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 ◽  
...  

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.

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5380
Author(s):  
Haichang Zhang ◽  
Zhibin Xu ◽  
Bin Shi ◽  
Fei Ding ◽  
Xingjiang Liu ◽  
...  

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.


2020 ◽  
Vol 299 ◽  
pp. 1058-1063
Author(s):  
Denis Nazarov ◽  
Ilya Mitrofanov ◽  
Maxim Yu. Maximov

Tin oxide is the most promising material for thin film anodes of Li-ion batteries due to its cycling performance and high theoretical capacity. It is assumed that lithium-tin oxide can demonstrate even higher performance. Lithium-silicon-tin oxide nanofilms were prepared by atomic layer deposition (ALD), using the lithium bis (trimethylsilyl) amide (LiHMDS), tetraethyltin (TET) as a metal containing reagents and ozone or water or oxygen plasma as counter-reactants. Monocrystalline silicon (100) and stainless steel (316SS) were used as supports. The thicknesses of the nanofilms were measured by spectral ellipsometry (SE) and scanning electron microscopy (SEM). It was found that oxygen plasma is the most optimal ALD counter-reactant. The composition and structure were studied by Time-of-Flight Secondary Ion Mass Spectroscopy (ToF-SIMS), X-ray Photoelectron Spectroscopy (XPS) and X-ray diffraction (XRD). The nanofilms contain silicon as impurity, whose source is the ALD precursor (LiHMDS). The nanofilms deposited on stainless steel have shown the high Coulombic efficiency (99.1-99.8%) and cycling performance at a relatively high voltage (0.01 to 2.0V).


RSC Advances ◽  
2016 ◽  
Vol 6 (103) ◽  
pp. 100841-100848 ◽  
Author(s):  
Gaole Dai ◽  
Hongjuan Du ◽  
ShanShan Wang ◽  
Jiali Cao ◽  
Min Yu ◽  
...  

Thickness-controlled TiO2 shell and enhanced cycling performance.


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