Researchers from Australia and China are working to develop the world's first safe and efficient non-toxic aqueous aluminum radical battery. A team from Flinders University in South Australia and Zhejiang University of Science and Technology in China reports on the first stages of developing these new batteries in a new article published in the American Chemical Society's flagship journal, the American Chemical Journal.
Most batteries contain hazardous materials that can pollute the environment when ended up in landfills or thrown away elsewhere. Substances such as lead, cadmium, and mercury poison people and animals, contaminate soil and water, and they persist in the environment for long periods of time.
The research laboratories of Dr. Kai Zhang of Zhejiang Sci-Tech University and Associate Professor Jia Zhongfan of Flinders University collaborated on the (electrochemical) and battery testing of stabilized free radicals in the most commonly used Lewis acid electrolyte (Al(Otf)3).
The team developed the first aluminum-based battery design that uses a flame-retardant and air-stable water-based electrolyte to deliver a stable voltage output of 1.25V and a capacity of 110mAhg–1 over 800 cycles with only 0.028% loss per cycle.
Professor Jia Zhongfan from Flinders University's School of Science and Engineering hopes to use biodegradable materials to develop pouch batteries in the future, making the products safe and sustainable.
Professor Jia said multivalent metal-ion batteries, including Al3+, Zn2+ or Mg2+, take advantage of abundant elements in the earth's crust and provide much higher energy density than lithium-ion batteries (LIB).
"Aluminum-ion batteries (AIBs), in particular, have attracted significant attention because aluminum is the third most abundant element (8.1%), making AIBs potentially a sustainable and low-cost energy storage system."
However, one of the main challenges currently facing AIB is the slow movement of Al3+ ion complexes, which results in low cathode efficiency of AIB. Organic conjugated polymers are an emerging cathode for AIBs that can solve the ion transport problem, but their battery voltage output performance is still poor.
Stable radicals are a class of organic electroactive molecules that have been widely used in different organic battery systems. The first such product was commercialized by NEC in 2012.
The Jia Laboratory at Flinders University has previously developed basic materials for organic hybrid lithium-ion batteries, sodium-ion batteries and all-organic batteries. These radical materials have never found application in AIBs due to a lack of understanding of their (electro)chemical reactions in electrolytes.