bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tubular TiO2 Structures Towards Biocompatible Microsupercapacitors
Authors: Salari Maryam , Aboutalebi Seyed Hamed , Ekladious Iriny , Jalili Rouhollah , Konstantinov Konstantin , Liu Hua Kun , Grinstaff Mark W 
Published: February 2020

Self-organized tubular metal oxide nanostructures, synthesized through straightforward and efficient techniques, have resulted in many breakthroughs yet are underutilized in the energy and microdevice field. Here we demonstrate the fabrication and characterization of unique biocompatible energy storage devices that use self-assembled titanium dioxide (TiO2) and a physiological fluid such as PBS as the electrolyte, without any need of toxic conventional acidic or alkaline electrolytes. Achieving high capacitance through the use of a neutral aqueous electrolyte, combined with the biocompatibility of TiO2 and Ti films opens up new avenues for the investigation of these materials for energy harvesting applications in biological media. We also describe unadulterated anodized TiO2 with higher volumetric capacitance (220 F cm-3) and energy density (5.12 mWh cm-3) values compared to the conventional carbon based micro-supercapacitor devices.
Figure 1. (a) Cyclic performance of TNTA device obtained by CV test at scan rate of 20 mVs-1 along with the 2nd and 2000th cycles of the CV performances in two electrolytes (inset), (b) In-vitro biocompatibility of TNTAs; NIH 3T3 cells exposed to TNTAs for 24 hours did not exhibit a decrease in cell viability compared to untreated cells.

Figure 1
Laser-Structured Electrodes for Lithium-Ion Batteries
Authors: Li Jianlin , Smyrek Peter , Wood Marissa , Zheng Yijing , Sheng Yangping , Rakebrandt Jan-Hendric , Du Zhijia , Pfleging Wilhelm , Wood David L 
Published: February 2020

Insufficient energy density is one of the barriers for widespread application of lithium-ion batteries (LIBs). Increasing energy density relies on developing novel active materials with higher energy density and/or increasing the active material ratio via electrode engineering [1].
One natural strategy is to increase the energy density by increasing the electrode thickness, which reduces the fraction of some inactive components such as current collectors and separators. However, thick electrodes suffer from electrolyte depletion under high discharge rates and low power density. As a result, electrodes are divided into two categories—thin electrodes (ca. 50 µm) for high power application and thick electrode (> 100 µm) for high energy application [2]. This work reports a design in thick electrodes with 3D micro-structures enabled by laser processing, which minimizes the electrode tortuosity and improves the lithium ion diffusion kinetics. This novel design enables high energy and high power densities for LIBs.
References:
[1] Z. Du, D.L. Wood, C. Daniel, S. Kalnaus, J. Li, Journal of Applied Electrochemistry 47 (3), (2017) 405-415
[2] P. Smyrek, J. Proll, H. J. Seifert, and W. Pfleging, Journal of the Electrochemical Society, 163 (2), (2016) A19-26.
Acknowledgements
This research at Oak Ridge National Laboratory, managed by UT Battelle, LLC, for the U.S. Department of Energy (DOE) under contract DE-AC05-00OR22725, was sponsored by the Office of Energy Efficiency and Renewable Energy (EERE) Vehicle Technologies Office(VTO) (Deputy Director: David Howell) Applied Battery Research subprogram (Program Manager: Peter Faguy).
This work at Karlsruhe Institute of Technology (KIT) received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement no. 644971. Finally, the support for laser materials processing by the Karlsruhe Nano Micro Facility (KNMF, http://www.knmf.kit.edu/) a Helmholtz research infrastructure at KIT is gratefully acknowledged.
Alignment and Size Control of TiO2(B) for Fast Lithium Storage
Authors: Sugimoto Wataru , Yoshida Tomohiro , Tanaka Ryo , Makino Sho , Ayato Yusuke , Mochizuki Dai 
Published: February 2020

