Hard carbon-encapsulated cobalt chalcogenides derived from waste apricot seed testa biomass: High performance anode electrode materials for Na-ion storage

Anode materials are crucial in sodium-ion batteries (SIBs), and the advancement of low-cost, high-capacity, and cycle-stable anode materials is a primary objective in the progression of sodium-ion batteries. Carbon, derived from biomass has emerged as a prominent anode material for energy storage devices, attributed to its costeffectiveness and environmental sustainability. Given their limited capacities at elevated current densities, it is essential to create biomass-derived composites incorporating other components with high theoretical capacities. This study successfully embeds Co3O4, Co9S8, and Co3Se4 cobalt chalcogenide nanoparticles onto hard carbon derived from the biomass of waste apricot seed testa (WAST). Hard carbon coating reduces or inhibits the dissolution of Co3O4, Co9S8, and Co3Se4 cobalt chalcogenides in the electrolyte, thereby preventing capacity loss. The synthesized Co3O4@HC-WAST, Co9S8@HC-WAST, and Co3Se4@HC-WAST electrodes demonstrate excellent cycling stability and rate performance when test as sodium-ion battery anodes. The capacity of the best anode material, Co3Se4@HC-WAST, is maintained at 307.8 mAh g- 1 (5 A g- 1) after 750 cycles with 99 % Coulombic efficiency. This study outlines a method for the preparation and comparison of the electrochemical performance of composite hybrid materials comprising hard carbon and cobalt chalcogenides.