Morphology control of zinc electrodeposition by surfactant addition for alkaline-based rechargeable batteries

ArticlePhysical Chemistry Chemical Physics. 21(13): 7045-7052 (2019)journal articl

Fabrication of Three-Dimensional (3D) Copper/Carbon Nanotube Composite Film by One-Step Electrodeposition

A three-dimensional (3D) composite film containing copper nanostructures and carbon nanotubes (3DC/CNT composite film) was fabricated by one-step electrodeposition. The 3DC/CNT composite film was formed under galvanostatic conditions using a copper sulfate bath containing CNTs and polyacrylic acid which acts as both a 3DC-forming and a CNT-dispersing agent. The composite film consists of thin copper sheets with thicknesses of ca. 70-80 nm and CNTs, with large interior spaces between sheets. The CNTs were homogeneously distributed inside the composite film and were fixed by the copper sheets where CNTs pierce the copper sheets. The CNT content in the composite films increased with the CNT concentration of the plating bath. The 3DC film without CNTs did not maintain its 3D spaces when the film thickness was increased due to insufficient structural strength, whereas the 3DC/CNT composite film maintained the 3D spaces despite an increase in film thickness, which suggests that the CNTs reinforce the film to maintain the 3D spaces. (C) The Author(s) 2016. Published by ECS. All rights reserved.ArticleJOURNAL OF THE ELECTROCHEMICAL SOCIETY. 163(14):D774-D779 (2016)journal articl

Communication-Micro-Scale Columnar Architecture Composed of Copper Nano Sheets by Electrodeposition Technique

Micro-scale columnar architectures composed of copper sheets with nanometer thickness were fabricated by electrodeposition using a photolithography technique. A copper sulfate solution containing a polyacrylic acid was used as the plating bath, and the electrodeposition was conducted under galvanostatic conditions. Patterned electrodeposits with a cylindrical shape and composed of thin copper sheets were formed. Every copper deposit had openings on the top and side regions and also had a porous interior. This novel three-dimensional (3D) copper architecture should provide functional copper electrodes with large effective surface areas. (C) The Author(s) 2016. Published by ECS. All rights reserved.ArticleJOURNAL OF THE ELECTROCHEMICAL SOCIETY. 164(2):D72-D74 (2017)journal articl

Relationship between deformation and stability switching in amorphous metal : local lattice instability analysis

We have attempted to comprehend the deformation behavior of amorphous metals by the local lattice instability analysis that discusses the positiveness of atomic elastic stiffness coefficients, Bα ij, or the second-order derivatives of atomic energy composition. In the present study, we discuss the stability-switching, or transitions between detBα ij ≥ 0 and detBα ij < 0, by the “probabilistic” fluctuation and the “deterministic” mechanical load. No-load equilibrium, tension, compression and simple shear are performed on an amorphous nickel by molecular dynamics simulations. The positive and negative stability-switching, or “stabilization” and “destabilization”, occur due to the “probabilistic” fluctuation even at the equilibrium state. The number of detBα ij < 0 atoms shows almost constant while the distribution of detBα ij < 0 atoms indicates different morphology at each observation time. Ratios of switched atoms with stability-switching under tension, compression and shear are larger than that under the equilibrium because the local structural relaxation produces simultaneously both positive and negative stabilityswitching. Atoms with negative and positive stability-switching show increases and decreases of atomic volume, respectively; while only positive switching shows the decreases in local volumes, evaluated with the atomic volumes of surrounding atoms within the cutoff radius, according to the incidence of “deterministic” structural changes

Li-insertion/extraction properties of three-dimensional Sn electrode prepared by facile electrodeposition method

Toward the realization of reliable Li-ion batteries with high performance and safety, component materials such as those of the current collector and negative electrode require further innovation. Sn, one of the most promising negative-electrode materials, can be electrochemically fixed on a substrate without any binder or conductive additive. However, the pulverization of Sn-plated films on substrates caused by large volume changes during Li-Sn reactions is the main reason hindering the practical application of Sn-plated electrodes. In the present study, we developed an electrodeposited three-dimensional (3D) Cu substrate applied to underlayer of the electrode. The effect of substrate geometry on the charge-discharge performance of the Sn electrode was investigated. The 3D-Cu/Sn electrode exhibited superior cycling performance with a reversible capacity of 470 mA h g(-1) even at the 300th cycle, whereas the Sn-plated electrode prepared on a typical flat Cu substrate showed a capacity of only 20 mA h g(-1). The results demonstrated that the 3D structure played a key role in accommodating volumetric changes in the Sn to suppress electrode disintegration. The developed 3D-Cu substrate will be significantly useful as a current collector for alloy-based active materials. [GRAPHICS] .ArticleJOURNAL OF APPLIED ELECTROCHEMISTRY.47(6):727-734(2017)journal articl

Suppressing the effect of lithium dendritic growth by the addition of magnesium bis(trifluoromethanesulfonyl)amide

Practical applications of Li-S and Li-air batteries require the morphology of the Li metal negative electrode during charge/discharge (i.e., Li-deposition/dissolution) cycling to be precisely controlled. Herein, we used magnesium bis(trifluoromethanesulfonyl)amide [Mg(TFSA)(2)] as an electrolyte additive to suppress the growth of Li dendrites, utilizing the occurrence of an alloying reaction between the initially substrate-deposited Mg and the subsequently deposited Li. Notably, no metallic Mg formation and no change in Li deposition morphology were observed at an electrolyte composition of 0.1 M Mg(TFSA)(2) + 0.9 M LiTFSA/triglyme, irrespective of the applied potential. In contrast, increasing the Mg salt concentration to 0.5 M resulted in the deposition of interconnected granules, reflecting a dramatic morphology improvement. X-ray diffraction analysis revealed the occurrence of the abovementioned alloying, which finally afforded a deposit composition of Li0.9Mg0.1 via the formation of an intermediate Li0.14Mg0.86 phase. Importantly, the deposits obtained under various applied potentials were relatively smooth, with no needle-like morphology observed.ArticlePHYSICAL CHEMISTRY CHEMICAL PHYSICS.20(2):1127-1133(2018)journal articl

Nanofixation with Low Melting Metal Based on Nanorobotic Manipulation

IEEE-NANO 200

Communication—Alkyl-Chain-Length Dependence of Quaternary Ammonium Cation on Zn Deposition Morphology in Alkaline-Based Electrolytes

ArticleJournal of The Electrochemical Society. 166(10): A2242 (2019)journal articl