bluuebunny/crossref_metadata_2025 huggingface dataset:
Mechanical Properties of Electrodeposited Al-W Alloy Films and the Effects of Subsequent Heat Treatment
Authors: Higashino Shota , Takahashi Ayumu , Kasada Ryuta , Miyake Masao , Hirato Tetsuji
Published: February 2020

Due to their high oxidation and corrosion resistance, Al coatings are effective in extending the lifetimes of other metallic materials. However, the low mechanical strength of Al can limit its adoption for certain applications. Alloying Al with other transition metals, which improves the mechanical properties, can be a possible solution to this problem.

Electrodeposition is a simple method of forming Al-base alloy films from ionic liquids represented by EMIC-AlCl3. Among the Al-base alloys, Al-W alloy is of significant interest since it is expected to exhibit excellent mechanical properties. The electrodeposition of Al-W alloys from EMIC-AlCl3 baths containing K3W2Cl9 was reported previously[1]. However, Al-W alloys electrodeposited from this system had a powdery morphology when the W content was >7 at.%, and the mechanical properties have not been investigated.

In this study, we report the electrodeposition of Al-W alloy films from EMIC-AlCl3 baths containing WCl2. Nano-indentation tests were undertaken to determine the hardness and Young’s modulus of the Al-W alloy films. The effects of heat treatment on the mechanical properties were also examined.

It was possible to electrodeposit Al-W alloy films containing up to 12 at.% W. XRD patterns showed that these films were fcc solid solution at low W contents, and were amorphous at 12 at.% W. The hardness increased from 1.8 GPa with increasing W content. The film containing 12 at.% W showed the highest hardness value of 4.6 GPa, which is close to that of pure bulk W. The Young’s modulus also increased from 97 to 168 GPa with increasing W content in the solid solution range, followed by a sudden decrease to 89 GPa at 12 at.% W. This value is close to that of pure bulk Al. The low Young’s modulus of Al-12 at.% W alloy is attributed to its amorphous structure. Heat treatment at 300-400°C for 3 h was carried out. After the heat treatment at 400°C, Al-W intermetallic compounds were detectable by XRD, and both the hardness and Young’s modulus increased.

These results show that Al-W alloy films with excellent mechanical properties can be obtained from EMIC-AlCl3-WCl2baths. In particular, amorphous Al-12 at.% W films displayed interesting properties, including hardness values as high as that of W and Young’s modulus values as low as that of Al. The hardness and Young’s modulus of Al-W films can be controlled by modifying the W content and conducting subsequent heat-treatment.

[1] T. Tsuda et al., Journal of the Electrochemical Society 161, D405-D412 (2014)
Gradient Morphologies in Electrodeposited Manganese Dioixde and Their Effect on Electrochemical Performance
Authors: Donne Scott W , Fellows Hannah , Beyad Yaser
Published: February 2020

In this study, the use of current and potential control techniques in production of electrolytic manganese dioxide (EMD) has led to insight into the behaviour of different morphologies of manganese dioxide for a number of chemical storage systems. Further, improvements on industrial milling have been considered. Manganese dioxide has an advantage of existing in a variety of phases, and it has been found that current density greatly influences crystal structure along with deposit densities. Through the manipulation of this factor during the depositing of EMD a variety of morphologically different deposits can be obtained, linking to advantages for a number of industrial applications.

Techniques such as chronopotentiometry and chronoamperometry have allowed for insight into the application of step potential ramps, multilayer depositions, and the manipulation of pulse sequences in a series of EMD deposits to be morphologically investigated through techniques such as scanning electron microscope (SEM) and X-ray diffraction (XRD) along with electrochemical performance testing.

The objective of this study has been to provide a real world application, and superior performance essentially allowing for an alternative to bulk depositing. The study has considered specialised purposes such as industrial milling i.e. improving fracturing capabilities along with battery/capacitor applications with these deposits aiming to highlight the importance of improved electrolyte transport with regard to cathode interaction.
Ionic Liquid-Assisted Electron Transfer in Micelles for Simultaneous Deposition of Uniform Ag Nanoparticles at Electrode Surface and in Bulk Microemulsions
Authors: Wang Zenglin , Li Yuhan , Zhao Chuan
Published: February 2020

The synthesis of metal nanoparticles (NPs) with controllable size from aqueous or organic solutions has long been a scientific and technological challenge. Here we show a unique electrodeposition approach from ionic liquid microemulsions (ILM) which enables simultaneous fabrication of uniform controllable Ag NPs at both electrode substrate and in bulk solution. In the ILM system containing cetyltrimethylammonium bromide (CTAB), butanol, 1-butyl-3-methyl-imidazolium chloride ([BMIM][Cl]), and an aqueous solution of silver nitrate, uniform Ag NPs with a narrow size distribution of 20 ~ 50 nm could be electrodeposited on the cathode surface at low deposition current (0.2~1.5 mA·cm-2). The size and size distribution of Ag NPs can be adjusted by tuning the deposition current, time, temperature and IL concentrations. Remarkably, at high deposition current (>1.50 mA·cm-2) the electrochemical reduction of Ag NPs takes place not only on the electrode surface but also beyond into the bulk microemulsion phase. Uniform Ag NPs of diameters 2 ~ 13 nm thus can be obtained from the bulk ILMs. It is found that the ionic liquid plays a quaternary role as a soft template and co-surfactant for the formation of micro-reactors, an electrolyte for enhancing conductivity, and an electron carrier facilitating electron transport between nanodropletsfor Ag reduction. The electrocatalytic activity of the electrodeposited Ag NPs has been investigated for oxidation of glycerol for potential applications in direct alcohol fuel cells.
On the Dynamics of Solid Oxide Fuel Cell Stacks: Preliminary Model-Driven Design and Control
Authors: Boigues Muñoz Carlos , Abate Lorenzo , McPhail Stephen J.
Published: February 2020

The inexorable inclusion of high temperature fuel cells in the energy grid of the world’s major economies accentuates the needs for more robust systems capable of tolerating non-stationary conditions with minor degradation. It seems undeniable that the latter needs to be addressed mainly by basic and applied research on the fuel cell stack components (electrodes, interconnects, etc…), yet there is still space for performance improvement by optimising system integration.

