SEI Stabilization of Si anodes via Conducting Polymer Encapsulation

The integration of silicon anodes, with their high theoretical specific capacity (4200 mAh/g vs. 372 mAh/g for the conventional graphite anode), into Li-ion cells and subsequent battery packs can significantly increase their energy density, which will assist in extending the range of electric vehicles. However, they suffer from low rapid capacity fade (low cycle-life) due to physical (mechanical fracturing) and chemical (Solid Electrolyte Interface [SEI] layer overgrowth) degradation during repeated cycling. To increase the cycle-life of Si as an anode in Li-ion batteries, we propose to develop a novel Si anode with an advanced artificial SEI layer to prevent the physical and chemical degradation experienced during battery charge and discharge cycles. In Phase I, Triton Systems Inc. will explore a family of Si anode materials with electron and Li- ion conducting properties. Once characterized, the advanced Si material will be deposited on a Cu current collector to be used as an anode material in full-cell battery coin-cell prototypes that are greater than 200mAh in size. Battery prototypes will be tested in accordance with applicable test procedures as published by the Department of Energy (DOE) and the U.S Advanced Battery Consortium (USABC) found at www.uscar.org/guest/article_view.php?articles_id=86.