bluuebunny/crossref_metadata_2025_split huggingface dataset:
III-V Semiconductors for Solar Vanadium Redox Flow Battery
Authors: Wang Peng , Parkinson Bruce A 
Published: February 2020

The intermittent nature of renewable energy from wind and solar sources requires effective energy storage systems. Even though solar energy storage can be realized in the form of hydrogen gas by photoelectrochemical reaction, hydrogen is a very low-density gas requiring high-end technology for storage and transport. The low quantum yield is also far below commercialized value, which makes it difficult for large-scale application. The vanadium redox flow battery(VRB) is a true redox flow battery, which combines electrochemical conversion and storage via reduction and oxidation reactions of vanadium redox couples, V(II)/V(III) in the negative half-cell and V(IV)/V(V) in the positive half-cell.1-3 With the same active vanadium species in both electrolytes, it overcomes cross contamination problem. Due to its low cost, high capacity, high charge-discharge efficiency, and long life cycles, VRB has attracted extensive research focus.
The solar VRB allows photoelectrodes to convert solar energy into electrochemical energy and direct storage of energy in positive and negative electrolyte containing V(IV)/V(V) and V(II)/V(III) redox couples, respectively. Gallium phosphide with a band gap of 2.26 eV, meets the requirement of optimal solar energy conversion efficiency in photoelectrochemical or photoelectrolysis cells.4 Our work demonstrated that photoredox reactions of vanadium electrolyte occurred on gallium phosphide under sunlight, indicating the promising use of gallium phosphide as photoactive electrodes for solar VRB. A thin amorphous TiO2 layer deposited on top of gallium phosphide by atomic layer deposition(ALD) was found beneficial to improve the long-term stability of gallium phosphide in an acidic medium, as well as facilitate electron/hole transfer on semiconductor/electrolyte interface. Thus, solar VRB would offer a promising approach for solar energy harvest, conversion and storage.
(1) Sum, E.; Skyllas-Kazacos, M. Journal of Power Sources 1985, 15, 179–190.
(2) Skyllas Kazacos, M.; Kazacos, G.; Poon, G.; Verseema, H. International Journal of Energy Research 2010, 34, 182–189.
(3) Noack, J.; Roznyatovskaya, N.; Herr, T.; Fischer, P. Angewandte Chemie International Edition 2015, 54, 9776–9809.
(4) Standing, A.; Assali, S.; Gao, L.; Verheijen, M. A.; van Dam, D.; Cui, Y.; Notten, P. H. L.; Haverkort, J. E. M.; Bakkers, E. P. A. M. Nature Communication 2015, 6, 7824.
The Effect of Contact Resistance during Nail Penetration of Commercial Automotive Lithium-Ion Cells
Authors: Abaza Ahmed 
Published: February 2020

Nail penetration is an abuse test that is part of most automotive safety test standards, e.g. the Society of Automotive Engineers’ SAE J2464. The main purpose of nail penetration is to test how batteries can withstand two failure mechanisms; internal short circuits and physical damage such as in the case of road accidents.
In this research, nails with varying diameters and materials were used to carry out penetration tests on commercial 15 Ah automotive Lithium-ion pouch cells. The voltage and temperature profiles of the cells during penetration were recorded. The data shows significant variability between tests with the same experimental conditions (nail properties, ambient temperature and cell type). It is proposed that the variability is due to the varying way the nail interacts with the penetrated layers of the cell. Therefore, the contact resistance between the bilayers of the cell and the nail varies between each test.
Contact resistance cannot be readily measured in nail penetration tests. In order to understand if the contact resistance is indeed the source of variability, an external short-circuit experiment has been conducted. Different shunt resistors were used to model and represent the contact resistance and this is presented.
Non-Isothermal Electrochemical Model for Low Temperature Operation of Linca Battery
Authors: Basu Suman , Hariharan Krishnan S , Kolake Subramanyya Mayya , Song Taewon 
Published: February 2020

