Atomic layer-deposited nucleation layers to control zinc morphology and suppress hydrogen evolution

Abstract

Aqueous zinc (Zn) batteries are among the most promising candidates for safe, low-cost, and sustainable grid-scale energy storage. However, their practical application is significantly constrained by inhomogeneous Zn electrodeposition and the competitive hydrogen evolution reaction (HER). Here, we introduce an electrodeposition architecture to mitigate these challenges. Using atomic layer deposition, we coat the copper current collector with ZnO and Al 2 O 3 nanofilms—positioned below the plated Zn. Our strategy marks a significant departure from previous works in which thin films are situated above Zn foil to function as artificial solid electrolyte interphases. Notably, we achieve substantial performance improvements with our 2-nm-thick ZnO coatings, including long cycle life (>1,400 cycles) and high Coulombic efficiencies (>99.8%). Our mechanistic investigation suggests that these improvements arise from HER suppression and controlled Zn morphology. This work offers an interface engineering approach to fundamentally understand Zn nucleation and growth processes. We anticipate that our electrodeposition architecture could be applied to enhance the cyclability of other aqueous battery systems.