(230j) Does Metal-Organic Framework (MOF) Improve Lithium-Ion Conduction in Crystalline Solid Polymer Electrolytes?

Solid polymer electrolytes (SPEs) are safer alternatives to the flammable liquid electrolytes used in rechargeable lithium-ion batteries. SPEs can be also used with lithium metal as the anode. The theoretical capacity of lithium metal anode is about 10 times higher than the present graphite anode, which is directly proportional to the number of miles that can be driven per charge by an electric car. Liquid electrolytes are incompatible with Li metal anode because of dendrite formation on lithium metal surface during battery recharging.

The most common SPE is poly(ethylene oxide) (PEO) dissolving a lithium salt (e.g., LiClO₄). PEO is popular due to its ability to dissolve lithium salts easily, and commercial availability at a reasonable cost. However, these electrolytes have poor ionic conductivity, which does not meet the performance demands for practical battery applications. It is believed that ion conduction in PEO based electrolytes depends on polymer mobility in amorphous regions, where lithium ions travel by coordinating with the ether oxygens of PEO. Thus, to increase polymer mobility associated conductivity, a considerable amount of research is focused on lowering the glass transition temperature of SPEs. However, this approach compromises the SPE stiffness, which makes it incompatible with lithium metal anode. Crystalline SPEs are promising alternatives to dissociate conductivity from polymer mobility and increase polymer stiffness. The focus of our research is to improve lithium-ion conduction in crystalline SPEs and to achieve that we are incorporating 2D Cu-based metal-organic framework (MOF) as the nanofiller.