Researchers at the University of New South Wales and the National University of Singapore have developed a scalable solution to overcome the rechargeability challenges of aqueous rechargeable zinc battery technology.

The new method is expected to solve a significant problem with the aqueous rechargeable zinc battery technology, which is the ability to recharge, which has so far proven to be limited due to the amount of corrosion suffered by the battery’s zinc metal electrode.

The researchers developed a solution that introduces a very small concentration (1 volume%) of non-toxic additive molecules in the battery electrolyte. This addressed the corrosion issue and effectively reduced the dendritic zinc deposits that otherwise short-circuit the battery cell.

Using small pouch-type cells, the team demonstrated that about 1 kWh of electricity storage per 30 kg weight (or ~30 Wh/kg) can achieve the same storage per 16 kg weight (~60 Wh/kg) in a further scaled-up setup with a high-voltage cathode.

The method helped achieve a 5- 20 times improvement in the battery cycle life under conditions suitable for beyond-lab-scale development, equivalent to pushing the lifetime from a few months to over three years.

The AZB technology has emerged as an alternative to Li-ion batteries (LIBs) in electric vehicles and renewable energy storage, owing to absolute safety, resource abundance of raw materials, potential low cost, and competitive energy densities.

The zinc batteries are also sought after due to their high energy storage capacity of the mineral and the use of water-based or aqueous electrolytes. However, when the zinc corrodes and forms dendrites, the battery’s life and performance are lowered.

“A safe and affordable aqueous rechargeable zinc battery technology will accelerate renewable energy integration, enable smart grid technologies for better management of energy distribution, load balancing, and demand response, support the establishment of microgrids powered by renewable energy sources for remote communities, and may provide a cost-effective and reliable storage option for industries like mining, construction, and telecommunications,” said Dipan Kundu, corresponding author, and researcher, UNSW.

In renewable energy storage, the application of LIBs has posed a huge challenge of cost and fire risks, but with the use of aqueous rechargeable zinc batteries that use an aqueous salt solution electrolyte, it has emerged as a promising alternative owing to its safety, raw material abundance, affordability, and competitive energy densities.

Last April, a team from ETH Zurich developed an environmentally friendly salt concentration for water-based zinc-ion batteries to make them more commercially viable.

Previously, researchers from the Indian Institute of Technology, Madras, also developed a model to make zinc batteries an economical replacement for LIBs in EVs.