Microstructure regulation of resin-based hard carbons via esterification cross-linking for high-performance sodium-ion batteries

Abstract

Phenolic resin (PF) is a common carbon precursor with low cost and rich carbon content. However, PF-derived carbon is often characterized by a relatively high degree of structural regularity and small interlayer spaces, resulting in poor electrochemical Na-storage ability. In this work, 3,4,9,10-perylene-tetracarboxylic acid-dianhydride (PTCDA) was introduced in PF to regulate the PF-derived carbon microstructures by an esterification cross-linking reaction to improve their Na-storage performance. The integration of PTCDA efficiently enhanced the thermal stability of the resin molecular chain, eliminated defects, and limited the growth of the graphitized domain during the carbonization process, allowing the representative PPFC-1–6–1200 to have an expanded interlayer distance of 0.394 nm but a lower specific surface area of 4.8 m² g⁻¹. When being used as an anode material for sodium-ion batteries (SIBs), PPFC-1–6–1200 delivered a reversible capacity of 308.7 mA h g⁻¹ with an initial coulombic efficiency (ICE) of 77.9%, much superior to the pristine PF-derived carbon materials with a limited capacity of 163.3 mA h g⁻¹ and an ICE of 73.9%. Moreover, PPFC-1–6–1200 exhibited excellent cycling and rate performance with a capacity retention of 90.4% during 300 charge/discharge cycles at 0.5 C, suggesting that PTCDA modification is an effective method to regulate the microstructure and improve the electrochemical sodium storage properties of carbon materials.