Failure of Li-ion battery at low temperature continues to be one of the bottlenecks towards large scale commercialization of electric vehicles. Due to its high energy density, nickel-cobalt-aluminum (NCA) has gained favor as cathode material. However, not much has been reported about that low temperature performance of these cathodes. Experimental results showed that at low temperature (≤273K), the discharge voltage show effects of additional physical processes. A standard pseudo two-dimensional (P2D) electrochemical model may not be enough to adequately capture these behavior1.
At low temperature, Li-ion cells may exhibit Li-plating at anode, pseudo-capacitance at the electrode surfaces and sharp voltage drop due to increased electrolyte transport resistance, leading to cell failure. On the other hand voltage recovery due to self-heating has also been reported. Similar mechanisms have been implemented in Li-ion cells with NCM chemistry operating at low temperature2. Li-plating during charging at low temperature result in increased voltage during discharge as Li-plated over anode offer zero potential. When discharged at high rate and low temperature, the voltage shows sharp drop followed by a recovery and finally a gradual drop up to the cut off voltage. Heat generation, inherent to the high discharge rate, causes self-heating of the cell which in turn reduces the transport resistances and resulting in eventual voltage recovery. These mechanisms have been implemented over the base electrochemical-thermal model1 and validated against experiments (Fig.1).
References:

S. Basu et al., J. Power Sources 283 (2015) 132-150

Y. Ji, Y. Zhang, C-Y. Wang, J. Electrochem. Soc., 160 (4) A636-A649 (2013)

Figure 1
3D Imaging and in-Operando X-Ray Tomography Study of Lithiation Induced Delamination and Cracking of Si Based Anodes for Lithium Ion Batteries
Authors: Tariq Farid , Yufit Vladimir , Kareh Kristina , Lee Pui-kit , Yu Dennis Y.W. , Eastwood David S , Lee Peter D , Biton Moshiel , Merla Yu , Peled Emanuel , Golodnitsky Diana , Brandon Nigel P. 
Published: February 2020

It is becoming increasingly important to meet rising demands for energy storage, supply and portability. An ability to directly image and manufacture electrochemical devices such as batteries, in 3D, at high resolutions will help address these demands. The influence of microstructure on electrode behaviour can be tracked through 3D imaging, ultimately enabling intelligently designed electrodes to be printed or additively manufactured.
Tomographic techniques allow for direct 3D imaging and characterisation of complex multi-phase microstructures which are inadequately described in 2D. The performance of battery electrodes is dependent on their inherent nano/micro scale structures where important reactions occur. Microstructural differences in mechanical, electrochemical or transport behaviour at fine length scales ultimately influences cell and pack level performance. Additionally, during processing or operation, microstructural evolution may degrade electrochemical performance.
Here we utilise X-ray tomographic techniques to probe in 3D, silicon based battery structures at high resolutions. The advanced 3D quantification of complex electrode shapes, structures and morphology facilitates a detailed understanding of cell level behaviour. Furthermore, we directly image and track in-operando interfacial and microstructural changes during operation and dynamic failure (Figure 1). In doing so this provides important insights for future electrode design, enabling performance optimised structures to be created and understanding the sources of performance degradation.

Figure 1
In-Situ TEM Analysis of Ink-Jet Printed MnO2-Graphene for Supercapacitor Electrodes
Authors: McKeon Lorcan , Long Edmund , Coelho João , Zhang Chuanfang , Park Sang Hoon , Coull Richard , Shmelov Aleksey , Nicolosi Valeria 
Published: February 2020

