Screening report on cell materials for high-power Li-Ion HEV batteries.

The Battery Technology Department at Argonne National Laboratory is a major participant in the U.S. Department of Energy's Advanced Technology Development (ATD) program. This multi-national laboratory program is dedicated to improving lithium-ion batteries for high-power HEV and FCEV applications. As part of the FreedomCAR Partnership, this program is addressing the three key barriers for high-power lithium-ion batteries: calendar life, abuse tolerance, and cost. All three of these barriers can be addressed by the choice of materials used in the cell chemistry. To date, the ATD program has developed two high-power cell chemistries, denoted our Gen 1 and Gen 2 cell chemistries. The selection of materials for use in the Gen 2 cell chemistry was based largely on reducing material cost and extending cell calendar life, relative to our Gen 1 cell chemistry. Table 1 provides a list of the materials used in our Gen 2 cell chemistry and their projected costs, when produced in large-scale quantities. In evaluating advanced materials, we have focused our efforts on materials that are lower cost than those listed in Table 1, while simultaneously offering enhanced chemical, structural, and thermal stability. Therefore, we have focused on natural graphite anode materials (having round-edge particle morphologies), cathodemore » materials that contain more Mn and less Co and Ni (which can be produced via low-cost processes), lower cost electrode binders and/or binders that possess superior bonding properties at lower concentrations, and lower cost salts and solvents (with superior thermal and oxidation/reduction stability) for use in the electrolyte. The purpose of this report is to document the results of screening tests that were performed on a large number of advanced low-cost materials. These materials were screened for their potential to impact positively on the calendar life, safety, and/or cost of high-power lithium-ion cell chemistries, relative to our Gen 2 cell chemistry. As part of this effort, we developed and employed a set of standard test protocols to evaluate all of the materials. After brief descriptions of the screening test methodologies and equipment, relevant data on each material are summarized in the body of this report. We have evaluated five categories of materials, and the report is organized accordingly. Results will be presented on advanced carbons for anodes, improved cathode materials, new salts and solvent systems, alternative binders, and novel separators.« less