Abstract

A laboratory-scale zinc-air cell described previously has been redesigned with the intention of improving its performance. The zinc was present as a packed bed of 600 µm particles and in this concept the electrolyte and particles are replaced with fresh ones at the end of discharge, permitting the use of a monofunctional air electrode. The improved design had a reduced electrolyte volume on the air side of the cell and better electrical connection to the bed of particles, along with more conveniently located conduits for electrolyte flow driven by natural convection. When discharged at room temperature under the Simplified Federal Urban Driving Schedule (SFUDS) regimen (modified to eliminate regenerative braking) the cell yielded energies that were 2.8 times higher than the original cell (Part I). Increasing the cell temperature (up to 55°C) was found to bring further improvements. Natural convection was shown to be necessary for good cell performance.