Regulating the Interfacial Charge Density by Constructing a Novel Zn Anode-Electrolyte Interface for Highly Reversible Zn Anode.

Aqueous zinc-ion batteries (AZIBs) have attracted considerable attention. However, due to the uneven distribution of charge density at Zn anode-electrolyte interface, severe dendrites and corrosion are generated during cycling. In this work, a facile and scalable strategy to address the above-mentioned issues has been proposed through regulating the charge density at Zn anode-electrolyte interface. As a proof of concept, amidinothiourea (ATU) with abundant lone-pair electrons is employed as an interfacial charge modifier for Zn anode-electrolyte interface. The uniform and increased interfacial charge distribution on Zn anode-electrolyte interface has been obtained. Moreover, the unique Zn-bond constructed between N atoms and Zn2+ as well as the hydrogen bonds are formed among ATU and Ac- anion/active H2 O, which promote the migration and desolvation behavior of Zn2+ at anode-electrolyte interface. Accordingly, at a trace concentration of 0.01 mg mL-1 ATU, these features endow Zn anode with a long cycling life (more than 800 h), and a high average Columbic efficiency (99.52 %) for Zn||Cu batteries. When pairing with I2 cathode, the improved cycling ability (5000 cycles) with capacity retention of 77.9 % is achieved. The fundamental understanding on the regulation of charge density at anode-electrolyte interface can facilitate the development of AZIBs.

Targeted Delivery of Zinc Ion Derived by Pseudopolyrotaxane Gel Polymer Electrolyte for Long-Life Zn Anode.

Aqueous zinc ion battery is a potential alternative for a stationary energy storage system owing to the inherent properties of the Zn anode. However, the Zn anode suffers from serious Zn dendrite due to the uneven Zn plating. Thus, inspired by the nano-drug delivery to the target site of the tumor cell, it would be a promising strategy to introduce targeted delivery of zinc ion in the electrolyte for even Zn plating. Passive targeted transport plays an important role in nano-drug delivery, which presents the nano-drug would be released by the nano-drug carrier based on polymer to the particular target site. As a proof-of-concept, a pseudopolyrotaxane conducting the nano-drug carrier applied in targeted cancer therapy is employed as the gel polymer electrolyte (GPE) for long-life Zn anodes. The pseudopolyrotaxane is formed by the self-assembling of α-cyclodextrin (CD) and poly(ethylene oxide), where the zinc ion can be absorbed and delivered to the target site of the Zn anode benefiting from the hydrogen-bond. Impressively, even Zn plating can be induced by the hydroxyl groups of CD to inhibit Zn dendrite. Moreover, the hydrogen evolution reaction is suppressed by the GPE. Less produced H2 is detected in the GPE, which is demonstrated by the online mass spectrometry. Thus, the Zn||Zn symmetrical cell based on the GPE exhibits a cycling life of 1370 h. Compared to the one based on aqueous electrolyte, Zn||MnO2 battery based on the GPE shows a higher capacity retention. This work is expected to avail the development of the aqueous zinc ion battery.