This paper encompasses the experimental procedure used to fully characterise a 6-cell intermediate temperature solid oxide fuel cell (IT-SOFC) short stack when operating in non-stationary conditions and in dissimilar load demands, fuel flows, fuel utilisations and temperatures, simulating to some extent a real-life appliance capable of following electrical load and/or heat demand. The spanning of such input factors allows generating a space-matrix of variables – voltages, temperatures and output gas compositions – that describe the system’s dynamic and stationary performance considering null degradation. This experimental approach can produce appropriate values so as to generate simple autoregressive models suitable for real-time one-step-ahead predictions of the output variables. In this work, the most effective mathematical correlation between the numerous inputs and outputs resulted to be a non-linear autoregressive exogenous (ARX) model built by means of a treepartition algorithm (i.e. binary search trees). The normalised root mean square error (NRMSE) of the calculated fit of the train data was above 94% in all of the cases denoting that the model simulates exceptionally well the system’s outputs in the studied ranges.

Additionally, the model was validated with test data, more particularly a dynamic current-voltage curve, and the results show how the simulated points follow remarkably well the experimental results. It must be noted that the electrical current imposed to the SOFC stack in the test data ranged from 5A to 20A, which is the range in which the model performs best; nevertheless outside these bounds the model is capable of simulating exceptionally well the voltage output, especially at high current densities.

This dynamic model can be of great use for preliminary design & control of power plants incorporating nominal size stacks from the same manufacturer/integrator by increasing the understanding of how the plant will perform when in transient conditions. Furthermore, the present model is capable of assessing online the degradation rate of a fuel cell stack by comparing the experimental results with the expected ones from the model.
Experimental and Numerical Study of Small Lead Acid Batteries Regeneration
Authors: Astier Francois , Mandin Philippe , Boyer Geremy , Merdrignac Odile , Noiret Nicolas
Published: February 2020

Battery ageing and performance evolution prediction is one of the energy management key. The use of lead acid batteries is always strong despite its weight and the constant increasing, of new battery materials and technologies. The lead acid batteries are mainly used to start car engine or as primary energy source for forklift or pallet trucks. Another application is the storage of electrical energy produces by intermittent energy sources like photovoltaic, wind or tidal powers. Multiple factors influence lead acid batteries ageing depending of the type of batteries technology (vented or opened and VRLAB or sealed) and the kind of use. We focus our experimental study on four of them: the number of ageing cycles (1), the operating current (2), the temperature (3) and the use of electrolyte additives, containing EDTA (4). Factors are investigated on two levels (Table 1).

Figure 1
Electrochemical Behaviour of Industrial IrO2-Ta2O5 Anodes for Copper Electrowinning
Authors: Xu Wenting , Haarberg Geir Martin , Sunde Svein , Seland Frode , Ratvik Arne petter , Zimmerman Erik , Åkre Torjus
Published: February 2020

Lead-based anodes are widely used in copper electrowinning (EW). However, lead can induce contamination of the electrolyte during copper EW due to the corrosion of the anode [1]. Furthermore, corrosion while at high current densities will finally lead to the failure of the anode since the overvoltage for oxygen evolution reaction (OER) on lead is still rather high, and the service life of lead-based anodes is quite limited in industrial copper plants [2]. Besides, lead and lead compounds are toxic, which means the use of lead-based anodes is not environmentally friendly. Dimensionally stable anodes (DSAs) with IrO2-Ta2O5 oxides coated on titanium substrates hold excellent electrocatalytic activity and electrochemical stability, and have the most potential to replace lead-based anode in copper EW industry.

In this work, different types of commercially available electrode samples with IrO2-Ta2O5 coating were studied. The studies focused on investigating the impact of surface microstructure on electrocatalytic activity. Surface morphology and chemical composition of DSA samples were analyzed using scanning electron microscopy (SEM, Hitachi S-3400N) combined with energy dispersive spectroscopy (EDS). X-ray diffraction (XRD) studies were carried out using Bruker AXS D8Advance with grazing incident angle at 3°. The crystalline structure and phase composition were analyzed by varying the 2θ angle from 10° to 80°. The electrochemical experiments were carried out in aqueous solution with 0.9 M H2SO4 and 1.2 M CuSO4. A Teflon holder giving a 1 cm2 electrode surface area was used. All experiments were conducted at 60 °C. Cyclic voltammetry (CV) measurements were recorded in a range between 0.55 V and 1.35 V vs. SHE with varying sweep rate from 300 mV/s to 1 mV/s. The scan rate for all polarization measurement was 0.5 mV/s. The ohmic (IR) drop during the testing was corrected for by measuring the electrolyte resistance using electrochemical impedance spectroscopy (EIS) at high frequency. Electrocatalytic activity for anodes as a function of composition and preparation method was determined by steady state polarization analysis. The durability of the anodes was investigated by accelerated lifetime tests, which were carried out in 0.9 M H2SO4 solution at the constant current density of 2 A/cm2.

