Two-dimensional MoS2 nanosheets constructing highly ion-selective composite membrane for vanadium redox flow battery

A novel double-layer composite membrane with a MoS2-rich layer and a polymer-rich layer is prepared by the method of one-step slow solvent evaporation for vanadium redox flow batteries. The composite membrane is composed of MoS2 nanosheets as protecting layer, providing the membrane with lower VO2+ permeability and excellent chemical stability, and sulfonated modified PBI as substrate, providing high proton conductivity. The introduction of MoS2 nanosheets greatly reduces the area resistance of the PBI-PS/MoS2 membrane (0.42 Omega cm(2)), which is comparable to that of Nafion 212 (0.41 Omega cm(2)). The cell equipped with PBI-PS/MoS2 membrane presents improved coulombic efficiencies and energy efficiencies. At 200 mA cm(-2), a high EE of about 80% is achieved. The cell maintains stable performances for nearly 800 cycles, showing impressive durability. The cell also shows a self-discharge rate of as low as 0.0021 V h(-1). The MoS2 nanosheets layer based composite membrane is promising for VRBs.

Automated summary

A novel double-layer composite membrane composed of MoS2-rich and polymer-rich layers is prepared for vanadium redox flow batteries, providing both protection and high proton conductivity through slow solvent evaporation. The membrane shows improved performance, with reduced area resistance and enhanced coulombic efficiencies and energy efficiencies, making it promising for VRBs.