Electricity generation property in portable direct formate fuel cells (DFFCs) with polyacrylamide hydrogel

Hydrogel is a type of polymer with three-dimensional network structure, which possesses an internal porous cross-linked structure, good liquid absorption, retention capacity, ion conductivity, and provides stable and rich ion transport paths. Their unique properties guarantee the hydrogels as a transformative platform for next-generation miniaturized electronics. In the study, hydrogel is creatively adopted as the multifunctional electrolyte component instead of membrane, and a novel portable direct formate fuel cell is proposed. The polyacrylamide hydrogels are prepared using a free radical polymerization method, and the liquid retention and ionic conductivity are specifically characterized. A portable fuel cell with the above functional hydrogel is fabricated by integrating the functions of fuel/electrolyte storage, supply and ion-transport. It provides a maximum power density output of 25.31 mW⋅cm −2 and a limiting current density of 145.67 mA⋅cm −2 . The design simplifies the complexity of the fuel cell system, and provides a promising way to power the micro electronic devices.