Three-dimensional nickel foam based enzymatic electrode and its glucose/O₂ biofuel cell with high power density

A practical strategy is developed to fabricate stable glucose/O₂ biofuel cells with high power density assembled by enzymatic bio-electrodes based on three-dimensional nickel foam. The porous three-dimensional nickel foam is used as a substrate to enhance the enzyme loading, while the reduced graphene oxide and gold nanoparticles decorating on the nickel foam are employed as the direct electron transfer system for bio-anodes and bio-cathodes. The ferrocenecarboxylic acid serves for the mediated electron transfer to further increase electron transfer rate for glucose oxidase electrodes. Covalent bond is employed to immobilize the mediator and enzymes for improving the stability of bio-electrodes and biofuel cells. As the results, the surface glucose oxidase loading reaches to 4.03 × 10−⁷ mol cm⁻² with good enzymatic activity. Additionally, the obtained glucose/O₂ biofuel cells exhibit an outstanding maximum power density of 2.84 ± 0.09 mW cm⁻², with a remarkable long-term operational stability for retaining 85.5% of its performance after 70 days. In human blood, the biofuel cell shows a favorable output performance of 0.39 ± 0.04 mW cm⁻², implying the appropriateness for practical applications.