Abstract
Sodium-ion batteries are emerging as a promising and cost-effective alternative to lithium-ion batteries for large-scale applications. Among various anode materials, hard carbon has become a preferred choice for sodium-ion batteries. This study focuses on synthesizing hard carbon from bio-waste cherries and investigating the impact of nitrogen doping strategies on its electrochemical performance. Using urea as a precursor, post nitrogen doping was found to enhance the structural properties of hard carbon, facilitating better penetration of sodium ions into its internal structure. The results revealed that post nitrogen doping significantly improved the capacity of hard carbon, increasing it from 206 mAh g⁻¹ to 274 mAh g⁻¹ at a current density of 20 mA g⁻¹. Additionally, the post nitrogen-doped hard carbon demonstrated an impressive capacity of 110 mAh g⁻¹ at a high current density of 1 A g⁻¹. These findings underscore the potential of nitrogen doping in optimizing hard carbon for sodium-ion battery applications.