Optimized, Free-Radical, Large-Batch Synthesis of Microphase-Separated Copolymer Electrolyte

Many Naval capabilities are hamstrung by the need for lighter more powerful batteries, particularly propulsion systems of unmanned surface vessels and underwater vehicles. Lithium-ion batteries with specific energy of 115 to 125 Wh/kg have been demonstrated at the 1 and 100 Ah class size, but significant barriers prevent their safe use as power sources for high-energy, large-scale applications. Due to poor stability and low Li transference number, cell power fades under high charge/discharge rates; sometimes leading to thermal runaway and uncontrolled venting of the cell. Lighter, higher voltage batteries could meet these needs if a stable, highly conductive thin film electrolyte could be manufactured, that reduced the amount of electrolyte and spacer materials. This program will capitalize on the recently reported success of block copolymer based solid-state electrolytes to support both liquid-like conductivy and solid-like mechanical behavior, and develop an economical synthesis approach that is amenable to large-scale production of thin film electrolytes. Synthesis routes starting from inexpensive materials are proposed. Their systematic scale up will be achieved stepwise using increasing larger batch reactors and the electrochemical characteristics of the resulting electrolyte films will be investigated in-house using a standard battery cycler and electrochemical impedance analysis. The proposed program will culminate with the production of safe, solvent-free electrolytes with superior conductivity critical to the development of large, safe, economical rechargeable batteries.