Supercapacitors composed of nano-layered material electrodes represent a new generation of energy storage technology. Understanding and analyzing the mechanism of how the electrode material changes and degrades during the charge and discharge process is fundamental to maximizing the efficiency of supercapacitors.
The primary objective of this body of work was to develop a method whereby the electrode-electrolyte interface of a supercapacitor could be analyzed by real time in-situ TEM imaging during the charge-discharge process. This experimental approach combines advanced microscopy techniques and electrochemical testing. This approach is in the preliminary stages of experimental development, with very few major published works exploring the specific use of this technique. First, an effective method for repeatable deposition of our layered electrode material was developed, using inkjet printing methods. Our selected active material, MnO2-Graphene nanoflakes suspended in Isopropanol was used as our material ink for printing. This suspension was printed onto a specialized electrochemistry TEM chip, featuring Au electrodes and a transparent SiN2 window for TEM viewing. A low concentration dispersion of 0.5 mg mL-1 was first used to optimize the printing process and to find the printing parameters that minimized the spreading of the printed line. Having fully optimized the printing process, a high concentration 10 mg mL-1 suspension of MnO2-Graphene was used to deposit the working electrodes of our micro electrochemical cell.
This cell was tested with a range of potential windows and multiple material deposition thicknesses. In most potential ranges, responses from the active material were difficult to observe due to the noise created by the inherent double layer capacitance of the Au electrode. Higher amounts of deposited material produced slightly higher responses but were for the most part unobservable above the aforementioned noise. These high layer depositions were also electron opaque. During in-situ TEM CV testing of these cells, prominent dendritic growth outward from our electrodes were observed.
Higher CV responses ex-situ could be achieved with higher amounts of deposited active material, overcoming the noise generated by the Au-electrolyte reactions. For in-situ tests, morphological changes could be observed with lower amounts of material, so that the individual flakes of the Solid-Electrolyte interface can be resolved via TEM analysis.
Supercapacitive Properties of the Electrodeposited Layered Electrodes of Ruthenium Oxide and Polyaniline
Authors: Kim Kwang Man , Lee Young-Gi , Kim Jumi , Kim Ju Young , Ko Jang Myoun 
Published: February 2020

Layered electrodes of electrodeposited RuO2 (eRuO2) and polyaniline (ePAn) are prepared on a platinum substrate to yield ePAn-on-eRuO2 and eRuO2-on-ePAn electrodes and their supercapacitive properties are investigated. The eRuO2 electrode forms a compact stratified structure with nearly flat surfaces by electrodeposition from a RuCl3×3H2O-based solution, whereas the ePAn electrode forms densely connected particles or particle aggregates by the electrodeposition from aniline solution. In the scan rate range of 20-1000 mV s-1, specific capacitance (810-575 F g-1) of ePAn-on-eRuO2 electrode is superior by the higher probability to occur redox reaction and proton diffusion due to particulate surface and inner pores of the upper layer (ePAn), respectively. In contrast, the eRuO2-on-ePAn electrode loses the specific capacity (680-550 F g-1) but achieves higher capacity retention ratio (81%) by flat compact surface of the upper layer (eRuO2).
Fig. Schematic diagrams of (a) eRuO2, (b) ePAn, (c) ePAn-on-eRuO2, and (d) eRuO2-on-ePAn electrodes.

Figure 1
Hybrid Composite Electrodes for Supercapasitors Prepared By Simple Routes
Authors: Mokkelbost Tommy , Hanetho Sidsel Meli , Barnett Alejandro Oyarce , Tolchard Julian Richard , Svensson Ann Mari , Montemor Fatima 
Published: February 2020

Supercapacitors, which can store energy by a combination of electrostatic (double layer capacitance) and electrochemical (pseudocapacitance) storage of electrical energy, are an important energy storage device applicable for a variety of uses and technologies, especially in applications which requires rapid charge/discharge cycles and several thousands of cycles, e.g. short term energy storage and high power delivery. The asymmetric electrode configuration which allows for the use of aqueous electrolytes are a promising route to low-cost and environmentally friendly supercapacitors without compromising power and energy density.
Here we present a novel approach based on easy synthesis methods to prepare hybrid electrode materials consisting of mixed transition metal oxides for the redox contribution together with carbonaceous materials contributing to the double layer response. The synthesis methods used are possible to scale up and results in nanosized, high surface area hybrid electrode materials. Three different methods have been selected resulting in significant different morphologies and characteristics. The electrode materials have been characterized by standard physical techniques, e.g. SEM, TEM, EDX and XRD. To prepare final electrode materials, inks using PTFE, ketjen black and H2O/isopropanol, was spray coated on carbon paper with a loading of approximately 1 mg/cm2. The electrodes were tested for electrochemical performance as capacitors, by use of techniques such as cyclic voltammetry and charge and discharge curves, as a function of electrode composition, time and type of aqueous based electrolyte, and compared with hybrid electrodes fabricated by e.g. electrodeposition methods.
Preliminary results have shown that it is possible to produced hybrid materials through cheap and flexible processes in aqueous electrolytes.
Controllable Growth and Ultrasensitive Molecule Detection of Large-Area Doped Graphene
Authors: Lyu Ruitao 
Published: February 2020

