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Abstract Rechargeable alkali metal anodes hold the promise to significantly increase the energy density of current battery technologies. But they are plagued by dendritic growths and solid‐electrolyte interphase (SEI) layers that undermine the battery safety and cycle life. Here, a non‐porous ingot‐type sodium (Na) metal growth with self‐modulated shiny‐smooth interfaces is reported for the first time. The Na metal anode can be cycled reversibly, without forming whiskers, mosses, gas bubbles, or disconnected metal particles that are usually observed in other studies. The ideal interfacial stability confirmed in the microcapillary cells is the key to enable anode‐free Na metal full cells with a capacity retention rate of 99.93% per cycle, superior to available anode‐free Na and Li batteries using liquid electrolytes. Contradictory to the common beliefs established around alkali metal anodes, there is no repeated SEI formation on or within the sodium anode, supported by the X‐ray photoelectron spectroscopy elemental depth profile analyses, electrochemical impedance spectroscopy diagnosis, and microscopic imaging.
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Review of Emerging Concepts in SEI Analysis and Artificial SEI Membranes for Lithium, Sodium, and Potassium Metal Battery Anodes
Abstract Anodes for lithium metal batteries, sodium metal batteries, and potassium metal batteries are susceptible to failure due to dendrite growth. This review details the structure–chemistry–performance relations in membranes that stabilize the anodes’ solid electrolyte interphase (SEI), allowing for stable electrochemical plating/stripping. Case studies involving Li, Na, and K are presented to illustrate key concepts. “Classical” versus “modern” understandings of the SEI are described, with an emphasis on the new structural insights obtained through novel analytical techniques, including in situ liquid‐secondary ion mass spectroscopy, titration gas chromatography, and tip‐enhanced Raman spectroscopy. This Review highlights diverse approaches for increasing SEI stability, either by inserting a secondary layer between the native SEI and the separator, or by combining the membrane with a native SEI to form a hybrid composite. Exciting and nonintuitive findings are discussed, such as that the metal anode roughness profoundly affects the SEI structure and stability, or that organic artificial SEI‐layers may be more effective than the native inorganic–organic SEIs. Emerging multifunctional architectures are presented, which serve a dual role as metal hosts and metal surface protection layers. Throughout the Review, fruitful future research directions and the critical areas where there is incomplete understanding are discussed.
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- Award ID(s):
- 1911905
- PAR ID:
- 10455893
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Energy Materials
- Volume:
- 10
- Issue:
- 43
- ISSN:
- 1614-6832
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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