Lithium metal protected by atomic layer deposition metal oxide for high performance anodes. Issue 24 (30th May 2017)

• Record Type: Journal Article
• Authors: Chen, Lin; Connell, Justin G.; Nie, Anmin; Huang, Zhennan; Zavadil, Kevin R.; Klavetter, Kyle C.; Yuan, Yifei; Sharifi-Asl, Soroosh; Shahbazian-Yassar, Reza; Libera, Joseph A.; Mane, Anil U.; Elam, Jeffrey W.
• Is Part Of: Journal of materials chemistry. Volume 5:Issue 24(2017)
• Page Start: 12297
• Page End: 12309
• Publication Date: 2017-05-30
• Subjects: Materials -- Research -- Periodicals; Chemistry, Analytic -- Periodicals; Environmental sciences -- Research -- Periodicals; 543.0284
• DOI: 10.1039/c7ta03116e
• Languages: English
• ISSNs: 2050-7488

Abstract

Abstract : Conformal Al2 O3 coating improves wettability of liquid electrolyte on lithium leading to homogenous electrodeposition, reduced dendrite growth, and improved cyclability. Abstract : Lithium metal is a highly desirable anode material for lithium batteries due to its extremely high theoretical capacity (3860 mA h g −1 ), low potential (−3.04 V versus standard hydrogen electrode), and low density (0.534 g cm −3 ). However, dendrite growth during cycling and low coulombic efficiency, resulting in safety hazards and fast battery fading, are huge barriers to commercialization. Herein, we used atomic layer deposition (ALD) to prepare conformal, ultrathin aluminum oxide coatings on lithium. We investigated the growth mechanism during Al2 O3 ALD on lithium by in situ quartz crystal microbalance and found larger growth than expected during the initial cycles. We also discovered that the ALD Al2 O3 enhances the wettability of the Li surface towards both carbonate and ether electrolytes, leading to uniform and dense SEI formation and reduced electrolyte consumption during battery operation. Scanning electron microscopy verified that the bare Li surfaces become rough and dendritic after electrochemical cycling, whereas the ALD Al2 O3 coated Li surfaces remain smooth and uniform. Analysis of the Li surfaces after cycling using X-ray photoelectron spectroscopy and in situ transmission electron microscopy revealed that the ALD Al2 O3 coating remains intact during electrochemical cycling, and that Li ions diffuse through the coating and deposit on the underlying Li. Coin cell testing demonstrated more than two times longer cycling life for the ALD Al2 O3 protected Li, and a coulombic efficiency as high as ∼98% at a practical current rate of 1 mA cm −2 . More significantly, when the electrolyte volume was reduced from 20 to 5 μL, the stabilizing effect of the ALD coating became even more pronounced and the cycling life was around four times longer. These results indicate that ALD Al2 O3 coatings are a promising strategy to stabilize Li anodes for high performance energy storage devices such as Li–S batteries.