Intrinsically Nitrogen-Enriched Biomass-Derived Hard Carbon with Enhanced Performance as a Sodium-Ion Battery Anode

Hard carbons are particularly suitable as negative electrodes for sodium-ion batteries (SIBs). To produce hard carbon particles with better sodium storage performance, such as specific capacity, Coulombic efficiency, and cycling stability, a suitable precursor and preparation strategy must be developed. In this paper, we present a new hard carbon that is created by carbonizing jackfruit seed wastes. Under various high-temperature treatment and pretreatment settings, jackfruit seed wastes have been processed. As the carbonization temperature increased, hard carbon became more graphitized. At the same time, the carbonization temperature had a great effect on how much sodium could be stored reversibly. Structural characterization of the hard carbons produced at various carbonization temperatures revealed variance in their architectures, illuminating the relationship between the capacity increase and the size of the sodium storage-available microspores. The hard carbon (HC) produced at the optimized condition (1200 °C) delivered an improved capacity of more than 221 mA h g–1 with an exceptional cycling stability of 98.8% over 100 cycles and improved rate performance relying on reversible sodium insertion. The existence of naturally occurring nitrogen atoms, the textural characteristics, and Na+ adsorption-insertion into the disordered carbon layers can explain how better Na+-ion storage occurs in developed HCs. Our study offers an environmentally friendly method of turning seed waste into a potential low-cost yet highly efficient anode material for SIBs.