As the demand for green vehicles and power sources increases, researchers worldwide are working to invent new types of batteries that can hold more energy and allow vehicles to drive longer per charge. One of the new battery technologies being explored is a zinc-air battery (ZAB). One big challenge with the ZAB is that the battery can be unstable.
The ZAB can have parasitic or side reactions like dendrite formation and air electrode failure stemming from the use of alkaline electrolytes that can lead to battery failure. Researchers may have solved this issue by developing a novel chemistry for the battery that uses a non-alkaline, water-electrolyte. Researchers say that the new chemistry overcomes parasitic reactions.
The non-alkaline electrolyte uses a previously unknown reversible zinc peroxide chemistry for the battery. The newly developed non-alkaline electrolyte has multiple advantages over the conventional strong alkaline electrolytes. Advantages include a zinc anode that is used more efficiently with a higher chemical stability and electrochemical reversibility.
One researcher on the project said that current zinc-air batteries are utilizing slow four electrons oxygen redox reaction due to water involvement. However, using a Zn-salt with a hydrophobic anion trifluoromethanesulfonate, the team was able to remove water from the air cathode surface, allowing a highly reversible 2e ORR reaction on the air cathode in a diluted, aqueous electrolyte.
Researchers say that the resulting full zinc-air battery can operate stably for 320 cycles and 1600 hrs in an ambient air atmosphere. Researchers are clear that while the ZAB is a potential alternative battery technology with advantages compared to current lithium-ion batteries, the technology requires more research and optimization. One challenge remaining is a water management system to ensure long-term practical operation because the battery works in an open atmosphere allowing electrolyte evaporation.