Visualizing the Interfacial Chemistry in Multivalent Metal Anodes by Transmission Electron Microscopy

Abstract

Multivalent metal batteries (MMBs) have been considered potentially high‐energy and low‐cost alternatives to commercial Li‐ion batteries, thus attracting tremendous research interest for energy‐storage applications. However, the plating and stripping of multivalent metals (i.e., Zn, Ca, Mg) suffer from low Coulombic efficiencies and short cycle life, which are largely rooted in the unstable solid electrolyte interphase. Apart from exploring new electrolytes or artificial layers for robust interphases, fundamental works on deciphering interfacial chemistry have also been conducted. This work is dedicated to summarizing the state‐of‐the‐art advances in understanding the interphases for multivalent metal anodes revealed by transmission electron microscopy (TEM) methods. Operando and cryogenic TEM with high spatial and temporal resolutions realize the dynamic visualization of the vulnerable chemical structures in interphase layers. Following a scrutinization of the interphases on different metal anodes, we elucidate their features for appealing multivalent metal anodes. Finally, perspectives are proposed for the remaining issues on analyzing and regulating interphases for practical MMBs.

Deciphering Anion‐Modulated Solvation Structure for Calcium Intercalation into Graphite for Ca‐Ion Batteries

“…Together with the merits of high crustal abundance (4.1 wt %) and dendrite-free deposition of Ca metal, CIB is regarded as a promising next-generation energy storage device. [6][7][8][9] However, the development of CIBs is still at a nascent stage, primarily hindered by the lack of suitable electrode materials and compatible electrolytes.…”

“…The minimal polarization strength of Ca 2+ (Ca 2+ : 10.4, Mg 2+ : 14.7, Al 3+ : 24, Zn 2+ : 16) further suggests the relatively faster Ca ion mobility in the host materials. Together with the merits of high crustal abundance (4.1 wt %) and dendrite‐free deposition of Ca metal, CIB is regarded as a promising next‐generation energy storage device [6–9] . However, the development of CIBs is still at a nascent stage, primarily hindered by the lack of suitable electrode materials and compatible electrolytes.…”