Answer: We considered several key factors in designing the power source for the Airing device: power per weight and volume, ease of manufacture, cost, and environmental impact. The Zinc-air battery was the clear winner in all categories.
The Zinc-air battery provides about ten times more stored energy in the same space as the same-sized Lithium-ion battery. In fact, a rechargeable Lithium-ion battery that could last through the night would make the device too heavy for convenient and comfortable use, our primary concern.
Zinc-air is a proven and inexpensive technology. It was used for years in Polaroid film packages and can be manufactured cost effectively using the roll to roll process. And unlike some of the other caustic, more corrosive, battery technologies, the Zinc-air is environmentally benign — basically a common metal and soap.
A future design may use a power source that is rechargeable without being excessively bulky or heavy. We would all welcome such an improvement. But today, Zinc-air is the best choice to get a working Airing device into the hands of those who are desperately seeking relief from traditional CPAP machines.