Bilateral in-situ functionalization towards Ah-scale aqueous zinc metal batteries

Developing practical technical index of aqueous zinc metal batteries (ZMBs) is crucial to support safe large-scale energy storage. However, the realistic performance demonstration of ampere hour (Ah)-scale aqueous ZMBs under high mass loading and large areal capacity, which is the key to the industrial application of aqueous ZMBs, remains a critical challenge. In this paper, we propose a bilateral in-situ functionalization strategy in response to the issues that face high mass loading and large areal capacity of aqueous ZMBs. A gradient interface of Zn negative electrode was formed by directional adsorption and in-situ decomposition of organic sodium salt electrolyte additive. It avoids the influences from the fluctuation of electrolyte state and positive electrode dissolution, realizing uniform large-capacity plating/stripping in Ah-scale pouch cell. The positive electrode interface was also in-situ modified by electrolyte additive, which not only facilitated ion intercalation but also suppressed positive electrode dissolution through adsorption at the interface, thereby achieving high-loading stability. As a result, the cyclic stability in coin cell maintained more than 4000 cycles at 2 A g−1, underscoring the superior compared to its counterpart. More importantly, the Ah-scale pouch cell can last more than 680 cycles with an accumulated capacity of 319.6 Ah. This work offers a roadmap for designing practical Ah-scale ZMB pouch cells. Large capacity vanadium-based aqueous zinc batteries present significant challenges at both electrodes. Here, authors propose a bifacial in-situ modification strategy to alleviate both severe vanadium dissolution and zinc dendrite growth, thereby enabling large capacity aqueous zinc metal batteries.