Flexible Solid Flow Electrodes for High-Energy Scalable Energy Storage

• Published in: Joule Vol. 3; no. 7; pp. 1677 - 1688
• Main Authors: Wang, Zengyue, Tam, Long-Yin Simon, Lu, Yi-Chun
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 17.07.2019
• DOI: 10.1016/j.joule.2019.05.015
• ISSN: 2542-4351

Flow batteries allow independent scaling of power and energy and permit low-cost materials for large-scale energy storage. However, they suffer from low-energy densities or poor scalability when a solid electrode is used in hybrid systems (zinc or lithium metals). Breaking the convention of pumping fluids, we propose and demonstrate a new flow battery invention that transports active material via rotation of flexible electrode belts made from high-energy-density solid electrode materials (flexible solid flow electrode). Using this strategy, we demonstrated a fully scalable aqueous solid-liquid hybrid flow battery using a lithium titanium phosphate (LTP) flexible anode belt coupled with lithium iodide (LiI) catholyte. This strategy of the circulating flexible solid electrode can be readily applied to existing solid-liquid hybrid flow batteries (e.g., Zn-I2, Zn-Br2, Li-I2, Li-polysulfide, etc.) and allows many types of solid electrode materials in a flow battery platform without constraints in solubility or scalability. [Display omitted] •New strategy for scalable energy storage by rolling flexible solid electrode•Robust electrochemical and mechanical performance in aqueous and non-aqueous systems•Extended material choices in flow battery without limits in solubility or scalability Large-scale and long-duration energy storage is required for effective utilization of intermittent solar and wind energy. Flow batteries are ideal for large-scale energy storage owing to independent scaling of power and energy. The energy density of all-vanadium flow batteries is limited by the liquid electrolytes. Emerging solid-liquid hybrid flow batteries (e.g., Zn metal flow battery) use solid active material with improved energy density; however, the hybrid configuration sacrifices scalability. Breaking the convention of pumping fluids, we demonstrate a new flow battery that transports active material via rotation of flexible electrode belts made from high-energy-density solid electrode materials. This strategy can be readily applied to existing hybrid flow batteries (e.g., Zn-I2, Zn-Br2, Li-I2, Li-polysulfide, etc.) and extends flow battery material choices without limits in solubility or scalability. This work describes a new strategy to build high-energy density, fully scalable energy storage devices by using flexible solid electrodes. This work demonstrates a novel method to convert conventional hybrid flow batteries to fully scalable energy storage devices and enables extensive new material chemistries for large-scale energy storage applications.