Further studies of a zinc-air cell employing a Zn-PCH (PVA chemical hydrogel) anode

Abstract

The capacity utilization of zinc anode is usually very low in alkaline solution because of extreme dissolution and the passivation of zinc surface. This problem can be substantially overcome by using the composite electrode of Zn-PCH (PVA chemical hydrogel). In this work, PCH hydrogel film coated on the surface of the ZnO particles can reduce the solubility of the zinc and the concentration of the Zn(OH)42−. The cell with the Zn-PCH electrode reached 150 cycles before its capacity fell below 90% of the initial capacity, while the standard cell failed after 150 cycles. Based on the scanning electron microscopy observation of the Zn-PCH electrode, it shows a distribution of big spherical particles to form a loose and porous structure rather than a dense and compact film, which can help zinc electrode to stay in a loose and porous structure. Such texture is definitely in favor of the diffusion of OH− ions, facilitating the utilization of active material. Therefore, the Zn-PCH electrode can effectively improve the cycle performance of the secondary Zn-air battery.