Lithium batteries

Lithium conduction (Rechargeable batteries): One of the main thrusts in the design of more efficient lithium rechargeable batteries is to replace the typically polar organic liquid electrolytes by polymer electrolyte membranes to increase the durability, safety and flexibility. The optimal polymer electrolyte must meet certain requirements: a) High conductivity (s>10-4 S/cm) at ambient and sub-ambient temperature, b) good mechanical strength, c) appreciable transference number, d) thermal and electrochemical stabilities and e) better compatibility with the electrodes. It is generally accepted that, due to the nature of the lithium solvation within polymeric matrices, the ion transport is strongly coupled to the macromolecule segmental motion. Therefore, highly conductive materials tend to have poor mechanical properties.

Our goal is to develop mechanically robust lithium conducting polymers based on either liquid-crystalline rod coil block copolymers or lithium solvating semi-crystalline polymers containing five-membered heterocycles similar to propylene carbonate. These materials will be used to explore the key factors necessary for ionic transport within “soft” and “stiff” polymeric matrices. Insights from this study can be used to develop durable, highly conductive polyelectrolytes for lithium-ion batteries.

Lithium conductivity of PEG grafted PEI copolymers doped with low (blue, green and pink) and high (red and black) molecular weight lithium salts.

Doyle, R., P. Chen, X., Macrae, M., Srungavarapu, A., and Granados-Foci, S., Poly-(ethylene-

imine)-based polymer blends as lithium single-ion conductors. Macromolecules,   2014,47,

3401. Link

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