Enhancing Li-Ion Battery Anode Performance Through Carbon-Coated Spherical Graphite: Influence of Synthesis Parameters on Electrochemical Behavior

Abstract

In this study, carbon-coated commercial spherical graphite (cSG) was synthesized using polyvinyl alcohol (PVA) as a carbon precursor to improve the electrochemical performance of anode materials for lithium-ion batteries. The coating process involved mechanical stirring and pyrolysis with the optimal synthesis conditions identified as a mass ratio of cSG:PVA = 5:1, carbonization at 900 °C for 60 min in a nitrogen atmosphere. The carbon coating with its amorphous structure effectively preserved the crystalline integrity of the graphite core while enhancing its cyclic stability. Electrochemical evaluations demonstrated that the carbon-coated cSG achieved a specific capacity of approximately 360 mAh/g and maintained excellent cycling stability over 450 cycles, significantly outperforming pristine spherical graphite, which exhibited considerable capacity degradation after 100 cycles. The carbon layer effectively reduced side reactions with the electrolyte, improved lithium-ion diffusion, and mitigated structural degradation during charge-discharge processes. These findings highlight the critical role of synthesis parameters in optimizing the carbon-coating process and demonstrate the potential of PVA-derived carbon coatings as a cost-effective and scalable strategy for enhancing the durability and performance of graphite-based anodes in lithium-ion batteries. This work offers valuable insights for the development of high-performance energy storage systems.