TiO2(B) has attracted much interest as a fast and safe anode for lithium ion batteries as well as lithium ion capacitors owing to its high theoretical capacity (335 mAh g-1), fast Li intercalation/de-intercalation properties and favorable electrode potential. TiO2(B) can be synthesized by thermal treatment of layered titanate. We have shown that TiO2(B) thin films can be prepared by utilizing electrophoretic deposition (EPD) of TiO2 nanosheets [1]. Such methods afford TiO2(B) film with the (0k0) planes lying perpendicular to the substrate.
In this study, the influence of the orientational structure (horizontal, vertical, random alignment) on the kinetics of Li+ storage in TiO2(B) was studied by fabricating TiO2(B) electrodes with the same mass loading by different orientation.
Vertically aligned TiO2(B) films were prepared by a combination of EPD and freeze-drying. Randmoly stacked TiO2(B) films was prepared by flocculation of nanosheets. Furthermore, the effect of the TiO2(B) size was studied by using TiO2 nanosheets with different lateral size. Electrochemical lithiation/de-lithiation studied in 1 M LiPF6/EC-DEC by cyclic voltammetry and galvanostatic charge/discharge revealed that the orientation of TiO2(B) had a large influence on Li+ storage kinetics. Perpendicularly aligned TiO2(B) showed much faster Li+ intercalation/de-intercalation behavior compared to vertically aligned TiO2(B) with the same mass loading. Randomly stacked TiO2(B) possesed similar performance to vertically aligned TiO2(B). High power capability was further improved by using smaller-sized TiO2(B).
[1] W. Sugimoto, O. Terabayashi, Y. Murakami, Y. Takasu, J. Mater. Chem., 12, 3814-3818 (2002).
Combining Battery-like and Pseudocapacitive Charge Storage in 3D MnOx–Carbon Electrode Architectures for Zinc-Ion Cells
Authors: Ko Jesse S. , Sassin Megan B. , Rolison Debra R. , Long Jeffrey W. 
Published: February 2020

The ability of manganese oxides to exhibit charge-storage behavior characteristic of either batteries or electrochemical capacitors (ECs) offers an intriguing opportunity to design electrode materials that innately deliver both high power and high capacity. We previously demonstrated that lamellar birnessite-type MnOx, when expressed in carbon nanofoam–based electrode architectures (MnOx@CNF), amplifies charge storage by pseudocapacitance in aqueous electrolytes (e.g., Na2SO4; Li2SO4). Herein, we extend the functionality of these established electrode materials by varying the ionic composition of the electrolyte in which they are cycled. For example, cycling MnOx/C nanofoam electrodes in aqueous 1 M ZnSO4 yields battery-like voltammetric features reminiscent of those previously reported for “rechargeable Zn-ion batteries.” When cycling in mixed Na2SO4:ZnSO4 electrolytes, we retain Zn2+ redox peaks, but now superimposed on a pseudocapacitive background arising from the presence of Na2SO4. The Zn2+ redox provides high capacity (up to 230 mAh g–1 normalized to MnOx) at low rates (<5 mV s–1), while pseudocapacitance mechanisms take over at high rates to mitigate the effects of slow kinetics for Zn2+ insertion. Fundamental electrochemical properties are established using a three-electrode half-cell configuration. We apply peak-current kinetic analyses (for CV data) and AC impedance to deconvolve the complex mechanisms that give rise to battery-like and pseudocapacitive charge-storage features. On the basis of three-electrode studies, we down-select electrolyte compositions for testing MnOx@CNF, paired against Zn metal, in two-electrode Swagelok cells that are subjected to galvanostatic cycling at challenging C-rates (1C–20C).
Redox-Active Organic Positive Electrodes for Li- and Na-Ion Capacitors
Authors: Liu Tianyuan , Lee Byeongyong , Park Jinho , Lee Seung Woo 
Published: February 2020

