Rechargeable Nickle-Zinc Batteries Safer Than Lithium-Ion Counterparts, Claim Researchers

Scientists have developed a safer alternative to fire-prone lithium-ion batteries, which are common in household devices such as smartphones and laptops.

Researchers at the US Naval Research Laboratory (NRL) developed the nickel-zinc (Ni-Zn) batteries in which a three-dimensional (3D) Zn "sponge" replaces the powdered zinc anode, or positively charged electrode, traditionally used.

With 3D Zn, the battery provides an energy content and rechargeability that rival lithium-ion batteries while avoiding the safety issues that continue to plague lithium.

"The 3D sponge form factor allows us to reimagine zinc, a well-known battery material, for the 21st century," said Debra Rolison from NRL's Advanced Electrochemical Materials group.

Zinc-based batteries are the go-to global battery for single-use applications, but are not considered rechargeable in practice due to their tendency to grow conductive whiskers (dendrites) inside the battery, which can grow long enough to cause short circuits.

"The key to realising rechargeable zinc-based batteries lies in controlling the behaviour of the zinc during cycling," said Joseph Parke, lead author of the research paper published in the journal Science.

"Electric currents are more uniformly distributed within the sponge, making it physically difficult to form dendrites," said Parke.

With the benefits of rechargeability, the 3D Zn sponge is ready to be deployed within the entire family of Zn-based alkaline batteries across the civilian and military sectors, researchers said.

"We can now offer an energy-relevant alternative, from drop-in replacements for lithium-ion to new opportunities in portable and wearable power, and manned and unmanned electric vehicles, while reducing safety hazards, easing transportation restrictions, and using earth-abundant materials," said Jeffrey Long from NRL.