Novel Cobalt-Rich Composite (CRC) Cathode and Siox Anodes for High-Energy Li-Ion Batteries

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The increasing sophistication and functionality of mobile devices coupled with the human dependence for the devices leads to a strong demand for high performance batteries. Over the years, improvements in battery performance have taken place with minor enhancements resulting from improvement in cell design such as increasing the active material content, increasing the electrode density and reducing the weight and thickness of the inactive cell components. Further improvements by cell optimization are quickly reaching their limits creating a shift in focus to new active electrode material that are expected to result in the next leap in cell performance. In this work, Cobalt-Rich Composite (CRC) cathodes have been developed by modifying standard low voltage LiCoO2 (LCO) and stabilizing the structure by forming high Nickel and Manganese containing composites. The resulting CRC cathode shows surprisingly stable high voltage performance compared to LCO as shown in Figure 1. Traditionally the structure of LCO cathode falls apart at high charge voltages (>4.35V) when >0.5 moles of Li are extracted from the structure. The CRC cathode enables high electrode active content (>97%) and density (>4.0g/cc), high average voltage and high specific capacity required for high-energy cells. To complement the CRC cathode, a high capacity SiOx-based anode electrode has been developed. Current lithium ion cells continue to use graphite as the anode of choice. Si-based anodes have been widely studied as a possible replacement to graphite due to their high specific capacity (~4000mAh/g). Unfortunately Si-based materials suffer from large volume expansion resulting in pulverization and poor cycle life. However, by precise engineering the anode electrode formulation, binder and active material, high capacity SiOx-based anode electrodes with high percent active content (>80%) have been developed and shown to cycle well. Figure 2 shows 1Ah pouch cell data from cells integrating CRC cathode and SiOx anode, showing high specific energy of 285Wh/Kg and cycle life of ~450 cycles before reaching 80% capacity retention at C/5 rate. Swelling and abuse testing of the cells meet consumer electronics specifications and results will be presented. Figure 3 shows that by engineering the cell design and increasing the cell footprint, 10Ah capacity pouch cells integrating CRC cathode and SiOx anode with specific energy of ~350Wh/Kg have been made enabling automotive and drone applications. This presentation will also cover remaining challenges associated with CRC cathode and SiOx anode with respect to synthesis, performance and cell manufacturing to bring these materials and cell technology from prototypes to large-scale manufacturing. Figure 1