Li-ion capacitors employ capacitive positive electrodes from electrochemical capacitors (ECs) and intercalation negative electrodes from Li-ion batteries (LIBs), bridging the performance gap between ECs and LIBs. However, the low capacity of capacitive positive electrodes limits the energy density of the Li-ion capacitors. Incorporating pseudocapacitance (surface redox reaction) into the carbon materials is a promising strategy to enhance the capacity of the carbon-based positive electrodes. We have been investigating the redox reactions of various organic materials with Li- and Na-ions for hybrid capacitor applications. We have revealed that the organic electrodes, which are prepared from pyrene derivatives,1 hydrothermally synthesized carbon from glucose,2 and polymerized dopamine,3 have redox reactions with Li- and (or) Na- ions. In this study, we further reveal that the organic electrodes can store high capacities in both Li- and Na-cells in the high voltage region by utilizing the redox reactions between oxygen functional groups and metal ions. Finally, we demonstrate the high-performance Li-ion capacitors by combining the organic positive electrode and high-energy battery negative electrode.
References
1. J. C. Bachman, R. Kavian, D. J. Graham, D. Y. Kim, S. Noda, D. G. Nocera, Y. Shao-Horn and S. W. Lee, Nature Communications, 6:7040 (2015).
2. T. Y. Liu, R. Kavian, Z. M. Chen, S. S. Cruz, S. Noda and S. W. Lee, Nanoscale, 8, 3671 (2016).
3. T. Liu, K. C. Kim, B. Lee, Z. Chen, S. Noda, S. S. Jang and S. W. Lee, Energy & Environmental Science, 10, 205 (2017).
Hybrid Composite Electrodes for Asymmetric Full Cell Supercapacitors
Authors: Mokkelbost Tommy , Tolchard Julian Richard , Jayasayee Kaushik , Barnett Alejandro Oyarce , Hanetho Sidsel Meli , Svensson Ann Mari , Montemor M. F 
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 powder 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. Different methods have been selected which results 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 different loading to be able to balance a asymmetric cell. The electrodes were tested for electrochemical performance as capacitors, such as cyclic voltammetry and charge and discharge curves, as a function of electrode composition, time and type of water based electrolyte, and compared with e.g. electrodeposition. Some of the composite electrode demonstrated specific capacitances of 300 Fg-1. Asymmetric cells were prepared using electrodes of metal oxide/carbon and pure "capacitor grade" carbon with tailored loading for balancing the cell and mounted in a El-cell using aqueous electrolytes.
The project is funded through the m-ERA.net program and financial support from Research Council of Norway and Fundação para a Ciência e a Tecnologia is appreciated.
Pseudocapacitive Polycationic Oxides for Supercapacitors Operating in Aqueous Electrolytes
Authors: Crosnier Olivier , Goubard-Brétésché Nicolas , Buvat Gaëtan , Douard Camille , Iadecola Antonella , Favier Frederic , Brousse Thierry 
Published: February 2020

Electrochemical double-layer capacitors (EDLCs) represent the most important family of today’s commercially available Electrochemical Capacitors (ECs). Such systems store charges electrostatically in the electrochemical double-layer that arises from the separation of charges at the electrode / organic electrolyte interfaces when polarizing the electrodes, and exhibit an excellent cycling stability combined with fair gravimetric and volumetric energy densities. Other types of ECs use “pseudocapacitive” materials, i.e. materials that use fast and reversible surface redox (faradic) reactions to store energy. To combine the advantages of both organic EDLCs and aqueous symmetric systems, the design of aqueous asymmetric supercapacitors was proposed. These devices comprise either two pseudocapacitive materials, or a pseudocapacitive and a capacitive carbon-based material which exhibit complementary electroactive windows. As a result, operating cell voltages approaching 2 V can be obtained, leading to competitive energy densities without the disadvantages of using an organic electrolyte [1].
Both specific energy and power densities have to be increased and improving the volumetric capacitance of supercapacitors, which is one of the limiting factors of today’s stationary applications, is essential [2]. In order to meet those requirements, solid state chemistry is an extremely powerful tool to design new materials. Our strategy was based on the study of materials that are electrochemically active in aqueous media, with transition metals and/or high density elements, with the possibility to use low-temperature synthesis methods in order to get nanosized particles with high specific surface areas, and the possibility to have several redox couples that could be involved in the charge storage mechanism. Among the studied materials, our interest has focused on different materials such as transition metal oxides (MnO2, Fe3O4,…) and polycationic oxides MWO4 (M=Fe, Mn, Co,…) [3]. Synthesis conditions and materials characterizations of the electrodes and also of full devices will be detailed in the presentation, highlighting the crucial role of the electroactive elements, the crystallographic structure, and the morphology of the synthesized materials on their electrochemical performance.

