Zinc-air batteries are a special class of metal air batteries. In this instance, the anode is zinc metal, and the electrolyte natural seawater. The cathode is oxygen abundant in the environment. So why the need for a special seawater zinc-air battery catalyst, when this works so well?
Why Do We Need a Seawater Battery Catalyst
The team from Central South University and Xi’an Jiaotong-Liverpool University in China, decided to improve the basic design. This was on account of increasing marine electrification, on and below the ocean surface, rich in oxygen.
The current platinum-on-carbon cathodes for these applications tend to fail prematurely. This is is due to chloride ions polluting the seawater, and disrupting oxygen-reduction pathways.
These pathways are the electrochemical reaction channels, whereby the oxygen gains electrons. The seawater pollution hence adversely affects battery efficiency, voltage, and overall stability too.
The researchers from Central South University and Xi’an Jiaotong-Liverpool University, found their solution in a chlorine-modified iron-nitrogen catalyst, that repelled the chloride polluting the seawater. Their modified seawater zinc-air battery catalyst produced three impressive results:
- Very high power at high current output.
- Stable operation for at least 200 hours.
- A strong candidate for metal-air batteries.
Broader Applications For This Discovery
The Interesting Engineering article that we link to below, speaks of far broader implications. The writer views the discovery as a ‘materials-by-design playbook, for turning the most abundant anion in the ocean, chloride, from a poison into a performance descriptor.’
The catalyst could, for example, help deliver flexible pouch batteries operating directly in the ocean. The benefits could be wide-ranging, including sensors on floating buoys, and unmanned underwater vessels far below.
We can also imagine this seawater zinc-air battery catalyst, making a great contribution to off-grid water desalination. Interesting Engineering suggests the method could use 30% less energy than conventional reverse osmosis.
More Information
Storage Batteries On The Ocean Blue
Battery-Like Nodules Produce Oxygen in Ocean
