Rational design and modification strategies for pitch-derived carbon anodes for use in sodium-ion batteries

Abstract

Sodium-ion batteries (SIBs) require low-cost and scalable anodes for large-scale energy storage, yet graphite exhibits limited Na-storage capability because of its narrow interlayer spacing and unfavorable Na⁺ intercalation. Pitch-derived carbon systems are attractive in this context because pitch is abundant, inexpensive, processable, and leads to a high carbon yield. However, direct carbonization of pitch usually promotes mesophase ordering and dense carbon frameworks, resulting in insufficient active sites, limited plateau capacity, and sluggish Na-storage kinetics. Focusing specifically on pitch-derived carbon systems, this review summarizes recent progress in pitch-derived carbon anodes for SIBs through four representative modification strategies: porous-structure engineering, molecular crosslinking, heteroatom doping, and composite carbon formation. These approaches enable the regulation of microstructures, pore architectures, defect distribution, and interfacial chemistry, thereby improving reversible capacity, initial coulombic efficiency (ICE), rate capability, and cycling stability. We further discuss the remaining challenges and future directions for the rational design of pitch-derived carbon anodes for practical SIBs.