Detrimental Effects of Metal Foil’s Surface Imperfections on Metal Plating/Stripping and Facile Solutions

Abstract

Rechargeable metal batteries have attracted great interest and are considered one of the most promising high-energy density storage systems. These devices benefit from the large specific volumetric capacities and high specific gravimetric capacities of metal anodes. Foils or sheets are the most common form of anode for metal batteries since they are massively manufactured and readily accessible. But short circuits from dendrites grown on metal foil anodes can dramatically decrease the cycling stability and lead to premature failure of the batteries.Homogeneous metal plating/stripping is the key to avoiding dendrite formation. And the surface uniformity of metal electrodes is crucial for the initial nucleation and growth, which greatly affects the subsequent deposition. Here, we show that manufacturing-induced defects, including surface imperfections such as a roughened surface, orange peel features, microcracks, scratches, or fold lines, and unpolished edges from cutting can all promote local dendrite growth, leading to drastically decreased cycling stability of the demonstrated Zn metal batteries and K metal batteries. Polishing the metal electrodes on both sides and edges is shown to be effective to improve the electrochemical homogeneity of the metal anode and extend the cycling lifespan by over 700% in the demonstrated Zn metal cells. Finally, we demonstrate a simple and rapid surface passivation strategy that drastically increases the tolerance of such defects in Zn metal batteries. Also, we proposed a scalable, easily automated, and facile metallic K manufacturing with robust performance in K metal batteries.Since such imperfections are ubiquitous in commercially available metal foil products. Our results remind researchers about the significant detrimental effects of these very common defects introduced by metal manufacturing and processing, which should be taken into consideration evaluating metal battery performances. Furthermore, we call for research efforts to develop effective strategies that are scalable, easily automated, and cost-effective to increase the tolerance of batteries over such defects, which will be very important for large-scale, cost-effect energy storage hubs.References Pan He and Jiaxing Huang. "Detrimental effects of surface imperfections and unpolished edges on the cycling stability of a zinc foil anode." ACS Energy Letters, 2021,6,1990-1995.Pan He and Jiaxing Huang. "Chemical passivation stabilizes Zn anode." Advanced Materials, 2022, 34, 2109872.Pan He and Yang Xu. "Facile manufacturing potassium metal anode with robust performance". In preparation. Figure 1