Lithium-ion Batteries Based on Aqueous Electrolyte: A New Generation of Sustainable Energy Storage Devices

NEI Corporation proposes to develop a new and sustainable aqueous electrolyte-based lithium-ion (Li-ion) battery system that is capable of delivering high energy density, comparable to state-of-the-art Li-ion batteries. Almost all commercial Li-ion batteries use an organic electrolyte, which is flammable and has been a concern particularly in large format Li-ion batteries. In addition, there are toxicity and other environmental concerns associated with the non-aqueous electrolyte solvents. The principal feature of the proposed effort is the use of a modified high-capacity cathode in conjunction with a functionalized anode that is capable of reaching much higher cell voltages than aqueous systems reported to date. The wider electrochemical potential, combined with the use of a high capacity cathode, will result in an increase in the energy density. Accordingly, the proposed aqueous electrolyte system eliminates the toxicity and flammability associated with organic electrolytes, thereby leading to a safe and environmentally benign system. Also, the proposed approach will eliminate the use of solvents that is so common during electrode fabrication.The target gravimetric and volumetric energy densities for the proposed aqueous electrolyte-based Li­ion system at the pack level are 250Wh/kg and 750 Wh/1, respectively. The Phase 1 effort will entail synthesis and characterization of the modified cathode and anode, along with structural and electrochemical characterization of the cell. In Phase 2, the structure and composition of the electrodematerials will be further optimized, and the ability to fabricate the materials in large volume will be demonstrated. In addition, by working in partnership with battery manufacturers, the newly developed cathode material will be integrated into large format Li-ion batteries. Prototype cell packs will be fabricated and tested by the end of the Phase 2 program.