Ionic Liquid Enabled High-Energy Li-ion Battery

While rechargeable lithium-ion batteries have dominated the portable electronics market for nearly a decade, they have failed to gain widespread commercial success in high power and high capacity applications. Despite a slow rate of improvement in battery cost and capacity each year, demand for a battery providing 400 Wh/kg, or double the specific energy of current state-of-the-art lithium-ion batteries, is growing. Reaching the DOE VTOs goal will require breakthroughs in next-generation electrode materials. Incorporating higher energy-density active materials is a necessity. Most research aimed towards enabling next-generation electrode materials, both in academia and industry, focuses on material modification. For example, developing nano-architectured silicon composites is a popular method for enabling the highly energy-dense silicon anode. Such electrodes are complex, requiring advanced processing methods, and therefore face a major barrier in terms of economic feasibility to realize market penetration. Conversely, the proposed venture will work to enable attractive electrode materials using a new class of electrolyte: room temperature ionic liquids. This work proposes to develop a novel lithium-ion battery comprised of the previously developed Si anode, an imide-based room temperature ionic liquid electrolyte, and a highly energy-dense Li-Mn- rich cathode. Preliminary research on the Li-Mn-rich room temperature ionic liquid system has shown stable cycling and significant hindrance of the voltage fade mechanism that plagues high voltage Li-Mn-rich electrode materials. If successful, it is anticipated that the proposed technology will result in a full-cell having a specific energy approaching 400 Wh/kg with the added benefit of a non-flammable room temperature ionic liquid electrolyte. Of high significance is the compatibility of such a system with the conventional battery-manufacturing infrastructure; the proposed system serves as a true drop-in replacement for those materials currently utilized. In order to demonstrate the proposed Si-anode/room temperature ionic liquid/Li- Mn-rich Li-ion cell as the next-generation replacement for state-of-the-art technology, as well as to position this venture for future investment, the proposed Phase I objectives are designed to enable reliable, long-term cycling of the Li-Mn-rich cathode i.e., hinder phase transition, minimize voltage fade, and prevent capacity degradation). At the end of the proposed SBIR work plan, this project will provide a 200 mAh Si/Li-Mn-rich pouch-cell which will demonstrate the high commercial potential of its key technologies. While BMW, Nissan, and GM now offer more affordable models including the i3, Leaf, and Chevy Bolt, consumers are concerned about driving range, charge time, and overall convenience with the less expensive EV options. If successful in enabling the proposed technology, this work could offer the public an opportunity to own an affordable, safe, environmentally conscious vehicle. This opportunity is not limited to the automotive segment. The proposed technology fits well with in the performance requirements of the portable electronics industry. Thus, the proposed technology will be of interest to a number of industries looking to grow by developing smaller, more powerful devices.