In the present work, commercial DSAs were used instead of samples fabricated in the laboratory. This offers not only valuable results for DSAs research but also a consideration for DSAs manufacturers to improve the quality of the DSA.

[1] M. Clancy, C. J. Bettles, A. Stuart, N. Birbilis, Corrosion behaviour and catalytic effectiveness of Pb–Ca–Sn, RuO2 –IrO2 /Ti and IrO2 –Ta2O5/Ti anodes for copper electrowinning, Hydrometallurgy 131-132 (2013) 144.

[2] G. N. Martelli, R. Ornelas, G. Faita, Deactivation mechanisms of oxygen evolving anodes at high current densities, Electrochim. Acta 39 (1994) 1551.
A Generalized Numerical Method for Approximating Equilibrium Reactions for Electrochemistry Simulations
Authors: Lange Kyle , Goldin Graham , Lueth Chris , Walchshofer Christian , Makridis Alexandros
Published: February 2020

Many electrochemistry applications such as wet-etching, flow-batteries and electroless deposition involve equilibrium reactions, chemical reactions which instantaneously reach an equilibrium state. The equilibrium state is defined by the equilibrium constant which specifies an algebraic constraint on the molar concentrations of participating species in the reactions. The simulation of electrochemistry applications which involve both ion transport and equilibrium reactions is particularly challenging because the system of equations is over-constrained.

Previous approaches for solving this combined set of reaction / transport equations have involved equation substitution or solving combinations of equations along with elemental conservation. The resulting implementations have been specific for particular problems and are difficult to implement for the most general case. In this work, we present a new algorithm which can be generalized for any set of equations and provides an efficient, approximate solution for both ion transport equations and equilibrium chemistry. Example validation results are provided along with a discussion of the limitations of the approach.
Electrochemical Oxidation of Lignin for Production of Value Added Chemicals
Authors: Ghahremani Raziyeh , Staser John A
Published: February 2020

Electrochemical oxidation of lignin for production of value added chemicals

Raziyeh Ghahremani and John A. Staser (Center for Electrochemical Engineering Research, Department of Chemical and Biomolecular Engineering, Ohio University)

 

The polyphenolic structure of lignin makes it the ideal raw material to produce commercial aromatic compounds[1]. However, due to the difficulty of the conversion process of lignin, it is usually burned to produce heat and energy[2]. Electrochemical oxidation is an environmentally friendly, inexpensive, and efficient depolymerization process which can take place at relatively low pressure and temperature, and the reaction can be controlled by potential or current[1]. However, high cost of materials for preparing electrodes, also deactivation of the electrode during the reaction due to impurities makes electrochemical oxidation processes more elaborate and expensive, prohibiting its broad application[3]. Therefore, it is critical to develop a low cost and efficient electrode for the electrochemical oxidation of lignin.

In this work, the inexpensive Ni-Co electrocatalysts were developed for use in the electrochemical oxidation of lignin to produce other value added chemicals. We have developed nanoparticle electrocatalysts that are suitable for a continuous flow electrochemical reactor to be integrated into existing biorefineries. Gas chromatography and mass spectroscopy (GC-MS) was applied to analyze the products and the results showed that valuable chemicals like vanillin, apocynin and other aromatic compounds are produced by the electrochemical oxidation of lignin, the concentration of chemicals also were increased during the time of oxidation. We will also present techno-economic analyses that can be used as a benchmark for integrating the electrochemical reactor into the biorefinery.

[1] O. Movil, M. Garlock, and J. A. Staser, “Non-precious metal nanoparticle electrocatalysts for electrochemical modification of lignin for low-energy and cost-effective production of hydrogen,” Int. J. Hydrog. Energy, vol. 40, no. 13, pp. 4519 – 4530, 2015.

[2] D. Klein-Marcuschamer, P. Oleskowicz-Popiel, B. A. Simmons, and H. W. Blanch, “Technoeconomic analysis of biofuels: A wiki-based platform for lignocellulosic biorefineries,” Biomass Bioenergy, vol. 34, no. 12, pp. 1914 – 1921, 2010.

[3] Y. Zhang, Y. Peng, X. Yin, Z. Liu, and G. Li, “Degradation of lignin to BHT by electrochemical catalysis on Pb/PbO2 anode in alkaline solution,” J. Chem. Technol. Biotechnol., vol. 89, no. 12, pp. 1954–1960, 2014.
Preparation of Multi-Walled Carbon Nano-Tube Composite Copper Plating from Acidic Solution
Authors: Kamebuchi Yota , Kamimoto Yuki , Ichino Ryoichi , Bessho Takeshi
Published: February 2020

Copper has excellent thermal properties including thermal conductivity; therefore copper has been used as the thermal heat dissipation materials. However, the materials with more excellent thermal properties are needed for the increasing of the packaging density of electronic equipment. The authors have focused on the excellent thermal properties of Multi-Walled Carbon Nano-Tube (MWCNT). MWCNT has excellent thermal properties, mechanical properties and electrical properties, then, it is expected to be applied to various fields such as electronic component, semiconductor, medical, biotechnology and so on. It was considered that the thermal properties of the copper plating could be greatly improved by compositing MWCNT with copper plating. The purpose of this study is to prepare MWCNT composite copper plating with more excellent thermal properties than conventional copper plating. MWCNT composite copper plating was obtained from the copper sulfate bath with suspended MWCNT by general electrolytic method. Various plating conditions had been investigated in order to increase the content of MWCNT in the films such as the concentration of MWCNT and pH of the plating baths, surfactant, current density, film thickness and agitation speed were researched. The content of MWCNT in the films was measured by combusting the samples in oxygen atmosphere and measuring amount of generated gas, CO and CO2, by infrared absorption method.

