Nanostructured Block Copolymers for Lithium Batteries and Biofuels Purification

Nanostructured block copolymers enable the design of membranes with optimized transporting channels for a variety of applications. This presentation addresses the use of these membranes to transport lithium ions in polymeric lithium battery electrolytes, and to separate biofuels such as ethanol and butanol from dilute fermentation broths where they are produced. Previous studies of electrolytes showed an inverse correlation between ionic conductivity and shear modulus: increasing conductivity invariably resulted in a decrease in the shear modulus. Similarly, previous studies of alcohol-selective membranes showed an inverse correlation between alcohol separation factor (ratio of alcohol concentration in the exiting stream to that of the incoming stream) and total flux: increasing the separation factor invariably resulted in a decrease in total flux. Block copolymer membranes do not suffer from these inverse correlations. Practical implications of our discoveries for enabling safe rechargeable batteries and second generation biofuels will be discussed. A large fraction of energy and materials that we use today are derived from industries that consume non-renewable resources. The two projects described here may enable a gradual transition toward to a more sustainable approach.