Metal Organic Framework assisted ionic conductivity in solid polymer electrolyte for application in lithium-ion battery

Solid polymer electrolytes are safer alternatives to the current flammable liquid electrolytes used in lithium-ion batteries. We are using crystalline PEO₆/LiX (X= anion) as the potential polymer electrolyte. In this structure, pairs of PEO chains wrap around each other to form cylindrical tunnels. Inside the tunnel each Li+ coordinates with six ether oxygens. The anions are located outside the tunnel. Low molecular weight PEO₆ has been found to be more conductive than its amorphous counterpart. However, it is not useful for practical applications as at room temperature this structure is like viscous liquid. Although increasing molecular weight improves the structural stability of PEO₆, it doesn’t improve conductivity. High molecular weight PEO₆ chains fold into lamellae, preventing direct pathway for lithium ion conduction. We propose that incorporating high aspect ratio nanofillers, containing lewis acidic surface sites, with PEO₆ can resolve the issue. Using metal organic framework as the nanofiller, we have obtained conductivity greater than 10^-5 S/cm at 30°C.

Reference:
Gadjourova, Z., Andreev, Y. G., Tunstall, D. P., & Bruce, P. G. (2001). Ionic conductivity in crystalline polymer electrolytes. Nature, 412(6846), 520.