The broader impact/commercial potential of this Small Business Innovation Research (SBIR) project is the commercialization of an aqueous lithium and zinc ion battery that is a replacement for lead-acid and lithium-ion batteries in stationary energy storage applications.This battery has a nonflammable, environmentally-friendly, water-based electrolyte and does not utilize cobalt or nickel, reducing reliance on critical materials and helping to diversify battery material supply chains.The battery chemistry combines the high safety and low cost associated with zinc-based batteries with the long life of lithium-ion batteries.This aqueous battery may help to advance the adoption of beneficial energy technologies such as intermittent renewables and electric vehicles.The battery utilizes zinc that can be sourced domestically and does not introduce a dependency on foreign sources, promoting both national security and the creation of US-based jobs.The battery is also fully recyclable using existing methods.This SBIR Phase II project proposes to develop the aqueous lithium and zinc ion battery technology by focusing on optimization of individual battery components to improve cycle life and power as well as scale up from pouch cells to larger-format prismatic cells.The research will include refining the intercalation electrode design to increase capacity retention during long life cycling, developing the zinc electrode design to suppress zinc dendrite growth, improving separator functionality to maintain high-rate capabilities and increase cycle life, and developing an electrolyte designed to stabilize zinc while also allowing for faster reactivity with the zinc and lithium ions.Larger format cells with optimized components will be built and tested to evaluate scaled real-world performance metrics compared to Lead-acid and lithium-ion batteries traditionally used in stationary energy storage applications.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.