Sunday, May 24, 2015

Next-Generation Lithium Metal Anode Engineering by Atomic Layer Deposition

Researchers at University of Maryland demonstrate Al2O3 ALD of protection layers directly on Li metal that protect the Li surface from corrosion due to atmosphere, sulfur, and electrolyte exposure. Lithium metal is considered to be the most promising anode for next-generation batteries due to its high energy density of 3840 mAh g–1. Major obstacles for lithium metal anodes is that the Li surface is highly reactive which can lead to reactions with the solvents and the electrolyte and contamination, reducing the performance of batteries employing Li metal anodes. 

Next-Generation Lithium Metal Anode Engineering via Atomic Layer Deposition 

Alexander C. Kozen, Chuan-Fu Lin, Alexander J. Pearse, Marshall A. Schroeder, Xiaogang Han, Liangbing Hu, Sang-Bok Lee, Gary W. Rubloff, and Malachi Noked





Lithium metal is considered to be the most promising anode for next-generation batteries due to its high energy density of 3840 mAh g–1. However, the extreme reactivity of the Li surface can induce parasitic reactions with solvents, contamination, and shuttled active species in the electrolyte, reducing the performance of batteries employing Li metal anodes. One promising solution to this issue is application of thin chemical protection layers to the Li metal surface. Using a custom-made ultrahigh vacuum integrated deposition and characterization system, we demonstrate atomic layer deposition (ALD) of protection layers directly on Li metal with exquisite thickness control. We demonstrate as a proof-of-concept that a 14 nm thick ALD Al2O3 layer can protect the Li surface from corrosion due to atmosphere, sulfur, and electrolyte exposure. Using Li–S battery cells as a test system, we demonstrate an improved capacity retention using ALD-protected anodes over cells assembled with bare Li metal anodes for up to 100 cycles.