Construction of small Zn-air batteries by dendrite-free Zn electrodeposition using renewable electricity

In this work, the possibility to make small, handy but efficient Zn-air batteries has been studied. Battery anode has been constructed by dendrite-free Zn electrodeposition on conductive substrates made of either carbon cloth or brass. Brass was an alloy containing 71% Cu and 21% Zn. Zn electrodeposition has been monitored by applying several (negative) electric potentials ranging between 0 and −0.5 V. Dendrite-free deposits were obtained for voltages ranging between 0 and −0.2 V while extensive dendrite formation was observed with voltages equal to −0.5 V. Uniform Zn deposits were obtained by using the brass substrate. Zn electrodeposition could be realized with a renewable electricity source, in particular by using a photocatalytic fuel cell or a photovoltaic cell. The substrate (electrode) with deposited Zn film was subsequently employed as anode electrode in a Zn-air battery and the battery characteristics have been monitored. The procedures followed in this work support solar energy conversion and storage in a Zn-air battery.