Here, an electron transfer enhanced redox mediator is presented that significantly enhances electron transfer between the host electrode and enzymes, as well as between adjacent enzymes, promoting seamless interfaces through multiple interactions.
Abstract
Biofuel cells (BFCs) offer an eco-friendly route to convert biochemical energy into electricity. However, their performance is hindered by insufficient enzyme immobilization as well as limited electron transfer within the enzymatic electrode. While the incorporation of redox mediators (RMs) into enzyme layers has been shown to improve BFC performance through enhanced electron transfer, progress has plateaued in the last decade. Herein, a major breakthrough is presented realized by a novel strategy that exploits electron transfer-intensified RM layers. Metal nanoparticles covalently bridged between neighboring RMs facilitate electron transfer ubiquitously. Electron transfer characteristics are enhanced not only within the RM layers themselves, but also at the glucose oxidase (GOx)/host electrode and GOx/GOx interfaces. This leads to a remarkable performance boost in the enzymatic anode. A hybrid BFC constructed with innovative anode and Pt-based cathode exhibits a striking combination of high power output (2.3 and 8.5 mW cm−2 at 10 and 300 mmol L−1 glucose, respectively) and exceptional operational stability (≈80% and 47% power retention after 10 days and 1 month, respectively), outperforming all previously reported BFCs by a significant margin.
