ is revealed to promote the formation of pseudographitic carbon domains with enlarged carbon interlayer spacing and decent structural defects. Consequently, the as-optimized HC obtains an impressive specific capacity of 340 mAh g⁻¹ at 0.02 A g⁻¹, superior rate property of 181 mAh g⁻¹ at 1 A g⁻¹, and remarkable cycling durability over 2000 cycles. The enhanced performance and charge storage mechanism are systematically explored by various kinetic characterizations and in situ Raman testing. This study affords a new design tactic to finely tune the pseudographitic structure of HCs for advanced sodium energy.