There were optimal conditions for preparing the composite copper plating with higher amount of MWCNT. It should be noted, that the higher amount of MWCNT in the films increased the thermal conductivity of the films, but that the using additives for MWCNT dispersion reduces the thermal conductivity comparing to the copper plating without additives by the thermal conductivity measurement.

Then the authors also focused on the hydrothermal treatment to MWCNT in various acidic solutions as a method that used no additives. It was effective for improvement of the amount of MWCNT in the films. The samples containing the largest amount of MWCNT was prepared when using MWCNT treated in mixed acid of sulfuric acid and nitric acid at the ratio of 3 to 1 at 150 °C for 2 hours. The MWCNT content in the copper film was 1.01 mass%, which was maximum value in this study. The sample which was prepared using hydrothermal treated MWCNT, without using addition agent, had slightly higher thermal conductivity than that of the conventional copper plating without additives.
(Invited) Memcomputing (Memristor + Computing) in Intrinsic SiOx-Based Resistive Switching Memory
Authors: Chen Ying-Chen , Wu Xiaohan , Guo Meiqi , Zhou Fei , Chang Yao-Feng , Fowler Burt , Pan Chih-Hung , Chang Ting-Chang , Lee Jack C.
Published: February 2020

This study focuses on memcomputing (Memristor + Computing) in intrinsic SiOx-based resistive switching memory. Specifically, we investigate neuromorphic computing by a device with biological synaptic behaviors in integrating silicon oxide (SiOx) resistive switching memory with Si diodes. Minimal synaptic power consumption due to sneak-path current has been achieved and the capability for spike-induced synaptic behaviors has been  demonstrated, representing critical milestones for the application of SiO2–based materials in future neuromorphic computing. The detailed biological synaptic behaviors such as long-term potentiation (LTP), long-term depression (LTD) and spike-timing dependent plasticity (STDP) are demonstrated systematically using a comprehensive analysis of spike-induced waveforms. We will also discuss a implementation technique of implication operations by using SiOx-based memristors in TaN/SiOx/Si. The implication function and its truth table have been implemented. The key factors for the operation of material implication, such as load resistance, characteristics of the memristor, and design tradeoffs have been investigated. Furthermore, we have demonstrated implication operation using a circuit with two SiOx-based memristor and CMOS transistor. A circuit with two one-diode and one resistor (1D-1R) memory elements and a transistor are designed to perform implication operations. A circuit consisting of a 4 × 4 crossbar structure 1D1R memristor array together with the select transistors is proposed. Based on this circuit, a total of 48 steps of operations are performed to realize the functionality of a one bit full adder. The advantages and disadvantages of the memristor enabled logic circuit are compared with CMOS logic circuits. The experimental results suggest a simple, robust approach to realize programmable memcomputing chips compatible with large-scale CMOS manufacturing technology.

(* This paper is invited by ECS 2016 Honolulu Meeting.)
Studies of Parylene C Microfibrous Thin Films Electrical Properties
Authors: Khawaji Ibrahim H , Awadelkarim Osama O. , Lakhtakia Akhlesh
Published: February 2020

Parylene C is known for its flexibility, transparency, biocompatibility, and dielectric reliability. Parylene C is, hence, researched for use as a gate dielectric in transistors and capacitors for flexible electronics as well as for nano/microelectromechanical system applications [1-3]. In this study, we use metal–insulator–metal (MIM) capacitor structures to examine the electrical characteristics of columnar microfibrous thin films (µFTFs) of Parylene C prepared using oblique-angle physicochemical deposition [4,5], whereby a collimated vapor Parylene C is directed at an angle χv with respect to the exposed face of a planar substrate. The values of χv used were 30°, 60°, and 90°. We found that the low-frequency relative permittivity of the columnar µFTF increases with χv. This is explained in terms of the porosity as a function of χv, the porosity being higher for lower χv. Leakage current and charge deep-level transient spectroscopy (Q-DLTS) measurements at temperatures in the 230–470 K range and at frequencies in the 1–1000 kHz range were used to evaluate the dielectric integrity of the columnar µFTFs. Observed capacitance transients and Q-DLTS peaks in temperature were analyzed to uncover carrier traps located in the Parylene C bulk and at the metal/Parylene C interfaces in the MIM structures. The variations of DC and AC conductivities can be explained in terms of charge transport mechanisms involving thermionic emission and electron hopping.

W. T. Wondmagegn, N. T. Satyala, I. Mejia-Silva, D. Mao, S. Gowrisanker, H. N. Alshareef, H. J. Stiegler, M. A. Quevedo–Lopez, and B. E. Gnade, Thin Solid Films, 519(13), 4313–4318 (2011).

T. Trantidou, D. J. Payne, V. Tsiligkiridis, Y.-C., Chang, C. Toumazou, and T. Prodromakis, Sensors and Actuators B: Chemical, 186(1), 1–8 (2013).

B. Park B., K-J. Im, K. Cho, and S. Kim, Organic Electronics, 9(5), 878–882(2008).

C. Chindam, N. M. Wonderling, A. Lakhtakia, O. O. Awadelkarim, and W. Orfali, Applied Surface Science, 345(1), 145–155 (2015).

