Uneven deposition on the Al electrode under tension strain

Structural deformation and dendrite formation, which would impact the electrochemical processes of rechargeable metal batteries, are usually observed in the high-energy density metal electrodes. Herein,we design an in-situ optical mechano-electrochemical system to study Al deposition on the Al electrode in non-aqueous Al batteries under non-uniform strain. Inhomogeneous distribution of applied strain is realized by creating an oval hole in the Al electrode. The results of the in-situ experiments suggest that the dense Al deposition, which is related to the evolution of surface morphology and increasing reactive sites, is achieved in the regions of stress concentration. The evolution of surface morphology is monitored by the in-situ tension experiments using scanning electron microscope and atomic force microscope.Besides, a qualitative mathematical model is employed to analyze the changes of the local reaction rate owing to the changed surface morphology and the cracks of oxide film under tensile stress. The results are useful to understand the Al deposition when the mechanical force is applied to the metal electrode.

Influence of annealing temperature on passivation performance of thermal atomic layer deposition Al_2O_3 films

Chemical and field-effect passivation of atomic layer deposition （ALD） Al2O3 films are investigated, mainly by corona charging measurement. The interface structure and material properties are characterized by transmission electron microscopy （TEM） and X-ray photoelectron spectroscopy （XPS）, respectively. Passivation performance is improved remarkably by annealing at temperatures of 450 ℃ and 500 ℃, while the improvement is quite weak at 600 ℃, which can be attributed to the poor quality of chemical passivation. An increase of fixed negative charge density in the films during annealing can be explained by the Al2O3/Si interface structural change. The Al–OH groups play an important role in chemical passivation, and the Al–OH concentration in an as-deposited film subsequently determines the passivation quality of that film when it is annealed, to a certain degree.

Formation of Ultrafine Metal Particles and Metal Oxide Precursor on Anodized Al by Electrolysis Deposition

Nickel was deposited by ac electrolysis deposition in the pores of the porous oxide film of Al produced by anodizing in phosphoric acid. Ultrafine rod-shaped Ni particles were formed in the pores. At the same time a film of Ni oxide precursor was developed on the surface of the porous oxide film. The Ni particles and the Ni oxide precursor were examined by SEM, TEM and X-ray diffraction. The thickness of the barrier layer of the porous oxide film was thin and it attributed to the formation of the metal particles, while the formation of the oxide precursor was associated with the surface pits which were developed in the pretreatment of Al.

Ohmic Contact at Al/TiO_2/n-Ge Interface with TiO_2 Deposited at Extremely Low Temperature

TiO2deposited at extremely low temperature of 120°C by atomic layer deposition is inserted between metal and n-Ge to relieve the Fermi level pinning. X-ray photoelectron spectroscopy and cross-sectional transmission electron microscopy indicate that the lower deposition temperature tends to effectively eliminate the formation of GeOxto reduce the tunneling resistance. Compared with TiO2deposited at higher temperature of 250°C,there are more oxygen vacancies in lower-temperature-deposited TiO2, which will dope TiO2contributing to the lower tunneling resistance. Al/TiO2/n-Ge metal-insulator-semiconductor diodes with 2 nm 120°C deposited TiO2achieves 2496 times of current density at-0.1 V compared with the device without the TiO2interface layer case, and is 8.85 times larger than that with 250°C deposited TiO2. Thus inserting extremely low temperature deposited TiO2to depin the Fermi level for n-Ge may be a better choice.

Al homogeneous deposition induced by N-containing functional groups for enhanced cycling stability of Al-ion battery negative electrode

Rechargeable Al-ion batteries(AIBs)are considered as one of the most fascinating energy storage systems due to abundant Al resource and low cost.However,the cycling stability is subjected to critical problems for using Al foil as negative electrode,including Al dendrites,corrosion and pulverization.For addressing these problems,here a lightweight self-supporting N-doped carbon rod array(NCRA)is demonstrated for a long-life negative electrode in AIBs.Experimental analysis and first-principle calculations reveal the storage mechanism involving the induced deposition of N-containing function groups to Al as well as the ideal skeleton of the NCRA matrix for Al plating/stripping,which is favorable for regulating Al nucleation and suppressing dendrites growth.Compared with the Al foil,the NCRA exhibits lower areal mass density(∼72%of Al foil),smaller thickness(40%of Al foil),but much longer cycle life(>4 times of Al foil).Benefiting from the remarkable stability of the array structure,symmetric cells show excellent cycling stability with small voltage hysteresis(∼80 mV)and meanwhile there are no corrosion and pulverization problems even after cycled for 120 hours.Besides,full cells also manifest long lifespan(1,500 cycles)and increased Coulombic efficiency(100±1%).

High performance novel flexible perovskite solar cell based on a low-cost-processed ZnO:Co electron transport layer

In this work,high quality uniform and dense nanostructured cobalt-doped zinc oxide(ZnO:Co)films were used as electron-transport layers in CH3NH3Pbl3-based planar heterojunction perovskite solar cells(PSCs)on a flexible conductive substrate.Highly photo catalytically active ZnO:Co films were prepared by a low cost hydrothermal process using the aqueous solution of zinc nitrate hexahydrate,hexamethylenete-tramine and cobalt(II)nitrate hexahydrate.ZnO:Co films were deposited on indium tin oxide(ITO)covered polyethylene terephthalate(PET)flexible substrates.The growth was controlled by maintaining the autoclave temperature at 150℃for 4 h.The CH3NH3Pbl3 layer was deposited on the ZnO:Co films by spin coating.Spiro-OMeTAD was employed as a hole-transporting material.The structural,morphology and optical properties of the grown ZnO nanostructures were characterized by X-ray diffraction(XRD),field-emission scanning electron microcopy(FESEM),energy-dispersive X-ray spectrometry(EDX),ultraviolet-visible(UV-Vis)and photoelectrochemical propriety.XRD spectra showed that both ZnO and ZnO:Co nanorods had a hexagonal wurtzite structure with a strong preferred orientation along the(002)plane.The surface morphology of films was studied by FESEM and showed that both the pure and Co-doped ZnO films had hexagonal shaped nanorods.In the steady state,the ZnO electrode gave a photocurrent density of about 1.5 mA/cm2.However,the Co-doped ZnO electrode showed a photocurrent density of about 6 mA/cm^2,which is 4-fold higher than that of the ZnO electrode.Based on the above synthesized Co-doped ZnO films,the photovoltaic performance of PSCs was studied.The Co-doped ZnO layers had a significant impact on the photovoltaic conversion efficiency(PCE)of the PSCs.The latter was attributed to an efficient charge separation and transport due to the better coverage of perovskite on the nanostructured Co-doped ZnO films.As a result,the measured PCE under standard solar conditions(A M 1.5G,100 mW/cm^2)reached 7%.SCAPS-1D simulation was also performed to analyze the effect of the co-doped ZnO thin film on the corresponding solar cell performances.