G. Li, J.M. Weller, H.H. Han, E. Polikarpov, D.M. Reed, V.L. Sprenkle
Pacific Northwest National Lab,
United States
Keywords: energy storage, Na battery, solid-state electrolyte
Summary:
As the global deployment of renewable energy resources like wind and solar power expands, addressing the challenge of intermittency in energy generation becomes increasingly crucial. Extensive research has been driven by the need for cost-effective energy storage solutions to manage the intermittency of these resources across various storage durations. Among the proposed technologies, battery energy storage stands out as a geography-agnostic and decentralized solution, offering more efficient utilization of renewable power resources. While lithium-ion batteries (LIBs) have dominated the grid-scale battery storage and electric vehicle markets, concerns about the relatively low abundance of raw materials such as lithium (Li) or cobalt (Co) pose challenges for the continued scaling of LIBs for grid applications. Additionally, LIB-based battery storage systems typically have discharge durations of around 4 hours, suitable for short-term grid services but not ideal for long-duration energy storage (LDES) exceeding 10 hours. This limitation has renewed interest in elevated temperature molten sodium (Na) batteries, including sodium-sulfur (Na-S) and sodium metal-halide (Na-MH) batteries. Molten Na batteries offer the advantage of utilizing more abundant and lower-cost raw materials, addressing concerns related to material supply chains. A significant focus in molten Na battery research is the reduction of high operating temperatures (250-350 C) to levels closer to the melting point of Na (~100 C). This approach aims to maintain the benefits of a liquid metal anode while minimizing the battery thermal management and enabling the application of more cost-effective large scale cell manufacturing processes. Lower temperatures also contribute to improvements in cell performance, including long cycle life and higher capacity utilization. This presentation will showcase the latest advancements in Pacific Northwest National Laboratory's (PNNL) Na battery technologies, with a particular emphasis on their applicability to long-duration energy storage applications.