Khawaji, I. H., Chindam, C., Orfali, W., Awadelkarim, O. O., Lakhtakia, A. ECS Transactions, 69(5), 113-119 (2015).
(Invited) Control of Atomic Layer Reactions in Plasma Processing
Authors: Ventzek Peter , Sherpa S D , Wang M , Rastogi V , Ranjan Alok
Published: February 2020

Self-limiting chemistries in plasma processes offer a pathway to addressing many process trade-offs associated with profile, selectivity, film quality/surface sub-surface damage and uniformity. Self-limiting plasma processes for etch and deposition are referred to as atomic layer processes for their promise of modification of surfaces with atomic layer precision. The efficacy of atomic layer processes depends in large part on the precursor specie-substrate material pairing that forms reactive layers on surfaces. The reactive layer is to be volatilized in a subsequent step the case of atomic layer etching and primed for further reactions in atomic layer deposition. As much as the precursor itself (e.g., chlorine radicals), the surface condition itself plays a considerable role in the ability of a chemical change to take place on the surface. The surface condition represents itself in limiting the coverage or even in slowing the start of a process. This slowing is well known in atomic layer deposition as incubation time. In plasma processes that seek processing with atomic precision, how the surface can be described in complicated by the presence of ions which may introduce defects on or below the surface depending on their energy and nature or drive chemical reactions. Results from fundamental atomistic simulation techniques are used to show how the details of the surface state (i.e., crystalline, amorphous, terminated in different ways) impact process. Halogen coverage in silicon etch will be used as a backdrop for illustrating surface conditioning effects on more involved processes such as those on nitride or oxide surfaces. Finally, we will illustrate how the solid state chemistry of the sub-surface can impact electrical functionalization of semiconductor devices. We will show how simulation results (macroscale to atomistic) work hand-in-hand to with experiment to demonstrate processes benefiting from self-limitation.
Infrared Study of Room Temperature Atomic Layer Deposition of SnO2 Using Sn(CH3)4 and Plasma Excited Humidified Argon
Authors: Hirose Fumihiko , Tokoro Kentaro , Kanomata Kensaku , Miura Masanori , Ahmmad Bashir , Kubota Shigeru
Published: February 2020

Tin oxide (SnO2) is an oxide semiconductor material with an excellent optical transparency, where it is used as transparent conducting films. It is also used as a channel material for gas sensors. Recently atomic layer deposition (ALD) of SnO2 has been studied intensively since ALD allows the conformal deposition of the oxide film with an atomic level precision. However, the high process temperature in excess of 100 °C in the conventional SnO2 ALD is a major problem for its application for flexible electronics. We developed a room temperature deposition technique with a precursor of tetramethyl tin (Sn(CH3)4, TMT) and plasma excited humidified argon. The surface reaction of the precursor adsorption and its oxidization were monitored by infrared absorption spectroscopy (IRAS) with a multiple-internal-reflection (MIR) geometry.

A p-type Si(100) substrate with a resistivity of 8-12 Ωcm was used as a sample. Prior to the experiment, the sample was cleaned with buffered HF acid and sulfuric acid-hydrogen peroxide mixture solutions. The Sn precursor of TMT was introduced with a variable leak valve. A plasma excited humidified argon source was installed to the ALD chamber as shown in Fig. 1. The source gas for OH-radical is a mixture of H2O vapor and Ar made by a water bubbler. The plasma was generated in a glass tube with an induction coil with a frequency of 13.56MHz and a RF power of 30 W. Before the ALD process, the substrate surface was treated with the plasma excited humidified argon for 5 min to be terminated with Si-OH. For the SnO2 deposition, we repeated the cycle of TMT saturation and plasma excited humidified argon at RT. The condition of TMT saturation and oxidization were determined by the MIR-IRAS experiment. In this experiment, the TMT saturation exposure and oxidization time were 2×105 Langmuir and 10 min, respectively. The oxidation state of the SnO2 film was evaluated by X-ray photoelectron spectroscopy (XPS). The thickness of the grown film was measured by spectroscopic ellipsometry.

In Fig. 2, we show Sn 3d XPS spectra obtained from the RT grown SnO2 film, where we confirm the evolution of full oxidized state peak according to the increase in the ALD cycle number. We calculated the growth per cycle as 0.02 nm/cycle. In the conference, we present the results of RT ALD of SnO2 and discuss the surface-reaction mechanism based on the IRAS observation. 

Acknowledgement; This work was partly supported by JST-CREST, JSPS KAKENHI Grant Numbers 15H03536 and 15K13299.

Figure 1
Atomic Layer Deposited Metal Oxides Films for Solar Cells
Authors: Kim Do-Heyoung
Published: February 2020

Direct utilization of sunlight into electrical power is of great interest as a clean and safe energy source. Among various types of solar cells, Si-based solar cells can yield high power conversion efficiency and thus, is in mass production for practical usage. However, the expensive fabrication cost of the Si-based solar cells stimulated a research for alternative types of solar cells. Dye-sensitized solar cells (DSSCs) and polymer solar cell (PSC) are considered as the promising candidates for the partial replacement of Si-based solar cell due to its advantages of low cost, easy fabrication, and moderate power conversion efficiency compared Si-based solar cells. Here, the effect of atomic layer deposited (ALD)-metal oxides thin films on the device performance of DSSC and PSC will be presented.
A Synthesis Approach of Cu Nanoparticles Using Polyimide As a Template and Their Application on a Printed Circuit Board
Authors: Tsai Yao-Lin , Chung Yi-Chun , Dow Wei-Ping , Hashimoto Yasuo
Published: February 2020

