Liquid metal anode enables zinc-based flow batteries with ultrahigh areal capacity and ultralong duration
Shengnan Wang, Deshuai Yang, Pu Zhang, Yihui Guo, Xingjun Liu, Mingwen Zhao, Jiaxiong Zhu, Pei Li, Xianfeng Li, Jun Fan, Chunyi Zhi
Abstract
Zinc-based flow batteries (Zn-FBs) are promising candidates for large-scale energy storage because of their intrinsic safety and high energy density. Unlike that conventional flow batteries operate on the basis of liquid-liquid conversions, the Zn anode in Zn-FBs adopts a solid-liquid conversion reaction, presenting challenges such as dendrite formation, poor reversibility, and low areal capacity, limiting its long-duration energy storage (LDES) applications. Here, we developed a liquid metal (LM) electrode that evolves the deposition/dissolution reaction of Zn into an alloying/dealloying process within the LM, thereby achieving extraordinary areal capacity and dendrite-free Zn-FBs with outstanding cycling stability. Both Zn-I 2 and Zn-Br 2 flow batteries using LM electrodes exhibited an ultrahigh areal capacity of 640 milliampere-hours per square centimeter, corresponding to an ultralong discharge duration of ~16 hours, thus exceeding the LDES standard defined by the US Department of Energy. This study breaks the solid-liquid working mode of the Zn anode, offering an effective solution for LDES applications with Zn-FBs.