Abstract

Co-regulating hydrogel anode properties via a multi-level engineering strategy • Achieves 5.97 W m −2 power density and 0.87 Ω charge transfer resistance • UV-triggered sulfur exposure enriches Geobacter and rewires metabolic pathways. • Direct and mediated electron transfer are synergistically enhanced. • Selectively enriches Geobacter and activates co-metabolism. The efficiency of extracellular electron transfer (EET) is fundamentally limited by sluggish kinetics and unfavorable bio-interfacial environments in microbial electrochemical systems. Here, we report a multi-level engineering strategy that couples V-doped MXene with a combined liquid‑nitrogen freeze-thaw and ultraviolet (UV) post-treatment to co-engineer the electrode's electronic structure and bio-interfacial environment. The optimized PPSV-UN anode enables a microbial fuel cell (MFC) to achieve a remarkable power density of 5.97 ± 0.03 W m −2 and a low charge transfer resistance of 0.87 Ω. This improved performance can be attributed to a synergistic effect: V-doping enhances the electrocatalytic activity and promotes ordered PEDOT chains assembly, while the post-treatment remodels interfacial structure and promotes sulfur exposure. The resulting anode was associated with a distinct microbial community, including a marked enrichment of Geobacter to 71.54% (a 26.3% higher than that of the control), together with a predicted increase in functions related to sulfur metabolism and the TCA cycle. These changes may help explain the accelerated electron flux and enhanced EET performance. In parallel, density functional theory (DFT) calculations further support enhanced electronic coupling of cytochromes and flavins at the remodeled interface, indicating the establishment of a more favorable cooperative electron-transfer pathway. This work provides a viable strategy to improve MFC anode performance through coordinated regulation of interfacial electronic properties and microbe-electrode interactions.