Bio-Organic Adenosine with Bilateral Asymmetric Structural Units Remodels Definitive Interfacial Actions for Highly Reversible Zn Metal Batteries

Abstract

Functional groups of organic molecules play their respective advantages in the Zn deposition process, thus bringing significant improvements to the electrochemical performance even at trace additions. In this study, we introduced adenosine (ADS) bio-organic molecules into electrolyte to facilitate the uniform diffusion of Zn2+ and enable the in-situ construction of a zincophilic anode/electrolyte interface by preferential chemisorption of the ADS-amino group on the Zn anode. Automatically, the ADS-hydroxyl group towards the electrolyte bulk will coordinate free water molecules through hydrogen bonding, accelerating the process of Zn2+ extraction from the solvation structure. This interface not only has a strong affinity for promoting Zn2+ dynamic transport and uniform deposition but also acts as a suppressor for side reactions. Consequently, Zn||Zn symmetric cells with a trace amount of ADS additive (5 mM) exhibit an ultra-long lifespan of 3000 h at 2 mA cm-2 and 2 mAh cm-2 and 950 h at a harsh condition of 8.85 mA cm-2 and 8.85 mAh cm-2. A practical rechargeable Zn||NVO pouch cell is assembled, showing a capacity of 140 mAh g-1 and remarkable stability of 96% retention for 300 cycles at 0.5 A g-1.

Keywords: bio-organic additives, anode/electrolyte interface, uniform deposition, anti-side reaction, Zn-metal anodes