Electroless deposition process has been commonly used for the metallization of through holes of a printed circuit board (PCB). It is well-known that Sn/Pd colloid is widely used as the catalyst for catalyzing Cu electroless deposition onto the sidewalls of the through holes, composted of glass fiber and epoxy resin. However, Pd is very expensive. In addition, if IC substrate is fabricated using a semi-additive process (SAP), the residual Pd catalysts on the resin surface of the IC substrate, which has catalyzed a layer of copper electroless film, have to be removed from the resin surface after copper electroplating to prevent short between two copper lines. The SAP cost is accordingly high. To overcome these issues, copper nanoparticles (CuNPs) were synthesized using a heterogeneous reaction rather than a homogeneous reaction. Polyimide (PI) film was employed as a template to store copper ions. The CuNPs were gradually formed after the Cu2+-doped PI was transferred into a solution, containing a reducing agent and a ligand. The CuNPs were characterized by UV-Vis, FE-SEM, HR-TEM, ESCA, FT-IR, Zeta potential and XRD. Their mean particle size was smaller than 10 nm and varied from 4 to 6 nm and has a strong Cu (111) orientation. Therefore, they were able to perform a high catalytic activity for Cu electroless deposition.
Challenges and Issues Facing Lithium Metal for Solid State Rechargeable Batteries
Authors: Zaghib Karim , Mauger A , Julien C.M , Armand M
Published: February 2020

Research on lithium metal combined with polymer electrolyte in lithium rechargeable batteries was started in 1979. Since that time, lithium battery research has expanded worldwide. Several new polymers, solid electrolytes and ionic liquids with improved conductivity were identified. These advances resulted from a better understanding of the major parameters controlling ion migration, such as favorable polymer structure, phase diagrams between solvating polymers and lithium salts, and the development of new lithium counter-anions. In spite of the progress so far, the quest for a highly conductive dry polymer at room temperature is still not available. However, effort is continuing, and all-lithium polymer battery (LPB) developers presently face the challenge of whether to heat the polymer electrolyte to enable high-power performance, as required for electric vehicles and energy storage. LPB developers have explored both the high-temperature and low-temperature options.

The commercial use of lithium metal/polymer batteries has been delayed because of the adverse effects of dendrites on the surface of the lithium electrodes, and the difficulty in finding a polymer that has both the mechanical strength and ionic conductivity required in a solid electrolyte. However, recent strategies have emerged to overcome these difficulties, and now these batteries are currently an option for different applications, including electric cars.

In this presentation, we review these strategies and discuss the different promising routes that should result in further progress on lithium metal/polymer batteries in the near future. This presentation also discusses the challenges and opportunities in developing thin lithium negative electrodes with stable SEI layers for three battery technologies using:

All solid-state Li-sulfur batteries

Rechargeable lithium batteries containing dry polymer and ionic liquid-polymer electrolytes

3. Li-air batteries.

In addition, we will discuss the safety of lithium, dendrite mechanism, interface phenomena, side reactions, protection of lithium metal, and lithium alloys that are relevant to lithium batteries.

Acknowledgement: The author thanks the SCE IREQ and LTE Shawinigan teams for helpful discussion.
Dimensionally-Stable Lithium Insertion Material of LiCoMnO4 for Long-Life Lithium-Ion Batteries
Authors: Ariyoshi Kingo , Yamamoto Hiroya
Published: February 2020

Lithium insertion materials of LiMO2 (M; transition metal ions) change in their lattice dimensions during lithium insertion and extraction reactions (charge and discharge) due to change in ionic radius of transition-metal ions. Dimensional instability of lithium insertion materials resulting from change in lattice dimension causes particle fracture which leads to a deterioration of lithium insertion electrodes. One of the approaches to achieve long cycleability of lithium insertion electrodes is to minimize change in lattice dimension during charge and discharge. The zero-strain lithium insertion material of the lithium titanium oxide (Li[Li1/3Ti5/3]O4; LTO) is one of the ideal electrode materials for long-life applications, because it shows no change in lattice dimension during charge and discharge. LiCo1/3Ni1/3Mn1/3O2, in which lattice volume is constant in the charge capacity below 180 mAh/g, exhibits excellent cycleability. In this paper, we report dimensionally-stable positive electrode material of LiCoMnO4, which is high operating voltage at ca. 5 V with small change in lattice dimension (< 1 %).

 Highly-crystallized LiCoMnO4 was prepared by a two-step solid-state reaction, i.e., crystallization at a temperature above 900oC and oxidation below 700oC. When a Li / LiCoMnO4 cell was cycled in the voltage range in 3.0 – 5.4 V, discharge capacity was ca.120 mAh g-1 for the initial 3 cycles, which is 83% of the theoretical capacity (145 mAh g-1). In order to examine the change in crystal structures of the LiCoMnO4, the ex-situ XRD examination was carried out. A cubic lattice parameter of LiCoMnO4 contracted during charge, 8.06 Å at initial state and 8.00 Å at fully charged state. The change in lattice parameter of LiCoMnO4 was calculated to be 0.7 %, which is smaller than other lithium insertion material having spinel structure (ca. 2 %). To confirm dimensional stability of a LiCoMnO4 electrode, dilatometry of a LTO/LiCoMnO4 cell by means of high-precision dilatometer was carried out. Figure shows the dilatometric signal together with the cell voltage as function of time. Since the LTO negative electrode is a zero-strain lithium insertion electrode, a change in thickness of the cell corresponds to that of LiCoMnO4 electrode. The LiCoMnO4 electrode contracted during charge and expanded during discharge and a change in electrode thickness was only 0.5 % based on initial electrode thickness, which agrees well with the change in lattice dimension of LiCoMnO4.

