Development on solid polymer electrolyte water electrolysis technology for high current density and energy efficiency

Mitsubishi Heavy Industries, Ltd. (MHI) has been participating in the sub-task of WE-NET Project since 1993 to develop the solid polymer electrolyte water electrolysis technology. The ultimate goal of the WE-NET Project is to build a hydrogen energy system on a worldwide scale. In this project, water electrolysis plays an important role as the conversion technology of electrical energy to hydrogen energy. Compared with other technologies, the water electrolysis technology using solid polymer electrolyte can be expected highly promising because this technology can ensure a high energy efficiency and a high purity of hydrogen gas. MHI has been conducting the fundamental research on this technology using membrane electrode assembly made through the nonelectrolytic plating. 50cm(2) and 200cm(2) cells were used in the experiments for the elevation of cell performance. The improvement of cell components, especially the material and structure of current collector, decreased the cell electrolytic voltage. As a result, the energy efficiency data at 80 degrees C were increased to 84% at 1A/cm(2) and 73% at 3A/cm(2).