Lithium-ion batteries (LIBs) are the industry standard in commercial electric vehicles (EVs) and occupy a large fraction of the overall EV cost. However, LIBs rely on expensive metals like lithium, cobalt, and nickel, resulting in cost (>7x Li price increase over past year) and geopolitical supply chain bottlenecks which impede EV deployment. This project will develop sodium-ion batteries (SIBs) based on cathodes using low-cost, earth-abundant elements such as sodium, manganese, and iron. This lowers cathode cost by 95% and battery cell cost by over 50% (SIB: $50/ kWh, LFP: $130/ kWh, NCM: $150/ kWh), while still delivering comparable energy densities to current commercial LIB cells (SIB: 200 Wh/kg, LFP: 150 Wh/kg, NCM622: 200 Wh/kg). To ensure cell level cost and energy density metrics are met, cathodes with high energy densities and cycle lifetimes are required. Layered NaMnO2-based SIB cathodes present an enticing next generation cathode material which deliver high energy densities (e.g., P2-Na0.7Mn0.5Fe0.5O2: 190 mAh/g) and eliminate expensive cobalt and nickel-based LIB systems entirely. However, inherent structural issues associated with larger Na-ion (e.g., glide plane phase shifting) as well as chemical instabilities (e.g., manganese dissolution and Jahn Teller distortions) limit long-term stability, restricting application and implementation of low-cost advanced SIB chemistries. To address these challenges, the phase I project will leverage a novel aerosol process developed by the applicant small business to synthesize low-cost, high-performance layered manganese oxide SIB cathode materials. This waste-free, high-yield, and single-step synthesis approach can facilitate the manufacture of materials with precise elemental composition, phase selectivity, and morphological control, which are critical to address the aforementioned problems and meet performance standards. In this Phase I project, will develop a low-cost, high capacity (>195 mAh/g) NaMnO2-based cathode to power a prototype 200 Wh/kg SIB full cell. Leveraging the companys waste-free, high-yield, and single-step synthesis approach, precision doping to control elemental composition, phase selectivity, and morphological control will be deployed to engineer a unique cathode material with distinct surface properties and precise doping in the Mn and Na layers. The resulting high-capacity material will have high stability (>500 cycles) and will be incorporated into a working 200 mAh full cell prototype to be scaled and optimized during Phase II. The end deliverable of the SBIR project will be a low-cost ($50/kWh) high energy density (200 Wh/kg) sodium-ion battery cell capable of powering electric vehicles (short range passenger, 2/3 wheel, buses) as well as low-cost grid storage applications. The developed materials will decouple high-energy rechargeable batteries from their present dependence on expensive elements sourced from vulnerable supply chains, reduce the cost of battery packs by over 50% and ultimately deliver low-cost, earth abundant, and environmentally friendly sodium-ion batteries for electric vehicles.
Keywords: sodium-ion batteries, layered manganese oxide cathodes, earth abundant, low
