Abstract

The increasing demand for lithium-ion batteries has intensified the search for sustainable alternatives to conventional graphite anodes. In this work, cotton-derived carbon fibers were prepared from commercial medical-grade cotton wool using a two-step pyrolysis process and investigated as hard-carbon anode materials for lithium-ion batteries. The structural and morphological properties of the prepared material were analyzed using X-ray diffraction, scanning electron microscopy, and transmission electron microscopy, revealing a predominantly amorphous carbon structure with a retained fibrous morphology after pyrolysis. Electrochemical performance was evaluated in CR2032 half-cells by cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic charge–discharge measurements. The prepared hard carbon exhibited characteristic lithium-storage behaviour with irreversible processes during the initial cycle followed by stable reversible cycling. The material delivered a reversible capacity of approximately 780–800 mAh g−1 after 300 cycles at a current density of 100 mA g−1, together with stable Coulombic efficiency and good rate capability. Post-mortem analysis confirmed that the electrode structure remained stable after repeated cycling. The obtained results demonstrate the potential of waste cotton as a renewable precursor for the preparation of high-performance hard-carbon materials and highlight the applicability of biomass-derived carbons for sustainable electrochemical energy-storage systems.

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