Engineering porosity and active sites in peach pit-derived carbon materials for high-performance sodium storage

Abstract

The abundant availability, unique microstructure, and low working potential of biomass carbon materials position them as promising candidates for anode materials in sodium-ion batteries (SIBs). Nevertheless, their practical application is hampered by a low initial coulombic efficiency (ICE) and the presence of impurities, which severely impair their electrochemical performance. Herein, we propose a facile synthesis method for preparing high-capacity biomass carbon materials, achieving a specific capacity of 220.2 mAh g⁻¹ alongside excellent ICE. The biomass carbon materials are derived from cost-effective biomass peach kernel shells through a hydrothermal pre‑carbonization process, followed by activation with NH₄HCO₃. This treatment effectively enhances porosity, modifies interlayer spacing, and increases the number of active sites in the microstructure. The results indicate that NH₄HCO₃ treatment effectively improves both the active sites and the interlayer spacing of the biomass carbon materials, thereby markedly augmenting their sodium storage capacity. Furthermore, we elucidated the sodium storage mechanism characterized by “adsorption-intercalation-filling” using in-situ X-ray diffraction (XRD) and ex-situ Raman spectroscopy. The interface of the solid electrolyte interphase (SEI) membrane was examined using ex-situ X-ray photoelectron spectroscopy (XPS), complemented by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analyses. These results underscore the potential of modified biomass carbon materials as high-performance anodes in SIBs, providing ideas for future research and development in this field.