Highly Reversible Aqueous Zinc Batteries enabled by Zincophilic-Zincophobic Interfacial Layers and Interrupted Hydrogen-Bond Electrolytes.
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Aqueous Zn batteries promise high energy density but suffer from Zn dendritic growth and poor low-temperature performance. Here, we overcome both challenges by using an eutectic 7.6m ZnCl2 aqueous electrolyte with 0.05m SnCl2 additive, which in situ forms a zincophilic/zincophobic Sn/Zn5 (OH)8 Cl2 H2 O bilayer interphase and enables low temperature operation. Zincophilic Sn decreases Zn plating/stripping overpotential and promotes uniform Zn plating, while zincophobic Zn5 (OH)8 Cl2 H2 O top-layer suppresses Zn dendrite growth. The eutectic electrolyte has a high ionic conductivity of 0.8mScm-1 even at -70C due to the distortion of hydrogen bond network by solvated Zn2+ and Cl- . The eutectic electrolyte enables ZnTi half-cell a high Coulombic efficiency (CE) of >99.7% for 200 cycles and ZnZn cell steady charge/discharge for 500h with a low overpotential of 8mV at 3mAcm-2 . Practically, ZnVOPO4 batteries maintain >95% capacity with a CE of >99.9% for 200 cycles at -50C, and retain 30% capacity at -70C of that at 20C.
author list (cited authors)
Cao, L., Li, D., Soto, F. A., Ponce, V., Zhang, B., Ma, L. u., ... Wang, C.
complete list of authors
Cao, Longsheng||Li, Dan||Soto, Fernando A||Ponce, Victor||Zhang, Bao||Ma, Lu||Deng, Tao||Seminario, Jorge M||Hu, Enyuan||Yang, Xiao-Qing||Balbuena, Perla B||Wang, Chunsheng