The existing baseload nuclear and fossil fuel power generation plants are most efficient and long-lived when operated at constant output while renewable energy generation technologies such as wind and solar suffer from intermittency. There is an unmet need for low-cost efficient energy storage at gigawatt-hour scale capacity to improve the efficiency of the conventional power plants and facilitate the growth and integration of renewable energy. Although pumped hydroelectric storage (PHS) and underground compressed air energy storage (CAES) have the lowest installation costs today (~US$100/kWh), each faces geographical and environmental constraints that may limit further deployment. US Department of Energy grid energy storage report thoroughly evaluated all commercially deployed energy storage technologies and concluded that rechargeable batteries are technically viable energy storage solutions to provide most grid energy storage services. Flow batteries possess an attractive architecture for grid-scale storage due to their ability to decouple stored energy (the tanks) from power (the stack), inherent scalability, and potentially low cost. Conventional flow batteries store aqueous redox active solution in external tanks and pump the solution through an ion-exchange/electron-extraction power stack to store or deliver electricity. The “anolyte” and “catholyte” refer to fluids with solubilized active materials and correspond to “anode” and “cathode” in solid-phase active materials. we herein demonstrate and analyze a new Na-S flow battery utilizing molten sodium metal and flowable sulfur-based suspension as electrodes. Unlike the conventional flow battery and the high-temperature Na-S battery, the proposed flow battery system decouples the energy and power thermal management by operating at different temperatures for the storage tank (near room temperature) and the power stack (100-150 °C). This presentation will break ground for fundamental research on electrochemically active semi-solid Na-S suspension at intermediate temperature to enable optimal flow battery design. First, we will focus on the polysulfide reaction species and electrode process of semi-solid Na-S suspension catholyte to understand reaction pathway of Na-S cell at intermediate temperature. Second, we will focus on the physical and rheological properties of the Na-S semi-solid suspension to understand the reaction kinetics and improve the design of the flow battery power stack.

Sodium-sulfur flow battery for low-cost electrical storage

255th National Meeting (2018)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.