Low cost, environmentally friendly aqueous Zn batteries have great potential for large-scale energy storage. In our previous work, we found that the intercalation of zinc ions in the cathode materials is challenging and complex ^{[1, 2]}. In this talk, we will try to clarify it by showing the critical role of structural H₂O on Zn²⁺ intercalation into the V₂O₅ framework ^[3].

Our latest results demonstrate that the H₂O solvation of Zn²⁺ largely reduces its effective charge and thus its electrostatic interactions with the V₂O₅ framework, effectively promoting the diffusion of solvated Zn²⁺. Benefited from the ‘lubricating’ effect, the aqueous Zn battery shows a specific energy of ~ 144 Wh kg^-1 at 0.3 A g^-1. Meanwhile, it can maintain an energy density of 90 Wh kg^-1 at a high power density of 6.4 kW kg^-1 (based on the cathode and 200% Zn anode), making it a promising candidate for high-performance, low-cost, safe, and environmentally friendly energy storage device. Such a ‘lubricating’ effect in Zn batteries could be applicable to other multivalent metal ion-based batteries for further improving the energy storage performance, and could also shed light on discovering new battery materials.

Reference

[1] H. Pan, Y. Shao, P. Yan, Y. Cheng, K. S. Han, Z. Nie, C. Wang, J. Yang, X. Li, P. Bhattacharya, Nature Energy 2016, 1, 16039.

[2] P. He, M. Yan, G. Zhang, R. Sun, L. Chen, Q. An, L. Mai, Advanced Energy Materials 2017, 7.

[3] M. Yan, P. He, Y. Chen, S. Wang, Q. Wei, K. Zhao, X. Xu, Q. An, Y. Shuang, Y. Shao, K. T. Mueller, L. Mai, J. Liu, J. Yang, Advanced Materials, 1703725, doi: 10.1002/adma.201703725.