Hay Think learned from the Dalian Institute of Chemical Physics, Chinese Academy of Sciences that the researchers of this institute have made new progress in the research of long-life zinc-based flow battery composite ion-conducting membranes. Cycle life. Related research results were published in "German Applied Chemistry".
The ion-conducting membrane is one of the key components of the battery, and a reasonable membrane structure design plays an important role in improving the cycling stability of the battery. Researchers Li Xianfeng and Zhang Huamin of the Dalian Institute of Chemistry, Chinese Academy of Sciences introduced boron nitride nanosheets with high thermal conductivity and high mechanical strength into the porous base film. That is, a layer of boron nitride nanosheets was added to the base film to prepare composite ions Conductive membrane. Among them, on the one hand, the boron nitride nanosheets facing the negative electrode can evenly distribute the surface temperature of the electrode, and adjust the zinc deposition shape from a sharp "dendritic" to a soft "fries"; on the other hand, the boron nitride nanosheet The film has high mechanical strength, which can effectively block over-grown sharp zinc dendrites and avoid damage to the membrane material. The synergy of these two aspects can significantly improve the cycle life of the battery.
According to reports, the alkaline zinc-iron flow battery assembled with the membrane did not significantly decay when it was operated stably for 500 charge-discharge cycles for nearly 800 hours at a current density of 80 mA per square centimeter, even at 200 mA. Under the condition of square centimeter current density, the energy efficiency also exceeds 80%, which has important reference significance for the regulation of zinc anode in zinc-based batteries.
Zinc-based flow battery energy storage technology has good application prospects in the field of distributed energy storage due to its low cost, high safety, and environmental friendliness. However, when zinc ions are reduced at the negative electrode, they easily deposit to form metal zinc with different shapes such as dendritic, mossy, and layered. Among them, the destructive dendritic metal zinc, namely "zinc dendrite", grows to a certain extent. It will puncture the ion-conducting membrane and cause the battery cycle life to decrease.
Previously, the research team found that through the charge characteristics of the membrane material, the zinc deposition direction and morphology can be adjusted, thereby greatly improving the cycle stability of the zinc-based flow battery.