Guiding Zn Uniform Deposition with Polymer Additives for Long-lasting and Highly Utilized Zn Metal Anodes

The parasitic side reaction on Zn anode is the key issue which hinders the development of aqueous Zn-based energy storage systems on power-grid applications. Here, a polymer additive (PMCNA) engineered by copolymerizing 2-methacryloyloxyethyl phosphorylcholine (MPC) and N-acryloyl glycinamide (NAGA) was employed to regulate the Zn deposition environment for satisfying side reaction inhibition performance during long-term cycling with high Zn utilization. The PMCNA can preferentially adsorb on Zn metal surface to form a uniform protective layer for effective water molecule repelling and side reaction resistance. In addition, the PMCNA can guide Zn nucleation and deposition along 002 plane for further side reaction and dendrite suppression. Consequently, the PMCNA additive can enable the Zn//Zn battery with an ultrahigh depth of discharge (DOD) of 90.0 % for over 420 h, the Zn//active carbon (AC) capacitor with long cycling lifespan, and the Zn//PANI battery with Zn utilization of 51.3 % at low N/P ratio of 2.6. Regulating the interactions between zwitterionic polymer additive and Zn anode can construct an in situ formed uniform protective layer on Zn metal to resist side reactions and guide the Zn even deposition and nucleation along 002 plane, thus rendering the symmetrical Zn//Zn battery and Zn full devices with great performance at high Zn utilization.image

Automated summary

The parasitic side reaction on the Zn anode has been a major obstacle in developing aqueous Zn-based energy storage systems for power-grid applications. In this study, a polymer additive called PMCNA was used to regulate the Zn deposition environment, leading to effective inhibition of side reactions and dendrite growth. The PMCNA forms a protective layer on the Zn metal surface, repelling water molecules and resisting side reactions. By controlling the interaction between the zwitterionic polymer additive and the Zn anode, a uniform protective layer can be formed, resulting in improved performance of Zn//Zn batteries and Zn-based devices.