Substitutional doping with heteroatoms is a very efficient way to tailor the electrical and chemical properties of graphene. Due to the size limitation, the most adjacent neighbors of carbon in the Periodic Table of the Elements, i.e. boron and nitrogen, are the best choice for achieving substitutional doping due to their similar sizes when compared to carbon. Accordingly, both experimental and theoretical research on N-doped graphene have been extensively carried out so far. However, the experimental reports on large-area Si-doped and B-doped graphene sheets are still quite few up to now. In this contribution, we summarize our recent progress on controllable synthesis of centimeter size, high-crystallinity doped graphene sheets. Their excellent sensing properties are demonstrated by using gaseous (e.g. NO2, NH3)1 and liquid molecules (e.g. crystal violet, rhodamine B and methylene blue)2 as probes. Our results will open up new avenues for developing high-performance sensors able to detect trace amount of molecules. In addition, other new fascinating properties can be exploited based on as-synthesized large-area doped graphene sheets.
References
1. Lv, R. et al. Ultrasensitive gas detection of large-area boron-doped graphene. PNAS
112, 14527-14532 (2015).
2. Lv, R. et al. Large-Area Si-Doped Graphene: Controllable Synthesis and Enhanced Molecular Sensing. Adv. Mater.
26, 7593-7599 (2014).
Macroscale Superlubricity Enabled By Ensembles of Graphene on Diamond Nanoscrolls
Authors: Sankaranarayanan Subramanian K. R. S. 
Published: February 2020

The power of modern supercomputers together with the availability of highly scalable atomistic simulation codes have begun to revolutionize the modeling and computational analysis of materials. An enticing illustration of the same comes from our recent work where large-scale molecular dynamics (MD) simulations performed on Argonne’s supercomputer Mira closely coupled with experimentation led to a breakthrough in the field of tribology.1 An elusive phenomenon termed “Macroscale superlubricity” which refers to an extremely low friction state was shown to originate from an intriguing nanomechanical phenomenon: graphene patches wrap around nm sized diamond particles to form nanoscrolls that have significantly reduced contact area to an underlying surface. Atomistic simulations elucidated the overall mechanism and explained the mesoscopic link between the nanoscale mechanics and macroscale experimental observations. Given our recent success with nano-lubricants1, we will focus on accurately capturing ensemble effects across tribological interfaces using some representative lubricant materials (2-D materials, nanoparticles) and their combinations for different types of environments and operating conditions. This talk also will include brief discussion on our ongoing efforts towards development of a new class of force fields to enable high-fidelity large scale dynamical and statistical simulations of tribo-interfaces, properties and functionalities of new lubricants, as well as pathways and mechanisms of their in operando synthesis and assembly.
References:

Berman et al. Science, 348, 6239, 1118 (2015)
RCC Inspired Synthesis of Graphene - Carbon Nanotube Hybrid for Use in Flexible Electronics
Authors: M S Brahma Teja , B Siva Kumar 
Published: February 2020

Graphene with its unique electronic and structural qualities has become an important material for use in various devices as a substrate for catalyst loading. Graphene hybrids have emerged as a new platform for various applications such as flexible photovoltaics and other flexible electronics. Key features for a material to be used include stability, rigidity, flexibility and conductivity. A self assembled hybrid of Graphene and CNTs just like laying Reinforced Concrete Cement, is envisaged to be the an ideal substrate. Also in view of growing industrial demands, a scalable method has been developed to obtain the conducting films.