J.W. Long et al., MRS Bulletin., 36, 513 (2011).

N. Goubard-Bretesché et al., Electrochem. Commun., 57, 61 (2015).

N. Goubard-Bretesché et al., Electrochim. Acta
206, 458 (2016).
Utilization of Engineered Iron Oxide and Industry Waste Red Mud in High Performance Supercapacitor
Authors: Bhattacharya Gourav , Roy Susanta Sinha 
Published: February 2020

Development of high performance energy storage materials is still an important topic to the researchers as there is a rapid depletion of non-renewable energy resources and a continuous demand for electrical power sources. In this work, at first, by utilizing electrochemical technique, supercapacitor behavior of a novel hybrid nanocomposite encompassed of engineered iron oxide (Fe3O4) nanoparticles and reduced graphene oxide (RGO) was investigated. The synergistic effect between the Fe3O4 and RGO components accomplished a high sp. capacitance (576 F g−1) a high energy storage density ( 75 W h kg−1 at a current density of 6 A g−1) and a promising long term stability [1]. The engineered coating not only enhances the pseudo-capacitive charge transfer process but also felicitates enhanced surface area which boosts double layer capacitance. Motivated by the above results, the potential use of red mud (an aluminum industrial waste material) as supercapacitor electrode was further explored. Red mud, a natural source of iron oxide (Fe2O3) was mechanically processed. The nanoparticle exhibits a promising energy density, a moderate specific capacitance and a remarkable cyclic stability, where ~ 98% of the initial capacitance was retained even after 5000 cycles for a high sp. current density (6 A g-1) (Fig. 1). This study shows that waste red mud can effectively be utilized in energy harvesting.

References

[1] Gourav Bhattacharya et al. RSC Advances 7.1 (2017): 327-335.

Figure 1
CVD Synthesis and Functionalization of Boron-Doped Graphene
Authors: Ion-Ebrasu Daniela , Enache Adrian , Enache Stanica , Soare Amalia , Carcadea Elena , Varlam Mihai , Stefanescu Ioan 
Published: February 2020

We report in this paper the development of Boron-doped Graphene via chemical vapor deposition (CVD) that can serve as an efficient metal-free electrocatalyst for hydrogen evolution reaction (HER) in both alkaline and acidic media. Graphene growth is carried out by the flow of methane and hydrogen gasses, and with a borazine precursor over Ni foil and foam substrates at atmospheric pressure. The characterization is performed with scanning electron microscopy (SEM/EDS) and Raman/AFM spectroscopy. Electrochemical characterization of HER is performed by cyclic voltammetry (CV) measurements in 1 M KOH and 1M H2SO4 respectively, at room temperature, and 10 mV s–1 scan rate. Electrochemical tests are performed with an in-house designed cell with 1 cm2 surface area. The catalytic activity towards the HER of catalysts is determined from Tafel plots obtained from galvanostatic current-voltage measurements.
Chemical Purification of Gd3N@C88 Metallofullerene Using Alcohols and Lewis Acids
Authors: Thompson Hannah R. , Stevenson Steven 
Published: February 2020

