Interface chemistry for sodium metal anodes/batteries: a review

Abstract

Sodium metal batteries (SMBs), benefiting from their low cost and high energy densities, have drawn considerable interest as large-scale energy storage devices. However, uncontrollable dendritic formation of sodium metal anodes (SMAs) caused by inhomogeneous deposition of Na+ severely decreases the Coulombic efficiency, leads to short cycling life, and poses potential safety hazards, dragging SMBs out of practical applications. Electrolytes are attracting massive attention for not only providing ion transport channels but also exhibiting vital effects on interfacial compatibility and dendrite growth. In fact, the as-formed solid electrolyte interphase (SEI) has a great influence on the deposition and stripping process of SMAs. Moreover, Na plating process is accompanied by the generation of SEI, in which the electrolyte plays a vital role. Nevertheless, until now, the interaction among electrolyte-SEI-sodium dendrite has rarely been summarized. Herein, a fundamental understanding of sodium dendrite is concluded and the influence of the electrolyte and interface on Na+ deposition is emphasized. Furthermore, the outlook for constructing dendrite-inhibited SMAs is suggested.

Intelligent Monitoring for Safety‐Enhanced Lithium‐Ion/Sodium‐Ion Batteries

“…But the safety as the central problem of LIBs and SIBs is concerned extremely to a higher level. [ 3–10 ]…”

A Series of Hybrid Multifunctional Interfaces as Artificial SEI Layer for Realizing Dendrite Free, and Long‐Life Sodium Metal Anodes

“…[16] Several strategies have been adapted over Na metal anode to achieve a smooth and dendrite free Na deposition/stripping : i) Engineering the electrolytes with new formulations and addition of additives to reduces the reactivity of Na metal with electrolyte, and to improve the SEI layer stability ii) nanostructured current collectors and 3D host materials to minimize the local current density, and homogenize the Na-ion flux to achieve reduced vol-ume expansion and dendrite free deposition during cycling; iii) constructing a interface layer or a Na-ion conductive "artificial" SEI layer with good mechanical strength to regulate the facile Na-ion transport to promote the uniform Na deposition. [17,18] In general, constructing a interface layer over Na metal surface is an efficient strategy to overcome the issues in Na metal anode as the interface layer could act as artificial barriers to lower electrochemical reactivity of Na metal, thus effectively suppressing the occurrence of side reactions. The SEI layer is still formed over the artificial SEI layer during initial cycling, but the SEI formation is much less reactive due to the presence of artificial layer over the metal anodes.…”

Highly Ion-Conducting Protective Layers with Nanomicro Engineering for High-Performance Lithium Metal Anodes

“…Over the last two decades, considerable strategies have been presented to overcome these crucial issues for improving the performance of LMBs. These strategies include the development of electrolyte additives, − design of stable artificial SEI layers, − modification of separators, − introduction of three-dimensional (3D) current collectors, − and construction of solid-state electrolytes. − Among these approaches, a reliable SEI is essential for achieving stable LMBs. The spontaneously formed SEI is brittle and heterogeneous, which leads to ongoing electrolyte consumption and localized deposition of Li, resulting in the formation of Li dendrites.…”