Figure 1
Spectroscopic Analysis of Nitrogen-Doped Ultrananocrystalline Diamond/Hydrogenated Amorphous Carbon Composite Films Prepared By Coaxial Arc Plasma Deposition
Authors: Gima Hiroki , Zkria Abdelrahman , Yoshitake Tsuyoshi 
Published: February 2020

Ultrananocrystalline diamond/hydrogenated amorphous carbon composite (UNCD/a-C:H) is a new candidate carbon semiconductor applicable to electrical devices. It has been investigated that nitrogen-doping for diamond is ineffective for realizing n-type conduction at room temperature, because nitrogen form a deep donor level of 1.7 eV below the bottom of a conduction band in diamond. For a-C:H, n-type conduction is realized by nitrogen doping, however it is difficult for the carrier density to be controlled widely. On the other hand, it has been reported that nitrogen doping is effective for UNCD/a-C:H prepared by chemical vapor deposition (CVD) and pulsed laser deposition (PLD)1), 2), the doping mechanism for UNCD/a-C:H seems to differ from those for diamond and a-C:H. In this study, UNCD/a-C:H films were prepared by coaxial arc plasma deposition (CAPD) with nitrogen atmosphere and the effects of the nitrogen doping on the UNCD crystallite formation were structurally investigated. X-ray photoemission spectra (XPS), which were measured with MgKα line, of the UNCD/a-C:H films prepared at different inflow ratio of nitrogen and hydrogen (IN/H
). N1s peaks strengthened with an increase in the IN/H
, which evidently indicates that the nitrogen content in the film increased with the IN/H
. The nitrogen contents of the films deposited at IN/H
of 0.25, 0.5, 1.0 and 1.5 were estimated to be 3, 5, 6 and 8 at. %, respectively. Near-edge X-ray absorption fine structure (NEXAFS), spectral shape of the nitrogen-doped films different from the undoped film were obtained. By increasing the doping amount, the intensity of the π*C=N increased, while the intensity of the σ*C-C is decreased. Which refers to strengthen in sp2 bonds and weaken in sp3 bonds. Furthermore, increasing the electrical conductivity by increasing the nitrogen-doping amount can be ascribed to contribute of sp2bonds. The details will be reported at the conference.
1) Dai, et al.: Phys. Rev. B 71, 075421 (2005).
2) T. Yoshitake, et al.: Jpn. J. Appl. Phys 49, 015503 (2010).
Galvanic Corrosion Studies of Aluminum Coupled to Non-Passivating and Passivating Alloys
Authors: Quiambao Kathleen 
Published: February 2020

Research has been conducted to study the corrosion behavior of galvanic couples in order to develop a thorough understanding of the galvanic corrosion of aluminum (i.e., 6061-T6 Al) in atmospheric environments when it is coupled to more noble non-passivating metals (i.e., silver and copper), passivating metals (i.e., Ti-6Al-4V and 316 stainless steel), and non-passivating active metals (i.e., mild steel and Mg AZ31B). The couples were subjected to atmospheric exposure in marine, volcanic, and rainforest environments, as well as the chloride-containing GM 9540 accelerated corrosion test. The purpose of the research project is to obtain a scientific understanding of the galvanic corrosion mechanisms and quantitative metrics for aluminum so that the data can be used to predict the effects of galvanic corrosion in multiple component systems. The determination of overall corrosion damage during atmospheric exposure is complicated because non-passivating, noble metals (e.g., Cu and Ag) can contaminate the aluminum surface and change the local-action corrosion rates; whereas, passivating metals (e.g., 316 stainless steel and Ti-6Al-4V) are less likely to contaminate the Al surface. In this experiment, corrosion rate was determined by measuring galvanic corrosion currents and total corrosion was measured via mass-loss data. The differing corrosion rates between each atmospheric condition can be attributed to environmental parameters such as specimen temperature, time of wetness, chloride deposition, acid rain, etc. Potentiodynamic polarization experiments were also conducted to study the mechanisms of galvanic corrosion for the couples described above.