Flow batteries are a promising energy storage solution. However, the footprint and capital cost need to be further reduced for flow batteries to be commercially viable. The flow cell, where electron exchange takes place, is a central component in flow batteries. Improving the volumetric power density of the flow cell (W/L_cell) can reduce the size and cost of flow batteries. While significant progress has been made on flow battery redox, electrode and membrane materials to improve energy density and durability, conventional flow batteries based on planar cell configuration exhibit a large cell size with multiple bulky accessories such as flow distributors, resulting in low volumetric power density. In this talk, I will introduce a new co-axial microtubular (CAMT) flow battery cell configuration that significantly improves volumetric power density by reducing the membrane-to-membrane distance by almost 100 times and eliminating completely the bulky flow distributors. Using zinc-iodide chemistry as a demonstration, our CAMT cell shows peak charge and discharge power densities of 1322 W/L_cell and 306.1 W/L_cell compared to average charge and discharge power densities of < 60 W/L_cell and 45 W/L_cell of conventional planar flow battery cells. The battery cycled for more than 220 hours, corresponding to > 2,500 cycles at off-peak conditions. Furthermore, the CAMT cell has been demonstrated to be compatible with zinc-bromide, quinone-bromide, and all-vanadium chemistries. The CAMT flow cell represents a device-level revolution to enhance the volumetric power of flow batteries and potentially reduce the size and cost of the cells and the entire flow battery.

Publication:

https://chemrxiv.org/engage/chemrxiv/article-details/62070e98bd05a04ae103fa7e