The nanoelectrofuel (NEF) battery technology is a transformational advancement of redox flow battery concepts, where energy is stored and released through a reversible electrochemical reaction between two electrolytes. As shown in Figure below, the cathodic and anodic electrolytes are stored externally to the battery and circulated through the reactor as required, providing separation between power ratings and energy storage capacity.
The main limitations of traditional electrolyte-based flow batteries in transportation applications are the low energy densities (40-80 Wh/L) due to the limited solubility of redox salts. Instead of redox salts, NEF technology uses stable dispersions of solid cathode and anode nanomaterials in aqueous electrolytes.
Nanoparticle suspensions have significantly higher stability than micron-sized suspensions due to the relative balance between Brownian motion and gravity, and can be prepared with as high as 85 wt.% solid loading. Electrical energy is stored in redox nanoparticles, which in discharge mode undergo a spontaneous electrochemical reaction inside the flow cell stack with cathodic NEF being reduced and anodic NEF being oxidized. The difference between electrochemical potentials for cathodic and anodic redox reactions defines the cell potential. Under steady-state rest conditions, the cathodic and anodic NEFs can be stored separately from the device.
Low viscosity of NEF is critical, as it affects charge/discharge efficiency, power ratings and parasitic losses of the flow battery. Influit Energy’s unique process for preparing and dispersing nanoscale electrode materials in aqueous electrolytes enables low viscosity and high stability of suspensions with high solid loadings, resulting in the energy density of NEF battery being competitive with Li-ions (over 350 Wh/L at system level and operating temperature range from −40C to +80C).
Merging several energy storage concepts (solid battery chemistries in a flowable format) allows NEF to meet energy density targets for transportation and offers a cheaper, safer and environmentally friendly rechargeable energy-storing fluid. The latter positions rechargeable NEF batteries as an alternative to gasoline fuel for transportation as well as for sustainable integration with other renewable energy applications.