Tetrahydrofuran stabilizing aqueous zinc ion batteries through adsorption and hydrogen bonding modulation

Aqueous zinc ion batteries (AZIB) are considered to be one of the most powerful substitutes for the next generation of energy storage devices due to their high theoretical specific capacity, high safety, and low cost. However, AZIB is limited by Zn dendrites and side reactions during cycling, resulting in low coulombic efficiency and poor cycle stability. In this study, 5 % tetrahydrofuran (THF) was introduced into 2 M ZnSO4 electrolyte as an electrolyte additive to improve the AZIB performance. Differential capacitance fitting, theoretical calculation and XRD tests show that THF can adsorb on the surface of Zn anodes to regulate the crystal orientation of Zn metal. Raman and FTIR tests show that THF can also inhibit dendrite growth and side reactions by destroying the hydrogen bond network in electrolyte. Therefore, the THF leads to a stable cycle of over 5300 h at a discharge regime of 1 mA cm−2, 0.5 mAh cm−2 and over 950 h at a higher current density and area capacity of 2 mA cm−2, 2 mAh cm−2. Furthermore, the capacity retention rate of δ-MnO2||Zn full battery reaches 93.63% after 1000 cycles under a current density of 1 A g−1, significantly higher than the 70.55% without THF addition. This strategy provides a simple and low-cost method to solve the common issues of AZIBs.