Homogenizing Zn Deposition in Hierarchical Nanoporous Cu for a High-Current, High Areal-Capacity Zn Flow Battery

• Published in: Small (Weinheim an der Bergstrasse, Germany) Vol. 19; no. 40; p. e2303005
• Main Authors: Li, Yang, Li, Liangyu, Zhao, Yunhe, Deng, Canbin, Yi, Zhibin, Xiao, Diwen, Mubarak, Nauman, Xu, Mengyang, Li, Jie, Luo, Guangfu, Chen, Qing, Kim, Jang-Kyo
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 01-10-2023
• Subjects: Copper; Density functional theory; Deposition; Electric energy storage; Electrodes; Heterogeneity; Metal foams; Nanotechnology; Rechargeable batteries; morphology evolution; hierarchical structures; Zn flow batteries; nanoporous electrodes
• ISSN: 1613-6810; 1613-6829
• DOI: 10.1002/smll.202303005

A Zn anode can offset the low energy density of a flow battery for a balanced approach toward electricity storage. Yet, when targeting inexpensive, long-duration storage, the battery demands a thick Zn deposit in a porous framework, whose heterogeneity triggers frequent dendrite formation and jeopardizes the stability of the battery. Here, Cu foam is transferred into a hierarchical nanoporous electrode to homogenize the deposition. It begins with alloying the foam with Zn to form Cu
Zn
, whose depth is controlled to retain the large pores for a hydraulic permeability ≈10
 m
. Dealloying follows to create nanoscale pores and abundant fine pits below 10 nm, where Zn can nucleate preferentially due to the Gibbs-Thomson effect, as supported by a density functional theory simulation. Morphological evolution monitored by in situ microscopy confirms uniform Zn deposition. The electrode delivers 200 h of stable cycles in a Zn-I
flow battery at 60 mAh cm
and 60 mA cm
, performance that meets practical demands.