Reconstructing the Anode Interface and Solvation Shell for Reversible Zinc Anodes
Dongdong Zhang, Jin Cao, Rungroj Chanajaree, Chengwu Yang, Hongwei Chen, Xinyu Zhang, Jiaqian Qin
Abstract
The attractive advantages of the Zn metal anode and water-based electrolyte, such as inherent safety and low cost, endow the zinc-ion batteries (ZIBs) with great potential in the future energy storage market. However, the severe surface side reactions and dendrites affect the service lifespan and electrochemical performance of ZIBs. Herein, a bifunctional electrolyte additive, l -ascorbic acid sodium (LAA), has been added into ZnSO 4 (ZSO) electrolyte (ZSO + LAA) to settle the above issues of ZIBs. On the one hand, the LAA additive tends to adsorb on the Zn anode surface to generate a H 2 O-resistive passivation layer, which can effectively isolate the H 2 O corrosion and regulate the Zn 2+ ion 3D diffusion, thus inducing a uniform deposition layer. On the other hand, the strong adsorption capacity between LAA and Zn 2+ can transform the solvated [Zn(H 2 O) 6 ] 2+ into [Zn(H 2 O) 4 LAA], thus reducing the coordinated H 2 O molecules and further suppressing side reactions. With this synergy effect, the Zn/Zn symmetric battery with the ZSO + LAA electrolyte can deliver a cycle life of 1200 h under 1 mA cm –2, and the Zn/Ti battery also presents an ultrahigh Coulombic efficiency of 99.16% under 1 mA cm –2, greatly superior to the batteries with the ZSO electrolyte. Additionally, the effectiveness of the LAA additive can be further verified in the Zn/MnO 2 full battery and pouch cell.