457405 The Next Generation High Power, LiFePO4 Cathode Material

Thursday, November 17, 2016: 8:46 AM
Golden Gate 5 (Hilton San Francisco Union Square)
Maha Hammoud1, Charlie Xu2, Judy Laforest2, Lucy Lee2 and Derek Johnson2, (1)R&D, A123Systems, LLC, Romulus, MI, (2)R&D, A123Systems, LLC.

<span" roman"="Roman"" new="New">The use of lithium-ion batteries for transportation applications can be broken up into two segments, low and high voltage. Low voltage systems encompass applications such as 12 V starter batteries and start-stop platforms, while high voltage systems are generally associated with PHEVs and EVs. Thus, when considering the use of rechargeable lithium-ion batteries in the transportation industry, and the development of active materials for this industry, it is important to consider the application to be served. For example, low voltage systems require high power densities with the ability to sustain high current densities at low temperatures. Conversely, high voltage applications main technology driver is energy density while enhancing cell safety and reducing cost. The focus of this presentation is on the development of active materials well suited for use in lithium-ion cells for low voltage applications. This is achieved by engineering electrode materials with irregular surfaces which result in high interfacial surface areas and short characteristic diffusion lengths. This can be accomplished through a porous secondary particle structure and/or nanoscale primary particle size. A study using X-ray Diffraction (XRD) has been utilized to measure the primary particle size and investigate the plane orientation in the crystalline structure and its correlation to performance. Knowing that Li diffusion is more favorable through specific crystalline planes may assist in material engineering development for better and faster Li-ion transport. These attributes are expected to provide lithium-ion batteries with high power densities. Additionally, this presentation will explain how the above key points were approached and resulted in high powder cathode materials with a Direct Current Resistance (DCR) < 9 ohm at -20°C; a key target set by USABC that enables Li-ion starter battery applications.

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