Highly Reversible Zn Metal Anode Enabled by Sustainable Hydroxyl Chemistry

Abstract

Enhancing Zn anode reversibility with sustainable chemistries is urgent for unlocking rechargeable Zn metal battery technology to complement Li-ion batteries and meet the growing demand for sustainable energy storage. However, conventional practices in electrolyte design which address anode irreversibility through altering the Zn2+ solvation shell often rely on costly concentrated chemicals1-2.In this work, we demonstrate a sustainable and cost-effective electrolyte design strategy by using methanol as a solvent exemplar. The designed electrolyte exhibits unprecedented Zn reversibility combined with high depth of discharge (Coulombic efficiency (CE) >99.5% with 50% Zn utilization and a dendrite-free behavior >1800h) at 25°C due to the determinant interphasial chemistries enabled by the hydroxyl group. Moreover, the Zn anode also shows a high CE >99.5% with 20% Zn utilization at -40°C when supported by a desirable electrolyte bulk transport property. Excellent performance is demonstrated in the Zn || metal-free organic cathode full cells in a wide temperature range. The microscopic characterization and modeling identify the mechanism of unique interphase chemistry and its functionalities as the key factors responsible for dictating reversible Zn chemistry.Reference E. Blanc, D. Kundu, L. F. Nazar, Joule 2020, 4, 771–799.Ma, M. A. Schroeder, O. Borodin, T. P. Pollard, M. S. Ding, C. Wang, K. Xu, Nature Energy 2020, 5, 743-749.