Rechargeable Alkali and Alkaline Earth Metal-Air Batteries – Potential and Challenges
In order to resolve environmental and sustainable energy concerns, significant efforts are required to find ways to minimise the use of fossil fuels and to shift to renewable energy resources such as solar, wind, and geothermal power generation. The key to success lies in developing reliable large scale high power energy storage devices. The lithiumair battery has been suggested as one candidate because of its exceptionally high energy storage capacity. Non-aqueous metal-air batteries utilising alkali and alkaline earth metal anodes also offer great gains in energy density over the state-of-the-art Li-ion battery. They are also unique power sources because the cathode active material (oxygen) does not have to be stored in the battery but can be accessed from the atmosphere. Moreover, alkali and alkaline earth elements are much more abundant than lithium and therefore would offer a more sustainable energy storage solution for even beyond the long-term. This work is to enable the uptake of this technology by fully analysing its principle and by exploring the application of nanostructured catalytic cathode materials. The potential of alkali and alkaline earth metal-air batteries will be demonstrated by their electrochemical cycling performance and will be compared with the lithium-air battery. The challenging issues will be discussed according to experimental observations.