Optimizing Amphoteric Cellulose Additives with Complexation-Adsorption Mechanisms to Stabilize the Zn Anode.

Abstract

The growth of Zn dendrites and interfacial side reactions are two critical challenges impeding the commercial application of aqueous zinc batteries (AZBs). The amphoteric electrolyte additive is considered a convenient and efficient strategy to stabilize the Zn anode. However, most studies overlook the critical impacts of their charge compositions and the corresponding mechanisms on Zn²⁺ electroplating behavior. Here, we use amphoteric cellulose as an exemplary research object, as the number of positive/negative groups can be easily and effectively controlled. We elucidate in detail the interplay between the complexation and adsorption mechanisms of the amphoteric cellulose additive in AZBs. Specifically, the amphoteric cellulose additive not only guides and regulates Zn²⁺ deposition but also forms a uniform protective layer on the Zn surface. As a result, the optimal additive enables dendrite-free and side-reaction-suppressed AZBs, leading to a Zn||Zn cell with a high depth of discharge of 68.4%, and a Zn||NH₄V₄O₁₀ cell with a high reversible specific capacity of 310 mAh g^-1. This work demonstrates a promising strategy by elucidating the role of charge composition in electrolyte additive design, advancing the development of stable AZBs.