From these results, we will describe crystal structure and electrochemistry of dimensionally-stable material of LiCoMnO4 and discuss its reaction mechanism with emphasis on dimensional change.

Figure 1
Paper-Based Ultra-High-Capacity Lithium-Ion Cell for Flexible Electronics
Authors: Liu Yadong , Aliahmad Nojan , Xie Jian , Agarwal Mangilal
Published: February 2020

Flexible, ultra-thin, lightweight energy storage and conversion devices as power sources are in high demand for use in flexible, portable and wearable electronic devices with unusual shape diversity1. Among various power source systems for flexible electronic devices, flexible lithium-ion batteries have attracted great attention due to their high specific energy, high specific power, long cycle life and environmental friendliness2. However, conventional lithium-ion batteries with fixed sizes and shapes can be electrically shorted or cause fire/explosion when bent or stretched.

To meet growing demands for flexible batteries, we take an unique approach where a layer-by-layer (LbL) deposited CNT paper-based current collector is used for both anode and cathode to enable flexibility of the cell. In addition, a gel-polymer electrolyte is used to minimize the amount of liquid electrolyte in the system, and a V2O5/graphene composite (specific capacity: 438 mAh/g) and a silicon/graphene based material (specific capacity: >1000 mAh/g) are used as the cathode and anode materials, respectively. The resulting cell, with a flexible/bendable feature and high specific energy shows promise as a candidate power source for flexible electronic devices.

 ADDIN EN.REFLIST  (1) Gates, B. D. Science
2009, 323, 1566.

(2) Zhou, G.; Li, F.; Cheng, H.-M. Energy & Environmental Science
2014, 7, 1307.

Figure 1
Hierarchical Porous Carbon Derived from Low-Cost Sucrose for Advanced Lithium-Sulfur Batteries
Authors: Liu Heng , Xiang Ming Wu
Published: February 2020

As we all know that lithium sulfur (Li/S) batteries with high theoretical specific capacity (1675 mAh g-1), low-cost and natural abundance are one of the most promising candidates of the high energy density storage systems. However, there still exists many issue such as inherent non-conductivity of sulfur and insoluble discharge products, volume expansion, and shuttling effect. In this work, a type of hierarchical porous activated carbon (HPAC) derived from low-cost sucrose has been successfully prepared via chemical activation and graphitization at low temperature of 600oC. The N2 adsorption-desorption isotherms and pore size distribution profiles of the as-prepared activated carbon were characterized by BET measurement. The HPAC has a hierarchical porous structure and exhibits a high specific surface area (2104 m2 g-1) and a large pore volume (1.29 cm3 g-1). Its average pore size is 2.4 nm. The porous carbon-encapsulated sulfur composites were fabricated by a simple melt-diffusion method. The result of electrochemical measurement indicates that the HPAC/S electrode delivered a high initial discharge capacity of 1274 mAh g-1 at 0.05C. The discharge capacity of 465 mAh g-1 and the coulomb efficiency of over 96% were obtained after 50 cycles at 0.5C. Moreover, the HPAC/S electrode still retain a discharge capacity of 392 mA h g-1 after 100 cycles at a high rate of 1C.
Si-O-C Composites Prepared By Electrodeposition on CNTs/Cu or Carbon Paper Substrate and Electrochemical Performance for Lithium Ion Battery
Authors: Ahn Seongki , Jeong Moongook , Nara Hiroki , Yokoshima Tokihiko , Momma Toshiyuki , Osaka Tetsuya
Published: February 2020

Silicon have been attracted as promising anode material because of its higher theoretical capacity than commercial graphite (silicon: 4200 mA h g-1, graphite: 372 mA h g-1). We have been reported the novel Si-O-C composite as anode for lithium secondary batteries with high discharge capacity around of 1045 mA h (g of Si)-1 at 2000th cycle and 842 mA h (g of Si)-1 with outstanding cycle ability over 7200 cycles. Nevertheless, it is not easy to increase the thickness of Si-O-C composite for higher areal capacity due to its weak adhesion strength between Si-O-C with current corrector. To solve this problem, we reported the nickel micro-nanocones hierarchical structured (MHS) substrate and carbon nanotubes (CNTs) covered Cu substrate, and Si-O-C was deposited on those of current collectors, resulting in improved areal capacity and deposited Si amounts, 600 mA h cm-1 with Si-O-C deposited on MHS substrate and enhanced deposited Si amounts up to 16.7 % by CNTs/Cu substrate.

 In this research, the Si-O-C deposited on to CNTs/Cu substrate was used as anode for full-cell test with LiCoO2 (LCO) cathode. The loading amounts of LCO and Si-O-C were controlled to find optimum loading amounts for good-balanced LCO//Si-O-C full cell. Besides, to enhance the areal capacity, carbon paper (CP) which has three-dimensional structure was used as current collector. The Si-O-C/CP was prepared by electrodeposition with two kinds of electrolytes, in PC and EC/DEC bath. Material and electrochemical properties of Si-O-C/CP was measured by FE-SEM, raman spectrum, inductively coupled plasma, and charge/discharge test by half-cell.

Acknowledgements

This work was partly supported by “Advanced Low Carbon Technology Research and Development Program, Specially Promoted Research for Innovative Next Generation Batteries (ALCA-SPRING)” from Japan Science and Technology Agency (JST), Japan.

