Zinc rechargeable battery gets UL verification

Author: EIS Release Date: Feb 28, 2020

A zinc rechargeable battery, being developed by NGK of Nagoya, Japan, has acquired UL verification based on the UL 9540A standard.

 

NGK’s battery uses zinc as the negative electrode, aqueous solution as the electrolytic solution, and an NGK ceramic separator as a barrier between the positive and negative electrodes.

 

Batteries that employ zinc as the negative electrode have a high energy density. This has allowed zinc batteries to be widely used as single-use, non-rechargeable batteries, such as alkaline batteries and air cells for hearing aids, etc.

 

However, when zinc is used as the negative electrode of a rechargeable battery, the zinc will form dendrites on the negative electrode during charging. The dendrites will then pierce the separator and will cause a short circuit.

 

For many years, this problem has hindered the progress on the commercialization of zinc rechargeable batteries.

 

NGK has solved this problem by developing a highly densified ceramic separator with hydroxide (OH－) ion conductivity.

 

As a result, NGK has succeeded in developing a zinc rechargeable battery.

 

The new ceramic separator developed by NGK allows only the hydroxide (OH－) ions, which are essential for battery operation, to pass, while physically blocking the dendrites, thereby preventing short circuits between the positive and negative electrodes.

 

The separator has thus made it possible for the battery to undergo repeated charging and discharging cycles. This is the first case that a ceramic separator is used for a zinc rechargeable battery.