Improving the Energy Density and Performance of Detachable Redox Flow Batteries

In this project we aim to develop a novel iron-titanium redox flow battery with two detachableelectrolyte storage tanks. Iron-titanium batteries cost $80/kWh for energy storage—lower than$369/kWh of lithium-ion batteries and $399/kWh of vanadium flow batteries. An iron-titaniumbattery employs no self-igniting materials and its electrolytes are comprised of ~60% water— deeming it fire safe. As a result iron-titanium batteries could be ideal devices for fire-safe low- cost and long-duration (>10 h) storage of clean energy generated in rural areas.This proposal also wants to explore the possibility of using freights and pipelines fortransporting clean electricity from countrysides to end-users in metropolises. A flow batteryseparates electrolyte reservoirs from two electrodes. When it is charged electricity is converted tochemical energy which is stored in iron (II) and titanium (IV) salts that are dissolved in twoaqueous solutions respectively. Such water-based electrolytes can be transported from a rural areavia for example trucks trains boats or pipelines to another battery cell in a different locationwhere charged electrolytes will be pumped through the electrode compartments of the secondcell—converting chemical energy back to electricity. The spent electrolytes comprised of iron (III)and titanium(III) will be brought back to the original cell in the rural area for recharging. If itworks this strategy could solve the transmission and distribution problem of renewable energy— potentially transforming rural areas into the energy production centers of the U.S. and enabling theexport of clean energy to the larger global market.A detachable battery can also power an agriculture vehicle for its continuous operation in fields.The recharge of the battery will be achieved by simply exchanging electrolyte storage tanks.The major goals of this project include: (1) increasing the energy density of charged electrolytesby varying the composition of iron and titanium water solutions respectively for reducingelectrolyte transportation costs; and (2) optimizing the cell structure for improved batteryperformance.