A Double-Functional Additive Containing Nucleophilic Groups for High-Performance Zn-Ion Batteries

Aqueous zinc-ion batteries (AZIBs) have attracted attention for their low cost and environmental friendliness. Unfortunately, commercialization has been hampered by several problems with dendrite growth and side reactions. Herein, we select sodium tartrate (TA-Na) as a dual-functional electrolyte additive to enhance the reversibility of AZIBs. The tartrate anions are preferentially adsorbed on the Zn surface, and then the highly nucleophilic carboxylate will coordinate with Zn²⁺ to promote the desolvation of [Zn(H₂O)₆]²⁺, leading to uniform Zn deposition on the beneficial (002) plane and inhibiting side reactions and dendrite growth. Consequently, the Zn|Zn cells show a long-term cycling stability of over 1500 cycles at 0.5 mA cm^-2. Moreover, the Ta-Na additive improves the performance of Zn||MnO₂ full cells, evidenced by a cycling life of 1000 cycles at 1 A g^-1 under practical conditions with a limited Zn anode (negative/positive capacity ratio of 10/1) and controlled electrolyte (electrolyte/capacity ratio of 20 μL mAh^-1).