References

[1] M. Agostini, J.Hassoun, J. Liu, M. Jeong, H. Nara, T. Momma, T. Osaka, Y. Sun, and B. Scrosati, ACS Appl. Mater. Interfaces 6, 10924-10928 (2014).

[2] H. Nara, T. Yokoshima, T. Momma and T. Osaka, Energy Environ. Sci., 5, 6500 (2012).

[3] 22. T. Hang, H. Nara, T. Yokoshima, T. Momma, and T. Osaka, J. Power. Sources, 222, 503-509 (2013).

Figure 1
Preparation of High Surface Area-Activated Graphene Via Chemical Activation and Thermal Synthesis for Possible Applications on Lithium-Ion Batteries
Authors: Hsieh Cheng-Che , Liu Wei-Ren
Published: February 2020

A novel method to synthesize highly porous activated reduced graphene oxide via three-step synthesis is developed in this research. The initial step includes the chemical activation of reduced graphene oxide (RGO) by varying the concentrations of KOH. The resulting chemically activated RGO are subjected to hydrothermal method. The samples are dried and annealed at various temperatures and time. The KOH concentration, hydrothermal temperature and synthesis time, and annealing time and temperature all play a crucial role on the porosity of the graphene. It was found that without the hydrothermal synthesis, graphene exhibited a lower porosity. This can be possibly ascribed to the diffusion rate of KOH during the hydrothermal synthesis. Based on the SEM images, the pore size of the of graphene ranges from 1um - 500 nm. The high porosity of the graphene presents a potential application on Lithium ion batteries (LIBs) anode. Commercially available LIBs are based on graphitic anode However, graphite has a low theoretical capacity of 372 mAhg-1 and it suffers from volume expansion and shrinkage of carbon materials during Li+ ions intercalation/de-intercalation. The high porosity of the as-synthesized graphene could provide a better diffusion of Li+ ions in the anode inhibiting the volume expansion and cracks on the surface of the anode. Moreover, it can be further applied on various electrochemistry applications.
Cobalt Ferrite Nanoparticles Anchored on Functionalized Graphene Oxide for High Performance Lithium Ion Battery
Authors: Zhao Xianmin , Han Qiaofeng , Fu Yongsheng
Published: February 2020

Today, owing to long-term stability, high-energy density and safety, rechargeable lithium ion batteries have been used in many portable electronic devices. Unfortunately, the commercial graphite anode materials cannot meet the rapidly increasing demand of electric vehicles, hybrid electric vehicle and advanced energy storage devices. Attractively, due to the superior theoretical speciﬁc capacities, wide abundance and low cost, spinel structured ferrites (MFe2O4) stand out from various novel anode materials for next-generation LIBs. However, the application of MFe2O4electrodes was restricted by the enormous volume changes during the process of lithium insertion/extraction and low intrinsic electronic conductivity, which resulting in poor cycling stability and rate capability. Enormous efforts has been done to enhanced the stability and electronic conductivity, supporting on the graphene oxide as one of the most effective methods draws large attention, compared with carbon nanotubes, carbon black and carbon coating.

In this present work, graphene oxide was functionalized by piperazine (PG) to enhance the surface properties and the wettability. The ternary nanocomposites was synthesized through reflux process and subsequent hydrothermal treatment. The as-obtained CoFe2O4/PG nanocomposites delivered an excellent reversible capacity of 1050 mAh g-1 at the current density of 100 mA g-1 after 50 cycles. Even at a large current density of 1000 mA g−1, a reversible capacity of 720.8 mA h g−1 can still be retained. The outstanding cycling performance and rate capability can be contributed to the stability, predominant electroconductibility and favourable surface wettability of the functionalized graphene oxide, and the remarkable synergistic effect between CoFe2O4 nanoparticles and functionalized graphene oxide sheets.
Nickel Oxalate Dihydrate Nanorods Attached to Reduced Graphene Oxide Sheets As a High Capacity Anode for Rechargeable Lithium Batteries
Authors: Myung Seung-Taek , Jo Chang Heum , Yoon Chong seung , Yashiro Hitoshi , Sun Yang-Kook
Published: February 2020

In the search for high capacity anode materials, a facile hydrothermal route has been developed to synthesize phase-pure NiC2O4·2H2O nanorods, which were crystallized to orthorhombic structure without using templates. To ensure the electric conductivity of the nanorods, the produced NiC2O4·2H2O nanorods were attached to reduced graphene oxide sheets via self-assembly layer-by-layer processes utilizing the electrostatic adsorption that occurs in a poly(diallyldimethylammonium chloride) solution. High electric conductivity aided by the presence of reduced graphene oxide (rGO) significantly improved the electrochemical properties: 933 mAh g-1 for the charge capacity (oxidation), which showed 87.5% efficiency at the first cycle with its retention approximately 85% for 100 cycles, and 586 mAh g-1 at 10 C-rates (10 A g-1) for the NiC2O4·2H2O/rGO electrode were measured. We determined the details of the lithium storage processes involved with the conversion reaction, which were fairly reversible via a transformation to Ni metal accompanied by the formation of a lithium oxalate compound on discharge (reduction) and restoration to the original NiC2O4·2H2O on charge (oxidation); this was confirmed via X-ray diffraction, transmission electron microscopy, X-ray photoelectron microscopy, and time-of-flight secondary ion mass spectroscopy. We believe that the high rate capacity and rechargeability upon cycling are a result of the unique features of the highly crystalline NiC2O4·2H2O nanorods assisted by conducting rGOs.