Self‐Powered Embedded‐Sensory Adjustment for Flow Batteries

Abstract Flow batteries (FBs) are one of the most promising strategies for large‐scale energy storage, in which the flow rates of electrolytes are critical to the redox reaction efficiency. However, low‐power and energy‐efficient strategies to effectively monitor and adjust the flow rates of FBs are great challenges. Here, a liquid metal based thin‐film and self‐powered triboelectric sensor (LM‐TS) to monitor and adjust the real‐time electrolyte flow rates in FBs is developed. By integrating the LM‐TS with a peristaltic pump (flow rate control unit in FB), the flow rates of electrolytes can be converted into readable electrical output signals. Furthermore, a logical and a control module are adopted to adjust the flow rates of electrolytes automatically after receiving those electrical signals, which are available to guarantee the optimal working condition of FBs. Benefiting from the high conductivity and outstanding ductility of ultrathin LM film, the self‐powered LM‐TS is endowed with high sensitivity, short response time (9.1 ms), and remarkable cyclic stability (> 20000 cycles) without affecting the normal operation of FBs. This is the first prototype of self‐powered adjustment sensor for FBs, which is readily extended to scaled‐up FB equipment for intermediate trial and large‐scale energy‐storage demonstration.