Regulating interfacial chemistry of hard carbon anodes by in situ coupling strategy for high-rate sodium-ion batteries

Hard carbon (HC) has garnered attention as a promising anode material for sodium-ion batteries (SIBs), however, it suffers from low specific capacity and rate capability. Herein, an in situ interfacial regulation strategy is proposed to strengthen Na + transportation in HC by anchoring pitch onto phenolic resin spheres. The cross-linking condensation between phenolic hydroxyl groups of phenolic resin and hydroxymethyl groups of pitch during carbonization favors the interfacial interlocked structure of HC; the decomposition products of zinc acetate inhibitor attenuate the strong π–π interactions between aromatic chains in phenolic resin and pitch, suppressing the open-pores and the graphitization due to the carbon layer rearrangement. These facilitate the interfacial Na + transport kinetics and stable Na + (de)intercalation of HC. It is demonstrated as an anode material of SIBs to deliver high capacities of 353 mAh g −1 at 50 mA g −1 and 252.5 mAh g −1 at 1000 mA g −1 , with capacity retention of 96% after 1500 cycles. This work highlights the crucial role of the interfacial regulation and micropore manipulation in durable sodium storage of HC. • The cross-linking condensation between phenolic resin and pitch induces an interfacial interlocked structure. • The release of ZnO attenuates the π-π interactions to reduce the formation of open-pores. • Synergistic effect of interfacial regulation and pore manipulation enhances sodium storage capacity.