Technology Outline (Process Description)

The redox flow battery (RFB) design consists of a two-chamber electrochemical cell and redox-active materials dissolved in liquid electrolytes pumped from external reservoirs through stacked porous electrodes for energy conversion. The catholyte and anolyte chambers are separated with an ion exchange or size exclusion membrane.The appealing design of RFBs ensures excellent safety while allowing for decoupled tweaking of the battery’s energy and power output, which is significantly advantageous over Li-ion battery technology. We have developed ferrocene, viologen, and naphthalene diimide-based molecules and polymers for RFB application as an alternative to vanadium-based electrolytes. The synthesized molecules and polymers were dissolved in deionized water with aqueous supporting electrolytes and pumped into the RFB cell test fixture. The cell test fixture consists of gold-coated copper current collectors, Viton gaskets, PTFE flow frames, graphite felt electrodes, graphite plates with serpentine flow channels, and stainless steel end plates. The aqueous RFBs have been tested under galvanostatic and potentiostatic testing regimes. The RFB test setup and results for BTTMPB/FcNCl ARFB, Polymer ARFB, NDI-APSA/NH₄I APRFB, NDI-Zwitter/NH₄I APRFB, NDI-P/NH₄I APRFB are shown in supporting images.