Low-cost manganese dioxide semi-solid electrode for flow batteries

Summary Manganese dioxide is abundant, low-cost, and has the potential to be utilized as a semi-solid electrode for long-duration energy storage technologies such as flow batteries. However, the more stringent pumping requirements of semi-solid electrodes compared to the electrolytes of all-liquid flow battery might limit their techno-economic feasibility. Here, we developed a rechargeable MnO2 semi-solid electrode, performed electrochemical and rheological characterizations, and bottom-up techno-economic analysis of the Zn-MnO2 semi-solid flow battery (SSFB) system. The high power needed for pumping (ranging from 8% to 50% of the power output) leads to a system with high cost of power. Using our experimental results, we suggest strategies to minimize the pumping power requirement for Zn-MnO2 SSFB. As a result of the low cost of its chemical constituents, we show that a Zn-MnO2 SSFB can be cheaper than Li-ion and vanadium redox flow battery solutions for long discharge durations (e.g., >24 h per cycle).