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 t...

Next-Generation Lithium Metal Anode Engineering via Atomic Layer Deposition

Their Applications Kesong Liu,†,∥ Moyuan Cao,† Akira Fujishima, and Lei Jiang*,†,‡ †Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry and Environment, Beihang University, Beijing 100191, PR China ‡Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, PR China Research Institute for Science and Technology, Photocatalysis International Research Center, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku-ku, Tokyo 162-8601, Japan Institute for Superconducting and Electronic Materials, University of Wollongong, Innovation Campus, Squires Way, North Wollongong, NSW 2500, Australia

Bio-Inspired Titanium Dioxide Materials with Special Wettability and Their Applications

For the successful commercialization of organic–inorganic halide perovskite solar cells, it is necessary to ensure their stability in addition to high efficiency. In this study, the degradation mechanism of organic–inorganic halide structures in humidity was investigated computationally. Owing to the high polarity of water molecules, the unprotected organic–inorganic structure will inevitably decompose in a humid environment. To improve the ambient stability of the organic–inorganic perovskite solar cells, we introduced an interface modification method using ultrathin compact aluminum oxide (Al2O3) layers deposited by atomic layer deposition (ALD). The experimental results showed the ambient stability of the organic–inorganic perovskite solar cell with an ultrathin compact Al2O3 layer was greatly improved without a significant reduction in efficiency.

Improvement of the humidity stability of organic–inorganic perovskite solar cells using ultrathin Al2O3 layers prepared by atomic layer deposition

Ultrathin Surface Coating Enables the Stable Sodium Metal Anode

Producing hydrogen through solar water splitting requires the coverage of large land areas. Abundant metal-based molecular catalysts offer scalability, but only if they match noble metal activities. We report on a highly active p-GaInP2 photocathode protected through a 35-nm TiO2 layer functionalized by a cobaloxime molecular catalyst (GaInP2–TiO2–cobaloxime). This photoelectrode mediates H2 production with a current density of ∼9 mA cm−2 at a potential of 0 V versus RHE under 1-sun illumination at pH 13. The calculated turnover number for the catalyst during a 20-h period is 139,000, with an average turnover frequency of 1.9 s−1. Bare GaInP2 shows a rapid current decay, whereas the GaInP2–TiO2–cobaloxime electrode shows ≤5% loss over 20 min, comparable to a GaInP2–TiO2–Pt catalyst particle-modified interface. The activity and corrosion resistance of the GaInP2–TiO2–cobaloxime photocathode in basic solution is made possible by an atomic layer-deposited TiO2 and an attached cobaloxime catalyst. Producing hydrogen via solar water splitting with metal-based molecular catalysts offers scalability. An active p-GaInP2 photocathode stabilized by a TiO2 layer functionalized by a cobaloxime molecular catalyst is now reported for water reduction.

Water reduction by a p-GaInP2 photoelectrode stabilized by an amorphous TiO2 coating and a molecular cobalt catalyst.

Al2O3 and TiO2 atomic layer deposition (ALD) were employed to develop an ultrathin barrier film on copper to prevent water corrosion. The strategy was to utilize Al2O3 ALD as a pinhole-free barrier and to protect the Al2O3 ALD using TiO2 ALD. An initial set of experiments was performed at 177 °C to establish that Al2O3 ALD could nucleate on copper and produce a high-quality Al2O3 film. In situ quartz crystal microbalance (QCM) measurements verified that Al2O3 ALD nucleated and grew efficiently on copper-plated quartz crystals at 177 °C using trimethylaluminum (TMA) and water as the reactants. An electroplating technique also established that the Al2O3 ALD films had a low defect density. A second set of experiments was performed for ALD at 120 °C to study the ability of ALD films to prevent copper corrosion. These experiments revealed that an Al2O3 ALD film alone was insufficient to prevent copper corrosion because of the dissolution of the Al2O3 film in water. Subsequently, TiO2 ALD was explored on copper...

Al2O3 and TiO2 atomic layer deposition on copper for water corrosion resistance.

Joule-Thomson micro cryogenic coolers (MCCs) are a preferred approach for small and low power cryocoolers. With
the same heat lift, MCC's power input can be only 1/10 of a thermoelectric cooler's input, and MCC's size can be only
1/10 of a Stirling cooler's size. With futuristic planar MCC and with high frequency MEMS compressors to be
developed, its size can be reduced another order of magnitude. Such "invisible" cryocoolers may revolutionize future
IR imaging systems. We will review our studies on the feasibility of MCC with an emphasis on: 1) high thermal
isolation levels reaching 89,000 K/W; 2) custom-designed gas mixtures with refrigeration capabilities increased by 10X
and pressure ratio reduced to only 4:1; 3) compressors with low pressure ratios; and 4) excellent scalability for further
size reduction.

Micro cryogenic coolers for IR imaging

Joule-Thompson (J-T) based micro cryogenic coolers (MCCs) are attractive because they can provide the cryogenic temperatures needed for small electronic devices while having a low cost and small volumetric footprint. A compressor is a major part of a cryogenic system, but so far J-T based MCCs have not used miniature or micro scale compressors. This work demonstrates a J-T based MCC coupled with a miniature compressor for cooling to 200 K, using a custom hydrocarbon mixture as refrigerant. The compressor is formed by coupling a miniature piston oscillator built for Stirling coolers with a micromachined check valve assembly. The MCC is formed by glass fibers within a capillary forming a counter flow heat exchanger, and a silicon and glass chip forming a J-T valve. Minimum temperatures of 166 K have been observed in transient, and stable temperatures of 200 ±1 K have been observed for >1 hour. Some insight is given into the unstable performance in terms of intermittent liquid accumulation. The coefficient of performance is analyzed for the system, and it is found that most of the inefficiencies arise at the compressor.Copyright © 2011 by ASME

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Jill Cooper

Papers

Al2O3 and TiO2 atomic layer deposition on copper for water corrosion resistance.

Micro cryogenic coolers for IR imaging

Demonstration of an Integrated Micro Cryogenic Cooler and Miniature Compressor for Cooling to 200 K

Performance Analysis of an Integrated Micro Cryogenic Cooler and Miniature Compressor for Cooling to 200 K