Publication source
ACS Applied Energy Materials
Volume 2, Issue 3, 25 March 2019, Pages 1774-1783
Link to article
Authors
Moitzheim S., Balder J.E., Ritasalo R., Ek S., Poodt P., Unnikrishnan S., De Gendt S., Vereecken P.M.
Abstract
Three-dimensional (3D) thin-film solid-state batteries are an interesting concept for microstorage, promising high footprint capacity, fast charging, safety, and long lifetime. However, to realize their commercialization, several challenges still need to be overcome. In this work, we focus on two issues: the conformal coating and the high throughput deposition of thin-film layers. First, to facilitate conformal deposition, a design based on 3D micropillars is chosen. Although such a design has been suggested in the past, we calculate for the first time what (footprint) capacities can be expected when using fully optimized pillar geometries while taking practical manufacturability into consideration. Next, spatial atomic layer deposition (S-ALD) is investigated as a scalable and conformal deposition technique. As proof-of-concept, 100 nm Cl-doped am-TiO2 thin-film electrodes are deposited by S-ALD on TiN-coated silicon micropillars. The influence of deposition parameters (i.e., exposure time and temperature) on the conformality and uniformity across the micropillar substrate is investigated. The results are discussed in terms of precursor diffusion and depletion, which is supported by an analytical model developed for our micropillar array. Furthermore, the Li-ion insertion properties of 3D electrodes fabricated by S-ALD and conventional ALD are compared. This research highlights the challenges and promises of 3D microbatteries and guides future S-ALD development to enable conformal and high-throughput thin-film deposition.
Copyright © 2019 American Chemical Society.
Read the whole article published in the American Chemical Society here.
Funding text
S.M. gratefully acknowledges the support of a Ph.D. stipend from the Agency for Innovation by Science and Technology in Flanders (IWT).
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