Effects of hydrogen bubbles on deformation of zinc anodes at high depth of discharge
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ORIGINAL PAPER
Effects of hydrogen bubbles on deformation of zinc anodes at high depth of discharge Chao Yang 1 & Xinjie Liu 1 & Kai Yang 2 & Yanqing Lai 2 & Kai Zhang 2 & Zhongliang Tian 2 Received: 2 July 2020 / Revised: 1 October 2020 / Accepted: 4 October 2020 # Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract The effects of hydrogen evolution reaction on the deformation of zinc anode which cycles at nearly 100% depth of discharge (DOD) are studied. Results show that the generated hydrogen bubbles during charging process will gather on the surface of the middle of the anode and will cover the ZnO which is produced by the hydrolysis of Zn (OH)42ā and prevent ZnO participation in the charging process. Since the charge-discharge reaction only occurs at the edges of the bubbles, the multiple dissolution and redeposition of the active material results in the formation of a massive ZnO and a very low specific discharge capacity. This finding provides a new perspective for the deformation of zinc anodes of the secondary alkaline zinc-based batteries. Keywords Secondary alkaline Zn-based batteries . Zn anode deformation . Hydrogen evolution reaction . Zn (OH)42ā
Introduction Secondary alkaline zinc-based batteries including Zn-air, Zn-Ni, and Zn-Ag batteries have received extensive attention due to their high safety, chargeability, low cost, and environmentally friendliness [1, 2]. Zn-Air battery is considered to be one of the most potential developing batteries in the future due to its safety, low cost, and especially high power density (1084 Wh kgā1) [3ā5]. Rechargeable Zn-Ni battery is expected to replace Pb-acid batteries and Ni-Cd batteries that contain toxic heavy metals, and it has been greatly developed in recent years [6, 7]. However, for the rechargeable secondary battery, the development of zinc anode is limited by the problems of hydrogen evolution reaction, deformation, and zinc dendrites [8]. Although zinc has relatively high hydrogen evolution overpotential, the lower potential of the anode still causes hydrogen evolution reaction (HER) on the surfaces of current
* Zhongliang Tian [email protected] 1
Anhui Laboratory of Functional Coordinated Complexes for Materials Chemistry and Application, School of Chemical and Environmental Engineering, Anhui Polytechnic University, Beijing Middle Road, Wuhu 241000, China
2
School of Metallurgy and Environment, Central South University, 932 Lushan South Road, Changsha 410083, Hunan, China
collector (silver wire mesh or tinned copper mesh) and conductive carbon to form hydrogen gas bubbles during charging [9, 10]. For secondary batteries, the stability of the structure of the electrode plays an important role in the cycle life of the battery. However, the deformation of zinc anode in the alkaline electrolyte seriously hinders the development of secondary zinc-based batteries. In the past studies, it was generally believed that the HER will decrease the faradaic efficiency and the bubbles will reduce the effective area of the cathode
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