This project addresses the paucity of literature on trimetallic nitride fullerenes possessing carbon cages larger than C80. Herein, we present our chemical isolation of Gd3N@C88, which was selected based on the (1) few reports describing its fundamental chemistry and (2) curiosity of its candidacy as an effective MRI contrast agent. To date, MRI contrast agent development for metallic nitride fullerenes has focused on the more ubiquitous and smaller-cage Gd3N@C80 species. Excitement for Gd3N@C88 is predicated, in part, on the projected increased reactivity of its C88 cage. The higher reactivity could, in principle, allow more attached hydrophilic groups, which in turn would translate into better water-solubility and improved clearance from the body in biological systems. Prior to any application, though, the fundamental science must first be performed. We demonstrate that the unique chemical reactivity of Gd3N@C88 can be strategically manipulated into a separation strategy for its isolation from complex extract mixtures containing more than 50 different species of fullerene and metallofullerene contaminant species. We describe the use of amino alcohols and Lewis acids to obtain highly enriched samples of greater than 90% purity. For subsequent studies (e.g., medical) demanding a higher purity (>99%), the appropriate HPLC parameters and fraction collection are also discussed.
Effect of Tail Length of Surfactant-like Corrosion Inhibitors on Chemical Mechanical Planarization Slurry
Authors: Ho Lin-Chen , Tsai Wei-Wen , Lee Cheng-Bin , Hsu Yao-Hsin , Wang Jiun-Fang , Zhou Wenjia 
Published: February 2020

Integrated circuits (IC) are produced by deposition and modification of different dielectric and metal layers on a silicon wafer. Because of the continuing miniaturization of the device dimensions and the requirements of interconnecting an increasing number of devices on a chip, building multilevel interconnections on planarized levels has become an essential part of IC production. Chemical mechanical planarization (CMP) is a process of smoothing the dielectric and metal films in the process of integrated circuit fabrication with the combination of chemical and mechanical forces. For a metal CMP slurry, the key components and steps are as follows: 1. Oxidizing agent is added to the slurry to oxidize the metal surface. 2. Nano-scaled abrasives subsequently remove the dielectric and oxidized metal layer by mechanical force. 3. Inhibitors are added to prevent or minimize undesired corrosion thus controlling the surface quality.
A group of surfactant-like inhibitors have been investigated in this study. Their structures differed by the length of their hydrophobic tails (alkyl groups having 4 to 16 carbon atoms). The molecules were absorbed on metal wafer surface through hydrophilic head and the hydrophobic tail wriggled on top and around. Thus, adjusting the length of tail may change the behavior of the adsorbing layer on metal films, which provided a viable route to interrupt the interactions between slurry components and the metal surface. We found that adjusting the length of tail affected the CMP slurry properties (such as suppression of static etching rate, see Figure 1), longer tail lengths led to better etching inhibition, and also caused distinct modification on the surface of abrasive (mean particle size and zeta potential). Polishing performances including removal rates and topography were also affected by the tail length, but the results with various feature sizes were more complex due to the combined net effect of etching inhibition and modified abrasive properties. The tail length demonstrated an important role on slurry stability and polishing performance.
Figure 1. The decay of etching rates with inhibitors. The indicate-axis tail numbers designate the carbon atoms in hydrophobic tails.

Figure 1
Modelling Microstructural and Chemical Degradation of Ferritic Stainless Steels for SOFC Interconnects
Authors: Oum Melissa , Andrews James , Steinberger-Wilckens Robert 
Published: February 2020

Ferritic Fe-based (FeCrX) alloys forming a protective chromium oxide film are used for providing electrical interconnection in high temperature Solid Oxide Fuel Cells (SOFC) are susceptible to degradation mechanisms in the presence of high temperatures (>600oC), and humid air. These translate by the increase in interconnect electrical contact resistance and the formation of volatile chromium species causing poisoning of the adjacent cathode.

Modelling tools and techniques are increasingly becoming popular to gain better understanding of the degradation mechanisms that lead to the formation of volatile chromium species. This research work examines the oxidation behaviour of uncoated ferritic stainless steels system operated at temperature of 700oC in both wet (3% humidity) and dry conditions.

A model is presented based on the physical processes involved. The model is able to predict the weight gain of the samples upon oxidation, the oxide film thickness, the volatilization of chromium and the useable lifetime of interconnects based on chromium depletion. Parameter determination from standard experiments is discussed along with the physical and design insights from the model. Perhaps most importantly the model provides recommendations regarding accelerated testing of FeCrX interconnects and control of the Chromia film thickness.

Acknowledgements: This work was supported by the European FCH JU in project SCORED 2:0 under contract no. 325331 and the EPSRC.