Cation/Anion Cointerference Strategy: Boosting the Na-Storage Performance of a Pitch-Derived Carbon Anode

Pitch stands out as a promising carbon precursor owing to its abundance, cost-effectiveness, and high carbon content. However, raw pitch-derived carbon generally shows typical characteristics of soft carbon, with a highly graphitized framework and narrow interlayer spacing that hamper Na-ion storage. Here, a novel cation/anion cointerference approach is introduced to steer both the microcrystalline order and closed-pore architecture of pitch-derived carbon with the assistance of zinc acetate, driving a controlled transformation from soft to hard carbon. Compared to pristine pitch pyrolytic carbon (PC), the optimal modified sample, with abundant closed pores and an increased pseudographitic phase, exhibits a significantly improved Na-storage capacity from 87.7 mAh g⁻¹ to 262.6 mAh g⁻¹, along with a remarkable initial Coulombic efficiency of 86.5%. When paired with a commercial O3-NaNi1/3Fe1/3Mn1/3O₂ cathode, the assembled Na-ion full cell achieves a reversible capacity of 339.8 mAh g⁻¹, and the energy density can reach 263.1 Wh kg⁻¹ based on the mass of the cathode and anode, demonstrating the promising prospect of the fabricated pitch-derived carbons. This work offers a novel perspective on the synergistic mechanism of microcrystalline structure and closed pores for Na-ion storage, and opens new avenues for designing efficient carbon anodes for practical sodium-ion batteries.