In situ electrochemical impedance spectroscopy monitoring of the high-temperature double-discharge mechanism of Nb12WO33 cathode material for long-life thermal batteries

作者：Lingbang Qiu, Jiangmin Jiang, Libo Wang, Lang Bai, Fei Zhou, Gaoyu Zhou, Quanchao Zhuang, Yanhua Cui · 发表于：Acta Physico-Chimica Sinica · 年份：2024 · DOI：10.1016/j.actphy.2024.100040 · 被引用次数：12 · 研究领域：Molten salt chemistry and electrochemical processes、Advancements in Battery Materials、Advancements in Solid Oxide Fuel Cells

As a primary energy storage device, the thermal battery offers advantages such as high specific energy and high-power density. However, developing new cathode materials with high specific capacity and thermal stability to meet the evolving needs of thermal batteries remains a significant challenge. Moreover, the high discharge temperatures of thermal batteries and the instability of the molten salt electrolyte system complicate the electrochemical in situ characterization of these systems. In this context, in situ electrochemical impedance spectroscopy (EIS) has become widely employed in electrochemistry and represents a promising technique for in situ monitoring of thermal battery systems. Niobium-tungsten oxides, which possess a Wadsley-Roth crystal shear structure, exhibit excellent rate capability and cyclic stability as anode materials for lithium-ion batteries. Among them, Nb 12 WO 33 demonstrates remarkable lithium storage performance due to its unique 3D tunneling structure, which provides rapid de-intercalation channels for Li + ions. Given its excellent thermal and electrochemical stability, this study proposes the use of Nb 12 WO 33 as a cathode material for thermal batteries for the first time. Electrochemical impedance spectroscopy (EIS) at room temperature was employed to investigate the variations in the material's internal electronic conductivity impedance. The EIS Nyquist plots of the Nb 12 WO 33 electrode reveal a distinctive phenomenon of three semicircles ...