Temperature effects on lithium/sodium-ion storage behaviors of hard carbon microspheres derived from phenolic resin as potential anode for rechargeable batteries applications

Abstract

Background

Batteries or electrochemical energy storage devices are dependable substitutes for electrical energy storage systems that rely on fossil fuels and are essential in reducing greenhouse gas emissions. As a result, one of the most promising sustainable materials for energy storage is hard carbon (HC).

Methods

We propose both Li and Na ions storage mechanisms of hard carbon spheres derived from phenolic resin (PRHCs). The characterization and electrochemical analyses of the PRHCs synthesized at different temperatures were performed. The PRHCs at various sintering temperatures from experimental and theoretical calculations were investigated.

Significant findings

The investigation highlighted the role of C=O in determining the electrochemical performance of PRHCs, as well as the relationship between the ratio of micropores and mesopores and Na/Li ions’ storage mechanisms. DFT calculations showed an enhancement in Na/Li adsorption with the existence of C=O in the graphene. The electrochemical performance of PR800, which was obtained after sintering at 800°C, demonstrated the highest reversible capacity of 151 mAh/g after 200 cycles at 1.0 A/g. Both capacitive-controlled and diffusion-controlled mechanisms were found to be significant in Na ion transfer, according to the electrochemical investigation. The as-synthesized hard carbon exhibited potential as anode materials for both Na and Li ion batteries.