Facile Surface Chemical Tailoring of Industrial Carbon Waste for Improved Sodium Storage

Abstract

Sodium-ion batteries (SIBs) have emerged as promising supplementary for energy storage devices. Among various anode materials, carbon-based materials have been considered ideal for SIBs due to their excellent electronic conductivity, great mechanical strength, and large surface area. However, the small interlayer distance and slower reaction kinetics significantly limit their practical application in SIBs. The study of carbon materials in SIBs found that heteroatom doping could help enlarge interlayer distance and adsorb more Na⁺ simultaneously. Hence, petroleum coke (PC), an industrial waste, is chosen as a precursor. A straightforward oxidation and carbonization process is employed to introduce oxygen atoms into the carbon skeleton (OPC). The heteroatom-doped OPC exhibits a unique microcrystalline structure comprising both graphitic and disordered regions. This structure improves rate performance and enhances initial columbic efficiency (ICE) for sodium storage. Consequently, it can deliver a better cycling capacity of 209 mAh g⁻¹ at 0.1 A g⁻¹ and a high ICE of 51.3% (vs 66.9 mAh g⁻¹ with ICE of PC 12.6%). This study shows that heteroatom doping and microstructural tailoring of materials derived from petroleum coke provide a viable approach for enhancing the electrochemical performance of SIBs, paving the way for sustainable and efficient sodium storage.