Zinc-ion batteries come with many advantages, such as an abundance of zinc crust, affordance price tag, matured recycling technology, ability to store a mass amount of power, as well as the use of water-based electrolytes instead of the highly flammable organic solvents. However, there is still a long way ahead for the particular technology to attain commercialization, and now Swiss scientists could possibly take the first step in such direction.
Zinc batteries, while possessing numerous advantages, are also relatively flawed. For instance, the water-based electrolytes would generate hydrogen in electrodes amidst high-voltage charging, which consumes electrolytes and lowers battery performance, and could lead to excessive pressure in batteries that will result in hazards. Another issue is the sharp zinc sediments formed throughout the charging process that will penetrate battery separators, which could lead to risks of short circuit and battery malfunctions.
Scientists have thought about using salt as an alternative to lower the water content of water-based electrolytes, which would however result in sticky electrolyte, as well as slow down charging and discharging speed. In addition, a lot of the salt being used contains the toxic and harmful fluorine.
ETH Zürich has thus joined hands with multiple research institutions in an attempt to seek for the optimal level of salt concentration for water-based zion-ion batteries.
The research team, through computer simulation, came to a conclusion that the optimal result is actually a relatively lower level of salt electrolyte at 5-10 water molecules in positive ions of salt. Research staffs also adopted the environmentally friendly acetate. Dario Gomez Vazquez, first author of the thesis, commented that an optimal acetate concentration will significantly reduce electrolyte consumption and prevent dendrite formation, and the new method would also accelerate the speed of charging and discharging.
The research team has started testing the new battery in the laboratory, and will see if they could produce a larger battery next. Zinc-ion batteries, if optimistic, could be applied on grid-grade energy storage systems and residential solar energy storage systems in the future.
(Cover photo source: shutterstock)