Challenging Chemical Batteries

While reading “3-D Printing with Ionic Liquids,” it came to my mind that the principal problem with batteries remains their recycling ( C&EN, Dec. 1, 2014, page 5). Chemical batteries, although cheap in manufacturing, are highly taxed in many countries for environmental concerns. I’m referring to the Zn/MnO₂ Leclanché cell with acid (NH₄Cl) electrolyte and the corresponding alkaline cell with KOH electrolyte, which are commonly used to power electronic equipment.

However, most of the electric energy produced in the form of such cells perishes on the way to the end user because the zinc is corroding slowly in the electrolyte even in the absence of an external electric circuit.

Hence, these batteries, after six to 12 months of storage time, contain a fraction of their original charge and must be sold for a fraction of their original price. At the end, every battery produced ends up as chemical waste to be recycled.

On the other hand, dry-store zinc-based batteries with separated electrolytes have been known for a long time and used for military applications. The electrolyte is contained in a capsule inside the battery, which is broken before use by a short blow of the back of the battery against a hard surface; only then is the electrolyte freed and sucked into the space between the electrodes. Such cells can be stored for an infinite time. Their systematic use would thus lower the environmental impact caused by chemical batteries because stored energy doesn’t perish on the way to the end user and fewer batteries need to be manufactured.

What is clearly needed here is a legal constraint on the manufacturing of zinc-based nonrechargeable batteries so that only batteries with separate electrolyte can be sold.

Edgar Müller
Prilly, Switzerland