Abstract
A hybrid aluminum/hydrogen/air cell system is developed to solve the parasitic hydrogen-generating problem in an alkaline aluminum/air battery. A H2/air fuel cell is integrated into an Al/air battery so that the hydrogen generated by the parasitic reaction is utilized rather than wasted. A systematic study is conducted to investigate how the parasitic reaction and the added H2/air cell affect the performance of the aluminum/air battery. The aluminum/air sub-cell has an open circuit voltage of 1.45 V and the hydrogen/air sub-cell of 1.05 V. The maximum power density of the entire hybrid system increases significantly by ∼20% after incorporating a H2/air sub-cell. The system maximum power density ranges from 23 to 45 mW cm−2 in 1–5 M NaOH electrolyte. The hybrid system is adaptable in concentrated alkaline electrolyte with significantly improved power output at no sacrifice of its overall efficiency.
[Display omitted]
•A self-sustaining hybrid cell system consisting of an Al/air battery and a H2/air fuel cell.•Effectively utilizing the H2 generated by the parasitic reaction rather than dumping it.•Investigating the Al parasitic reaction with mixed potential theory and practical experiments.•The system is adaptable in concentrated alkaline electrolytes without efficiency degradation.•Room temperature operation with system power density higher than direct alcohol fuel cells.