Firstly, the energy density of flow batteries is relatively low, which means that in order to achieve the same energy output, the volume and weight of flow batteries will be larger. Secondly, the cost of flow batteries is relatively high, especially the high cost of vanadium resources in all vanadium flow batteries. In addition, although flow battery technology is constantly advancing, the commercial application of flow batteries is still in the development stage compared to mature lithium-ion battery technology. Finally, the flow battery system consists of multiple components such as electrolyte storage tanks, pumps, pipelines, etc., which increases the complexity and difficulty of installation and maintenance of the system. Despite these drawbacks, flow batteries have significant advantages in the field of long-term energy storage. For example, the output power and energy storage capacity of a flow battery can be designed separately, by increasing the number of single cells and electrode area to increase power, and by increasing the volume or concentration of electrolyte to increase power. In addition, the positive and negative active materials of flow batteries only exist in the positive and negative electrolytes, and there is no phase change during charging and discharging. They can be deeply discharged without damaging the battery, thus having a longer cycle life.