Researchers develop rechargeable alkaline zinc batteries

25 July 2022

A research team at the Hong Kong University of Science and Technology has developed a new electrode design that gives recharging capabilities to alkaline zinc batteries, one of the most common types of non-rechargeable batteries used.

A majority of batteries in the current market are not rechargeable, known as primary batteries. They are usually disposed of after a single use, an unsustainable practice that poses serious environmental threats.

Alkaline zinc batteries are cost-effective, safe, and energy-dense devices, but they are limited in rechargeability. When the battery is discharged, zinc particles in the zinc electrode are covered with a thick and non-uniform layer of insulating zinc oxide, causing the battery to lose the electric conductivity it needs for recharging.

To tackle this issue, a research team led by Dr Qing Chen from the Hong Kong University of Science and Technology has developed a nanoporous zinc metal electrode that is capable of stabilising the electrochemical transition between zinc and zinc oxide, successfully turning an alkaline zinc-air coin cell into a rechargeable battery stable for over 80 hours.

The team shaped the zinc into curvy filaments hundreds of nanometers wide and nested it in a freestanding solid with numerous, similarly narrow pores. When the battery is discharged, a thin layer of zinc oxide forms on the zinc filaments, preserving its conductive metallic surface and enabling the zinc electrode to return to its initial structure.

“The needs for batteries are diverse and difficult to be met by a single technology – zinc batteries are finding their niche. We are now working to improve the microstructure of the zinc electrodes so that they can withstand hundreds, and hopefully thousands of repetitions of charging and discharging,” said Chen.

The team’s findings were recently published in Nature Communications.