Temperature-stable NdFeB micromagnets with high-energy density compatible with CMOS back end of line technology

MRS Advances ◽  
2015 ◽  
Vol 1 (3) ◽  
pp. 209-213 ◽  
Author(s):  
Tim Reimer ◽  
Fabian Lofink ◽  
Thomas Lisec ◽  
Claas Thede ◽  
Steffen Chemnitz ◽  
...  
Keyword(s):  
Energy Density ◽  
Solid Body ◽  
Atomic Layer ◽  
High Energy ◽  
High Energy Density ◽  
Stray Field ◽  
Magnetic Powder ◽  
Demagnetizing Field ◽  
Layer Deposition ◽  
Line Technology

ABSTRACTThe performance of a novel type of NdFeB micromagnets fabricated by agglomeration of magnetic powder by atomic layer deposition is investigated. The ALD-bonded micromagnets can withstand standard BEOL (back-end of line) processing and heat treatments at temperatures of up to 400 °C in air and vacuum without any significant impact on the demagnetization curves. By optimized packing density a remanence of 660 mT is realized for the micromagnets. The coercivity µ0Hc = 890 mT remains constant for all samples and corresponds to the powder value.A comparison of the demagnetizing behavior of micromagnets with theory of solid body magnets prove that the influence of particle shape and hollow spaces on demagnetizing field is low. Hence, a similar impact of shape on stray field and forces as for solid body magnets can be assumed when integrating NdFeB ALD-bonded micromagnets in applications.

scholarly journals Enhanced Electrochemical Performance of Supercapacitors via Atomic Layer Deposition of ZnO on the Activated Carbon Electrode Material

Molecules ◽  
2021 ◽  
Vol 26 (14) ◽  
pp. 4188
Author(s):  
Chongrui Wu ◽  
Fuming Zhang ◽  
Xiangshang Xiao ◽  
Junyan Chen ◽  
Junqi Sun ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Atomic Layer Deposition ◽  
Electrode Materials ◽  
Inorganic Compounds ◽  
Atomic Layer ◽  
Cycling Performance ◽  
High Energy ◽  
High Energy Density ◽  
Operating Voltage ◽  
Layer Deposition

Fabricating electrical double-layer capacitors (EDLCs) with high energy density for various applications has been of great interest in recent years. However, activated carbon (AC) electrodes are restricted to a lower operating voltage because they suffer from instability above a threshold potential window. Thus, they are limited in their energy storage. The deposition of inorganic compounds’ atomic layer deposition (ALD) aiming to enhance cycling performance of supercapacitors and battery electrodes can be applied to the AC electrode materials. Here, we report on the investigation of zinc oxide (ZnO) coating strategy in terms of different pulse times of precursors, ALD cycles, and deposition temperatures to ensure high electrical conductivity and capacitance retention without blocking the micropores of the AC electrode. Crystalline ZnO phase with its optimal forming condition is obtained preferably using a longer precursor pulse time. Supercapacitors comprising AC electrodes coated with 20 cycles of ALD ZnO at 70 °C and operated in TEABF4/acetonitrile organic electrolyte show a specific capacitance of 23.13 F g−1 at 5 mA cm−2 and enhanced capacitance retention at 3.2 V, which well exceeds the normal working voltage of a commercial EDLC product (2.7 V). This work delivers an additional feasible approach of using ZnO ALD modification of AC materials, enhancing and promoting stable EDLC cells under high working voltages.

scholarly journals Enhanced Cyclability of Cr8O21 Cathode for PEO-Based All-Solid-State Lithium-Ion Batteries by Atomic Layer Deposition of Al2O3

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5380
Author(s):  
Haichang Zhang ◽  
Zhibin Xu ◽  
Bin Shi ◽  
Fei Ding ◽  
Xingjiang Liu ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Solid State ◽  
Atomic Layer Deposition ◽  
Specific Capacity ◽  
Lithium Ion ◽  
Atomic Layer ◽  
High Energy ◽  
High Energy Density ◽  
Al2o3 Layer ◽  
Layer Deposition

Cr8O21 can be used as the cathode material in all-solid-state batteries with high energy density due to its high reversible specific capacity and high potential plateau. However, the strong oxidation of Cr8O21 leads to poor compatibility with polymer-based solid electrolytes. Herein, to improve the cycle performance of the battery, Al2O3 atomic layer deposition (ALD) coating is applied on Cr8O21 cathodes to modify the interface between the electrode and the electrolyte. X-ray photoelectron spectroscopy, scanning electron microscope, transmission electron microscope, and Fourier transform infrared spectroscopy, etc., are used to estimate the morphology of the ALD coating and the interface reaction mechanism. The electrochemical properties of the Cr8O21 cathodes are investigated. The results show that the uniform and dense Al2O3 layer not only prevents the polyethylene oxide from oxidization but also enhances the lithium-ion transport. The 12-ALD-cycle-coated electrode with approximately 4 nm Al2O3 layer displays the optimal cycling performance, which delivers a high capacity of 260 mAh g−1 for the 125th cycle at 0.1C with a discharge-specific energy of 630 Wh kg−1.

A HIGH ENERGY DENSITY ZINC/OXYGEN BATTERY SYSTEM

1966 ◽  
Author(s):  
S. CHODOSH ◽  
E. KATSOULIS ◽  
M. ROSANSKY
Keyword(s):  
Energy Density ◽  
High Energy ◽  
High Energy Density ◽  
Battery System

Efficient Co-Harvesting of Solar Energy and Low-Grade Heat by Molecular Photoswitches for High Energy Density, Long-Term Stable Solar Thermal Battery

2019 ◽  
Author(s):  
Zhao-Yang Zhang ◽  
Tao LI
Keyword(s):  
Energy Density ◽  
Solar Energy ◽  
High Performance ◽  
High Energy ◽  
Solar Thermal ◽  
High Energy Density ◽  
Low Grade ◽  
Thermal Battery ◽  
Low Grade Heat

Solar energy and ambient heat are two inexhaustible energy sources for addressing the global challenge of energy and sustainability. Solar thermal battery based on molecular switches that can store solar energy and release it as heat has recently attracted great interest, but its development is severely limited by both low energy density and short storage stability. On the other hand, the efficient recovery and upgrading of low-grade heat, especially that of the ambient heat, has been a great challenge. Here we report that solar energy and ambient heat can be simultaneously harvested and stored, which is enabled by room-temperature photochemical crystal-to-liquid transitions of small-molecule photoswitches. The two forms of energy are released together to produce high-temperature heat during the reverse photochemical phase change. This strategy, combined with molecular design, provides high energy density of 320-370 J/g and long-term storage stability (half-life of about 3 months). On this basis, we fabricate high-performance, flexible film devices of solar thermal battery, which can be readily recharged at room temperature with good cycling ability, show fast rate of heat release, and produce high-temperature heat that is >20<sup> o</sup>C higher than the ambient temperature. Our work opens up a new avenue to harvest ambient heat, and demonstrate a feasible strategy to develop high-performance solar thermal battery.

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