Innovative Multielement Modification of Pitch-Derived Two-Dimensional Carbon Nanosheets as Anodes for Superior Performance Sodium-Ion Batteries

The development of advanced anode materials for sodium-ion batteries (SIBs) using pitch-based carbon materials has the advantages of low cost, high electrical conductivity and easy structural modification. In this research, various well-established modification techniques for petroleum pitch are integrated, including the use of recrystallized NaCl as molten salt template, pretreatment and high-temperature carbonization under a pure oxygen atmosphere, and the introduction of heteroatoms (N and S) by hydrothermal methods. The resulting two-dimensional carbon nanosheets with multielement modification exhibit enhanced Na⁺ storage properties, thereby bringing higher cycling stability and superior rate performance. Due to its specific structure and chemical composition, NS-P-OPDC exhibited a high reversible capacity of 406.77 mAh g^-1 at a current density of 100 mA g^-1 and a superior rate performance of 193.20 mAh g^-1 at a current density of 3 A g^-1 after being applied to the anode of SIB half-cell. Especially, a capacity retention of 97.7% was still achieved after 4000 cycles. Meanwhile, the full-cell assembled by Na₃V₂(PO₄)₃ (NVP) cathode and NS-P-OPDC anode could provide a reversible capacity of 235.30 mAh g^-1 at a current density of 300 mA g^-1. This application proves to advance petroleum pitch-based high-performance electrodes toward greater efficiency in electrochemical energy storage.