A MXene-based slurry bioanode with potential application in implantable enzymatic biofuel cells

Abstract Enzymatic biofuel cells (EBFCs) have been proposed as a reliable power source for implantable biomedical devices because of their sustainability and biocompatibility. However, the limited reactant concentration in vivo and concerns about bioelectrode fouling and leaking have largely restricted the methods of assembling EBFCs and resulted in unsatisfactory performance. In this study, we design a novel enzymatic slurry bioanode wrapped by a dialysis membrane in which enzymes, electron mediators and nanomaterials are dispersed instead of immobilized on an electrode. Notably, a novel two-dimensional metal carbide nanomaterial, Ti3C2 MXene, is adopted for the first time in EBFCs as a large surface area and highly conductive nanosheet. Using the MXene-based slurry bioanode, a maximum power density of about 320 μW cm−2 and a maximum current density of 2.1 mA cm−2 are generated under flow conditions with phosphate buffer solution containing 5 mM glucose at 25 °C. In addition, a long-term continuous discharge for about 20 days is achieved with a 5 μA discharge current. This prototype is promising for the implantation and longtime operation of EBFCs in vivo.