Microbial Etching–Driven Ni/PPy Hybrid Anodes for High‐Performance Sediment Microbial Fuel Cells

ABSTRACT The sediment microbial fuel cell (SMFC) is an emerging green technology for renewable energy generation and wastewater treatment. In this study, carbon‐cloth anodes were modified by several methods, including acid, hot‐acid, electrochemical oxidation, nickel (Ni) deposition, polypyrrole (PPy) coating, and a novel microbial‐etching process that utilizes soil and water microorganisms to roughen the electrode surface biologically. The microbial etching created a porous, biocompatible surface that facilitated improved microorganism–electrode interactions and accelerated electron transfer, cutting the SMFC start‐up time from 216 to 12 h. Compared with the unmodified anode (180 mV open‐circuit voltage, 8.5 mW m −2 power density), the etched anode coated with hybrid Ni/PPy achieved 900 mV, 911 mA m −2 , and 892 mW m −2 , respectively, representing nearly two orders of magnitude improvement in power output. Electrochemical impedance spectroscopy confirmed a sharp decline in charge‐transfer resistance (from 7.11 to 1.03 Ω) following microbial etching and Ni/PPy coating. These results demonstrate that biologically driven surface engineering can effectively integrate with conductive polymer–metal hybrids to produce highly active, low‐resistance anodes. The approach offers a sustainable and scalable route for enhancing SMFC efficiency through synergistic microbial–structural modification of carbon‐based electrodes.