Redox Flow Lithium Oxygen Batteries
Upon discharging, O2 is reduced by dissolved viologen in the electrolyte, with which Li2O2 is formed in the GDT tank in the presence of Li+. Upon charging, Li2O2 in the GDT tank is oxidized by I3-, which releases O2. As such, the discharging product Li2O2 could be remotely formed in the GDT tank and reversibly oxidized in the charging process without depositing onto the cathode inside the cell. Such decoupled reactions of Li2O2 provide great flexibility to circumvent the issues confronted by the conventional Li-O2 batteries. The surface passivation and pore clogging of the cathode resulted from Li2O2 precipitations, which is inevitable in conventional cells, are essentially avoided under the new operation mode. In addition, the capacity of the cathode could be expanded by simply enlarging the size of GDT tank, which is however constrained by the pore volume of cathode and catalysts deposited on it in the conventional Li-O2 batteries. Moreover, as the reaction of O2 in GDT is far apart from the electrodes, the tolerance of the cell towards air would be enhanced as well.
- Q. Huang, et al., Reversible Chemical Delithiation/ Lithiation of LiFePO4: Towards A Redox Flow Lithium-ion Battery. Phys. Chem. Chem. Phys., 15 (2013), 1793-1797.
- F. Pan, et al., Redox Targeting of Anatase TiO₂ for Redox Flow Lithium-ion Battery, Adv. Energy Mater., 4 (2014), 1400567.
- Q. Wang, et al., Redox Targeting of Insulating Electrode Materials: A New Approach to High Energy Density Batteries. Angew. Chem. Int. Ed., 45 (2006), 8197-8200.