Lithium-ion batteries are the frontrunners in the battery world. This 50-year-old technology forms the electronic backbone of billions of mobile devices around the world and is the current front-runner to power the world’s electric vehicle future. But that doesn’t mean there’s no competition.
For example, when it comes to renewable energy storage, other concepts like iron-air batteries (which use oxidation to store energy) are potentially better options than the more expensive and highly explosive lithium. There is a possibility. And more options are always being explored. For example, the idea of proton batteries, which use protons separated from water and combined with carbon electrodes, is starting to gain popularity. This is good news because proton batteries do not require rare elements such as lithium. And now scientists at the University of New South Wales (UNSW) Sydney want to take them mainstream.
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“Proton batteries have many advantages,” Sicheng Wu, a PhD candidate at UNSW Sydney, said in a press statement. “However, current electrode materials used in proton batteries, some made from organic materials and others from metals, are heavy and still cost significantly.”
In addition to this cost, the few carbon electrodes that exist have a limited voltage range, and both of these drawbacks currently make proton batteries unsuitable as true lithium-ion replacements. But scientists at UNSW Sydney have developed a new carbon electrode called tetraaminobenzoquinone (TABQ) to solve this problem. The research team started with a small molecule called tetrachlorobenzoquinone (TCBQ). This molecule does not have a redox potential high enough to be a cathode or low enough to be an anode.
So Wu’s team replaced the four chloro groups in the molecule with amino groups (hence the name change), and the resulting lower potential made TABQ a better anode candidate, improving the material’s ability to store protons. I found that it improves. Even when combined with a TCBQ cathode, the all-organic battery can withstand 3,500 full charging cycles, maintains high capacity, and performs well in cold environments. This is a beneficial side effect since battery farms are needed, especially in cold and dark environments. Lithium becomes less efficient when it gets too cold.
Oh, and another bonus is that it doesn’t explode.
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“The electrolyte in lithium-ion batteries is of great concern because it is made of lithium salts, which are flammable solvents,” Professor Chuan Zhao from UNSW Sydney University said in a press statement. “In our case, both electrodes are made of organic molecules with an aqueous solution between them, making our prototype battery lightweight, safe and affordable.”
While TABQ is an excellent anode, the researchers acknowledge that the TCBQ used in the cathode does not have the highest redox potential and needs to be improved next. If proton batteries have any hope of supplanting lithium as the battery of the Green Revolution, much more work will need to be done.
“We designed a very good anode material,” Wu said. “Future work will move to the cathode side. We will continue to design new organic materials with higher redox potential ranges to increase the output voltage of the cells. To facilitate this, we need to develop more efficient energy integration technologies, and our proton battery design is a promising endeavor.”
Darren lives in Portland and has a cat. I write/edit about science fiction and how our world works. If you look hard enough, you can find his previous articles on Gizmodo and Paste.
