Entropy‐Engineered HEO/Fe, N‐CNT Bioanode via Flash Joule Heating: Accelerated Electron Harvesting and Directed Geobacter Enrichment for High‐Power Microbial Fuel Cells

Abstract

Abstract Extracellular electron transfer (EET) at the microbe‐anode interface remains a critical bottleneck in microbial fuel cells (MFCs). While high‐entropy oxides (HEOs) show promise for enhancing anode kinetics, conventional synthesis methods yield poor interfacial integration and fail to elucidate entropy‐driven EET mechanisms. Herein, an entropy‐engineered bioanode fabricated via ultrafast flash Joule heating (FJH) is reported, which uniformly anchors HEO nanoparticles (Fe─Co─Ni─Cr─Mn─O) onto vertically aligned Fe, N‐doped carbon nanotubes grown on carbon cloth (HEO/Fe, N‐CNTs/CC). This design synergizes CNT conductivity with HEO pseudocapacitance, achieving a record power density of 3.76 W m −2 , surpassing the state‐of‐the‐art HEO anode by 9.6% and bare carbon cloth by 2.2‐fold. The entropy‐broadened conduction bands and strengthened cytochrome adsorption (ΔE ads = −3.20 eV) reduce the electron tunneling distance to 2.47 Å, as revealed by DFT calculations. Furthermore, the anode promotes Geobacter enrichment (71% biofilm abundance) and riboflavin secretion, facilitating dual direct and mediated EET pathways. This work establishes entropy modulation as a universal strategy for high‐performance bioelectrochemical systems, opening avenues for sustainable energy harvesting and environmental sensing.

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Identifiers

DOI

10.1002/smll.202511164

Journal

Small

Year

2025