Composite fuel cell harnesses diabetic urine to power portable medical devices

With its high urea concentration, diabetic urine has the potential to fuel portable medical devices. However, its complex composition, with larger molecules like leukocytes and glucose, prevents scientists from efficiently using it to generate power. Vera-Estrada et al. developed a paper-based, microfluidic fuel cell that uses a zinc oxide/nickel (ZnO-Ni) catalyst to generate energy from diabetic urine despite its complexity, yielding significantly better performance.

The authors’ ZnO-Ni catalyst oxidized urea in diabetic urine despite its other chemical compounds. The catalyst’s optimal nickel concentration was three percent, which resulted in a maximum voltage, current, and power densities of 0.89 V, 1.18 mA cm⁻², and 0.13 mW cm⁻², respectively, for the diabetic-urine-powered fuel cell.

“Despite the complexity of diabetic urine, the ZnO-Ni catalyst showed good tolerance to blocking active sites caused by larger molecules such as glucose, leukocytes, and calcium oxalate,” author Juan Ramirez said. “The findings demonstrate that diabetic urine enables microfluidic fuel cells to power point-of-care and lab-on-a-chip devices, which are very important for portable healthcare technology.”

To create the fuel cell, the authors used carbon-paper-based substrates, with ZnO-Ni as the anode to reduce oxygen and platinum/carbon as the cathode to oxidize urea in the urine. They measured the fuel cell’s performance using polarization and power density curves and compared its performance at different nickel concentrations and to fuel cells containing non-diabetic urine. The study used human urine, which was analyzed for composition.

The team has identified several areas for further research, including recreating the fuel cell using urine from patients with diseases other than diabetes.

Source: “Power generation using diabetic urine as fuel in a paper-based microfluidic fuel cell with a ZnO/Ni-based composite anode,” by Irma Lucía Vera-Estrada, Andrés Dector, Víctor Manuel Ovando-Medina, Hugo Martínez-Gutiérrez, Zulma Flor Estrella-Chavero, Juan Manuel Olivares-Ramírez, Abraham Israel Calderón-Martínez, Iveth Dalila Antonio-Carmona, and Jimmy Alexander Morales-Morales, Journal of Renewable and Sustainable Energy (2024). The article can be accessed at https://doi.org/10.1063/5.0227713 .