Coffee Husk –Derived Activated Carbon/Polyaniline Nanocomposites as High Performance Anode for Microbial Fuel Cell and Supercapacitor

The urgent need for clean and sustainable energy has intensified research into renewable Bioelectrochemical technologies. Here, activated carbon (AC) was derived from coffee husk, an abundant agricultural waste, and combined with polyaniline (PANI) via a one step in situ chemical oxidative polymerization to produce AC/PANI nanocomposites. The synthesized materials were characterized using UV-Vis, SEM–EDS, XRD, FTIR, BET and Raman spectroscopy to investigate its optical, morphological, and structural properties, molecular vibrational states, surface area and structural defects. Electrochemical performance was evaluated using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Electrochemical studies revealed a high specific capacitance of 625 F g -1 at 0.01Vs -1 . When employed as an anode in microbial fuel cells (MFCs), the AC/PANI electrode delivered a maximum power density of 136.25 mWm -2 and a current density of 350 mA m -2 , substantially outperforming PANI (42.88 mW/m², 180 mA m -2 ) and AC ( 36.5 mW m -2 ,150 mA m -2 ).The superior performance arises from the synergistic interaction between PANI and the AC matrix, providing efficient charge transport, abundant active sites, and combined pseudo capacitive and electric double layer behavior. These results highlight coffee husk derived AC as a cost-effective, sustainable, and high performance material for enhancing MFC anode functionality and advancing electrochemical energy storage technologies.