MICROWAVE PROCESSING OF COFFEE WASTE TO PRODUCE POROUS CARBON MATERIALS AND THEIR USE IN SILICON-CARBON ANODES OF LITHIUM-ION BATTERIES

This paper presents the synthesis of a composite anode material for lithium-ion batteries consisting of graphenelike carbon obtained from coffee waste and silicon. The carbon material was synthesized by microwave carbonation and physical activation using CO₂. This method yields a porous structure with an exceptional specific surface area of 1300 m2/g after physical activation. Such a porous structure is crucial for efficient lithium-ion adsorption, high charge transfer, and improved overall battery performance. The morphology and structure of the material were analyzed using SEM and Raman spectroscopy, which confirmed the formation of highly porous graphenelike carbon. The electrochemical characteristic demonstrated a specific capacity of 350 mAh/g for 160 cycles, indicating excellent long-term stability. Coulomb efficiency remained at 98–100%, demonstrating high reversibility of electrochemical reactions. Electrochemical impedance spectroscopy has revealed a moderate 550 ohm charge transfer resistance for the composite material, which highlights the efficient electron transfer between the material and the electrolyte. These results highlight the potential of microwave carbonation and physical activation of CO₂ to produce high-performance, cost-effective anode materials, paving the way for their application in next-generation lithium-ion batteries.