A potentially implantable glucose fuel cell with Raney-platinum film electrodes for improved hydrolytic and oxidative stability

We present an improved abiotically catalyzed glucose fuel cell, intended as energy harvesting tissue implantable power supply for medical implants. The fuel cell is constructed from a Raney-platinum film cathode deposited on a silicon substrate with micro-machined feedholes for glucose permeability, arranged in front of a Raney-platinum film anode. A novelty is the application of platinum for both electrodes and the complete abdication of hydrogel binders. This overcomes the limited stability against hydrolytic and oxidative attack encountered with previous glucose fuel cells fabricated from activated carbon particles dispersed in a hydrogel matrix. During performance characterization in phosphate buffered saline under physiological concentrations of glucose and oxygen the diffusion resistance to be expected from tissue capsule formation was taken into account. Despite the resulting limited oxygen supply, the Raney-platinum fuel cells exhibit a power density of up to (4.4 ± 0.2) μW cm−2 at 7.0% oxygen saturation. This exceeds the performance of our previous carbon-based prototypes, and can be attributed to the higher catalytic activity of platinum cathodes and in particular the increased oxygen tolerance of the Raney-platinum film anodes.