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Technology Transfer

High Conductivity Single-Ion Cross-Linked Polymers for Lithium Batteries and Fuel Cells

A cross-linked comb-branch structure.

Figure 1. Cross-linked comb-branch structure. Heavy horizontal lines represent the comb-branch backbone, heavier vertical lines the cross-links and the lighter vertical lines the solvating ether side-chains. Anions are fixed to the side chains. Mechanical properties are a function of the backbone structure and cross-link density. Ionic mobility is a function of the solvating groups incorporated in the side chains. The molecular structures are infinitely variable in order to provide optimum properties for both bulk membranes and composite electrodes (MEAs).

The Lawrence Berkeley National Laboratory (Berkeley Lab) Technology Transfer Department licenses a wide range of cutting-edge technologies to companies that have the financial, R&D, manufacturing, marketing, and managerial capabilities to successfully commercialize Lab inventions. It develops and manages an array of partnerships with the private sector.

Because of their wide electrochemical potential, lithium-ion batteries provide the largest energy density for weight. These batteries are used in multiple applications, from laptop computers to cell phones to defense equipment and electric vehicles and are safer for environmental use than conventional batteries.

John Kerr and researchers in the Advanced Energy Technologies Group have refined the lithium-ion battery to make it longer lasting and to improve its performance. Through the use of single-ion, cross-linked comb-branched polymer electrolytes as membranes in lithium batteries, the power performance and energy density of the battery can be increased.

Solid polymer electrolytes have been improved by the creation of single-ion polymer conductors. Single-ion conductors avoid the development of concentration gradients that result in low voltage and low energy capacities upon discharge because the anion is immobilized.

Composite electrodes lithium metal ploymer diagram

The capabilities, materials, and principles used for developing these polymer electrolytes for lithium batteries can be adapted to develop polymer films for fuel cells and electrochromic windows. Kerr's group is developing membranes for fuel cells that can operate at temperatures above 100°C without the need for water in the membrane. This results in significant savings in system complexity and weight that are important considerations for fuel cell-powered vehicles. The new polymer materials also show promise for use in chemical separations, catalysis and sensors, particularly in the the area of biotechnology.

For more information, contact:

  • Technology Transfer Department
  • Lawrence Berkeley National Laboratory
  • MS 90-1070
  • Berkeley, CA 94720
  • (510) 486-6467; Fax: (510) 486-6457

More information about High Conductivity Single-ion Cross-linked Polymers for Lithium Batteries and Fuel Cells.

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