The inhibition of suitable trace electrolyte on hydrogen evolution of zinc anode and the improvement of zinc battery performance

Solving the irreversible loss of Zn metal anodes caused by side reactions such as hydrogen evolution is very important for the application of aqueous zinc-ion batteries (AZIBs). Researchers pay more attention to the construction of interface layer and the adjustment of electrolyte to suppress the side reaction between zinc anode and electrolyte, while ignoring the influence of electrolyte dosage in battery system, which leads to the difficulty in comparing data. Herein, the method of adjusting the dosage of electrolyte in the cell was put forward to obtain the most suitable volume of electrolyte. The results showed that the comprehensive performance of the cell was the best when the volume of electrolyte was 50 μL (E-50) on zinc electrode of 1.13 cm−2. Linear sweep voltammetry and thickness variation during cell cycle showed that E-50 relieved hydrogen evolution. Conclusively, Zn|E-50|Zn exhibited cycling steadily for more than 2000 h at a current density of 5 mA cm−2 and an area capacity of 1 mAh cm−2, showing low voltage hysteresis. Moreover, Zn|E-50|AC capacitors provide a capacity of 70.2 mAh g−1 at a current density of 5 A g−1 and a capacity retention of 94.28 % after 6000 cycles. This work possesses important reference value for scientific research and engineering application of AZIBs.