Hybrid porous carbon/polypyrrole composite from recycled coffee grounds as an active electrode material for lithium-ion batteries

Abstract

This study introduces a hybrid composite of carbonized coffee grounds (CCG) and polypyrrole (PPy) as a sustainable and high-performance electrode material for lithium-ion batteries (LIBs). The composite was synthesized using a simple wet method and a controlled carbonization process. The synthesized material was characterized using FTIR and Raman spectroscopy to confirm its structural features and interactions. The CCG/PPy hybrid composite demonstrated outstanding electrochemical properties, including a high specific capacity of 503 mAh g⁻¹ after 200 cycles at a current density of 1 A g⁻¹, surpassing other biomass-based anode materials. Furthermore, it exhibited rapid charge/discharge kinetics (up to 2 A g⁻¹) and exceptional long-term cycling stability. These results are attributed to the synergistic combination of CCG's porous structure, which enhances ion transport, and PPy's conductive network, which improves charge transfer. This work highlights the potential of biowaste-derived materials, such as CCG, in advancing next-generation energy storage technologies by providing sustainable and efficient solutions for LIB applications.