Current-dependent coupling behaviors inspired wide-current cyclable Zn metal anodese

Abstract

Aqueous zinc metal batteries (AZMBs) provide a safe and cost-effective solution to meet the future demand for large-scale energy storage applications. Stable cycling of the Zn metal anode (ZMA) within a wide current range from 0.2 to 10 mA cm−2 is considered one of the most critical requirements to enable AZMBs. However, current studies show that ZMAs may cycle at either high- or low-current densities, but it is difficult to simultaneously achieve stable cycling at this wide current range. Herein, we study the current-dependent coupling interactions among plating, stripping, and corrosion of ZMAs. We reveal that low-current plating/stripping of Zn leads to unfavorable morphological and crystallographic evolution, which results in serious surface corrosion and rapid failure. In contrast, high-current plating/stripping of Zn can enrich its highly stable (002) facets and form localized high-concentration electrolyte layers with solvated aggregates, which consequently suppresses hydrogen evolution reaction, dendrite formation, and surface corrosion. By understanding these current-dependent coupling behaviors, we develop a high-current-engineered Zn anode that enables long-term cycling across a wide current range, including a record-breaking cycling of 4500 h at 0.2 mA cm−2. This work offers new fundamental insights and a feasible engineering strategy to significantly boost the stability of ZMAs.