doi:10.1038/nindia.2018.75 Published online 17 June 2018
Researchers at the Indian Institute of Science Education and Research (IISER) in Pune have developed the chemistry for creation of a rechargeable "green" battery based on hydrogen (H2), widely regarded as the cleanest chemical energy carrier and one of the most abundant elements available in nature.
Musthafa Ottakam Thotiyl and his team took an unusual route to overcome drawbacks such as poor availability, lack of safety, high costs, and environmental incompatibility faced by traditional metal ion batteries. Thotiyl and colleagues Neethu Dargily and Ravikumar Thimmappa have formulated, for the first time, a rechargeable battery chemistry based on hydrogen.
To do this, they substituted the platinum cathode of traditional batteries with a hydrogen storage molecule (quinone) which can capture oxidized hydrogen (or protons) generated at the anode. Since this molecule has the unique ability to both store and release hydrogen in a reversible manner, the device can be recharged multiple times, regenerating the original quinone molecules and hydrogen fuel back at the anode. "This leads to an electrically rechargeable battery based on a virtually non-polluting molecular fuel," the authors report. "Most importantly, we do not need to carry hydrogen all the time with us as we can recharge the device whenever required."
Hydrogen is widely used as fuel in energy conversion devices such as proton exchange membrane fuel cells. These fuel cells generate electricity by the oxidation of hydrogen at the platinum anode and reduction of oxygen (O2) at the platinum cathode. But H2-O2 fuel cells are non-rechargeable and can generate electricity only as long as hydrogen and oxygen are supplied to the system. In other words, one must carry hydrogen to use this device continuously.
The promise of the H2-O2 fuel cell technology has been further thwarted by issues of safety and storage of hydrogen and the necessity of heavy loading of expensive platinum catalysts especially for the oxygen reduction reaction.
Armed with the new chemistry, the IISER team is now making a solid state hydrogen ion battery to provide a green alternative to existing batteries.