2, Research Institute of Industrial Science & Technology, Pohang, , Korea (the Republic of)
Stationary energy storage systems (ESS) are considered a key component for Grid-Modernization, as they buffer the intermittent generation of renewable energy resources while improving the flexibility and reliability of the electric power grid. Rechargeable sodium (Na) based batteries provide great promise for ESS applications by utilizing earth abundant sodium resources which are much less susceptible to supply chain risks than lithium based systems. While several types of sodium batteries have been reported over recent years, sodium-metal halide (Na-MH) batteries are a compelling candidate for ESS application due to their ability to operate at lower temperatures and their inherent safety over traditional sodium-sulfur technologies. Research at PNNL has been primary focused on developing advanced Na-MH battery technologies that require operating temperatures less than 200°C (from > 300°C for traditional systems) to enable low-cost manufacturing process to be employed. Critical to this objective is the development of high performance, low-temperature cathode material. It was found that lowering operating temperature helps suppress degradation and retains higher energy density while providing opportunities to deploy conventional high temperature polymers as sealing materials. This presentation will detail the materials and cell assembly advancements developed to enable lower temperature Na-MH battery technology.