Membrane‐Free Alkali Metal‐Iodide Battery with a Molten Salt

Abstract

in the range of 200-4000 mAh g À1 , and their highly negative redox potential below À2.5 V versus standard hydrogen electrode (SHE) can lead to a high cell operating voltage. These characteristics can enable high specific energies, which are generally given in the unit Wh kg À1 for expressing the energy-storage performance per mass of active materials or the system's total mass. However, the development of rechargeable batteries with alkali and alkaline earth metals has been extremely challenging due to the formation of dendrites, causing safety, stability, and efficiency issues. [1,4,5] As a solution to dendrite formation, solid-state electrolytes can be used as an alternative to conventional electrolytes dissolved in aqueous or organic solvents. However, according to recent studies, [5][6][7][8] dendrites can still penetrate the solid-state electrolytes, and the solid-solid interface of such energy-storage systems may cause other issues such as limited electrochemical stability window and physical contact loss between the electrolyte and the metal.Another effective approach for handling the dendrite formation is to employ liquid metal anodes. [9][10][11][12][13][14] At temperatures above 25 °C, the redox reactions of alkali and alkaline earth metals can be utilized in a molten state either in its pure metal form [13,15] or

Reusable Cell Design for High-Temperature (600 °C) Liquid Metal Battery Cycling

“…These two cell designs are based on the previously developed simple cell used for the membrane-free alkali metal-iodide battery (Conductive Cell Body design; Fig. 1c) by Lee et al 40 Further experiments with this early design revealed unstable electrical contact between the glassy carbon crucible and the cell body. In this configuration, the electrical contact relies solely on gravity, making it necessary for both interfaces to be perfectly flat and clean.…”

“…W-HV10S-CE-NI24) were successfully used in Ref. 40. However, for the Na-Zn cell described in this paper the aforementioned feedthroughs are not suitable.…”

“…with tube fittings, are readily available at a low cost. Consequently, we devised the initial design for a membrane-free alkali metal-iodide battery cycling, 40 as shown in Fig. 1c.…”