Lignin-based hard carbon as anode for sodium-ion batteries: the impact of chemical and morphological structures
Hao Zhang
Åbo Akademi University
Sodium-ion batteries are garnering attention as potential alternatives to lithium ones due to the abundant and low-cost sodium sources. Hard carbon anode exhibits disordered structure and larger interlayer spacing, facilitating better intercalation and accommodation of the larger sodium ion. This study explores lignin-derived hard carbon (LHC) from various grades, emphasizing the impact of its chemical composition and morphological characteristics. Comprehensive analyses described its inherent carbon-rich structure and inter-unit linkages, revealing that the presence of oxygen-containing groups, and distinctive distributions of microporous channels play important roles in capacitance. A possible mechanism was proposed to explain the effects of lignin chemistry on LHC morphology and its sodium storage during thermochemical conversion through electrochemical evaluation. This study lays a foundation for enhancing LHC anodes by chemical modification and morphological regulation of lignin.