(Invited) Effect of Additive Species on the Nucleation and Growth Process on Zn Negative Electrode Surface

Abstract

Zn is one of the promising candidates as negative electrode materials for next-generation secondary batteries, especially those for large capacity applications such as grid-scale energy storage. While the Zn has numbers of attracting features such as crustal abundance, applicability of aqueous system, etc., which enable to realize the secondary batteries with high performance and safety with lower cost, the major drawback is evolution of irregular morphology called mossy structure with highly filamentous features at the electrode surface during charge-discharge cycles. Unlike the conventional dendritic growth which proceeds under diffusion-limited conditions, formation of the mossy structure takes place without such a condition. At the same time, it has been reported that the growth of these irregular structures could be suppressed by applying metallic species as additives to form uniform electrodeposition [1]. We have investigated formation process of the mossy structure on the Zn anode surface, focusing on its initial stage in combination with the additive effects such as Pb and Sn [2]. In this presentation, we will introduce the results of our research on the nucleation and growth process of the mossy structure through experimental analysis and computational modeling. For the theoretical calculation, we attempted to develop multi-scale simulation model by employing density functional theory (DFT) and kinetic Monte Carlo (KMC) approaches [3], and the results will be described focusing on the effects of the metallic additives. This work is financially supported in part by MEXT/JSPS Grant-in-Aid for Scientific Research No. 21H01642. [1] For example, F. Mansfeld, S. Gilman, J. Electrochem. Soc. 117, 1328 (1970); Y. Ito, M. Nyce, R. Plivelich, M. Klein, D. Steingart, S. Banerjee, J. Power Sources, 196, 2340 (2011). [2] For example, T. Otani, M. Nagata, Y. Fukunaka, T. Homma, Electrochim. Acta, 206, 366 (2016); T. Otani, Y. Fukunaka, T. Homma, Electrochim. Acta, 242, 364 (2017). [3] Y. Onabuta, M. Kunimoto, S. Wang, Y. Fukunaka, H. Nakai, T. Homma, J. Phys. Chem.C, submitted.