Novel hydrogen production and power generation system using metal hydride

• Published in: International journal of hydrogen energy 2015-05, Vol.40 (18), p.6197-6206
• Main Authors: Choi, Bokkyu, Panthi, Dhruba, Nakoji, Masateru, Kabutomori, Toshiki, Tsutsumi, Kaduo, Tsutsumi, Atsushi
• Format: Article
• Language: English
• Subjects: Fuel cell/battery system; Hydrogen production; Metal hydride; Power generation
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2015.03.029

A novel electrochemical reactor for hydrogen production and power generation is proposed based on a fuel cell/battery system. The reactions (hydrogen evolution and oxidation) in the system occur at solid/liquid and solid/gas two-phase boundaries using a metal hydride negative electrode. This leads to high energy efficiency for both hydrogen production and power generation. We thus investigated electrochemical charge/discharge performance at various current densities by fabricating an experimental cell. This cell was composed of negative and positive electrodes with a 1:3 capacity ratio. Hydrogen gas was produced in a linear manner during the charge process and it was completely consumed during the discharge process. The energy conversion efficiencies of hydrogen production and of the complete hydrogen production/power generation process at a current density of 37.0 A/m2 were 98.3% and 79.6%, respectively. These values are higher than those of conventional water electrolysis and/or power generation systems. •Reactions in the system occur at solid/liquid and solid/gas two-phase boundaries.•Metal hydride and nickel hydroxide electrode cell with a 1:3 capacity ratio.•Energy conversion efficiency for hydrogen production was 98.3% at 37.0 A/m2.•Round-trip energy conversion efficiency was 79.6%, at 37.0 A/m2.