Widespread extracellular electron transfer pathways at the interface of bimetallic metal-organic frameworks composite...

Enhancing energy recovery from organic waste using microbial fuel cells (MFCs) remains constrained by inefficient extracellular electron transfer (EET) and unstable interfacial electron flux. Here, a multiscale engineered bioanode is developed by integrating a bimetallic Ni/Co metal-organic framework (MOF) with a conductive polyaniline (PANI) network on carbon felt to improve bioelectrochemical performance. The hierarchical structure provides abundant redox-active sites, continuous conductive pathways, and a favorable microenvironment for microbial colonization, thereby promoting efficient coupling between microbial metabolism and electrode electron acceptance. The optimized system achieves a high power density of 2265 mW m^-2 (318 % higher than pristine carbon felt) and a coulombic efficiency of ∼ 81 %, demonstrating enhanced substrate-to-electricity conversion. Importantly, the introduction of pseudocapacitive charge buffering mitigates the mismatch between microbial electron generation and electrode electron acceptance, resulting in stabilized electron flux under dynamic conditions. Microbial community analysis reveals enrichment of electroactive bacteria and suppression of methanogenic pathways, indicating effective regulation of microbial metabolism toward electricity generation. This study highlights a coupled bio-abiotic interfacial engineering strategy for improving both efficiency and stability in MFC systems, providing new insights into sustainable wastewater-to-energy conversion.