bluuebunny/crossref_metadata_2025_split huggingface dataset:
Invsetigation on High Charge Density of States in Electrocheimcal Polymer Transistor
Authors: Lee Jiyoul 
Published: February 2020

Using temperature-dependent charge transport measurements, we investigated spectral density of states (DOS) in the bandgap of polythiophene thin-films under high carrier densities (< 3.5 x 10^20 cm-3) induced by electrochemical doping. The thermally activated charge transport indicates that the electrical currents in the polymer thin-film under high charge density state follows the Meyer-Neldel rule. The spectral DOS extracted from the electrolyte-gated polymer film lie in the range of 8.0 x 10^19 cm-3eV-1 ~ 8.0 x 10^21 cm-3eV-1, which are at least two orders of magnitude larger than the DOS extracted from the same polymer film at relatively low induced carrier densities by general oxide dielectrics. This is believed to result from the complete passivation of trap sites distributed in the polymer thin-film bulks by the high carrier density induced in the device. By using such a method, DOS distributions close to the intrinsic energy distribution of the polythiophenethin-film could be estimated.
Graphene Polyaniline/Polyoxometalate Hybrid As Cathode for Lithium Ion Batteries with Improved Lithium Storage Capacity
Authors: Diao Guowang 
Published: February 2020

Abstract: polyaniline/polyoxometalate nanospheres hybrid were synthesized via a facile interfacial polymerization method, and evaluated as a cathode material for lithium ion batteries. However, both polyoxometalate and polyaniline/polyoxometalate can be easily dissolved in LiPF6 eletroyte. In order to solve this problem，polyaniline/polyoxometalate nanospheres were first embedded into the interspaces of grapheme, leading to the formation 3D free-standing rGO@PANI/POM hybrid. The molecular cluster battery in which the RGO@PANI/PW12O34 hybrid was adopted as a cathode active material exhibited a higher battery capacity and stability than the PANI/ PW12O34 and the microcrystal polyoxometalate. The phosphotungstic acid polyanions not only exhibit a large theoretical capacity of about 260 mAh g−1, but also reduce the charge transfer resistance of electrode leading to the enhanced reversible capacity and rate capability.

Reference

[1] Liu, K.; Zheng, J. M.; Zhong, G. M.; Yang, Y. Poly(2,5-dihydroxy1,4-benzoquinonyl sulfide) (PDBS) as a Cathode Material for Lithium Ion Batteries. J. Mater. Chem. 2011, 5, 4125.
[2] Shao, L.; Jeon, J. W.; Lutkenhaus, J. L. Polyaniline/Vanadium Pentoxide Layer-by-Layer Electrodes for Energy Storage. Chem. Mater. 2012,24, 181.
[3] Zhang, L., Wu, H. B., & Lou, X. W. D. Iron-oxide-based advanced anode materials for lithium-ion Batteries . Advanced Energy Materials, 2014, 4, 1032.

ACKNOWLEDGEMENTS

This work was financially supported by the National Natural Science Foundation of China (Grant No. 21273195), a Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions, and the Natural Science Foundation of Education Committee of Jiangsu Province (12KJB150023).
A Sensitive Electrochemical Glucose Biosensor Based on Flower-Shaped Zinc Oxide Nanostructures
Authors: Li Juan , Tong Jingjing 
Published: February 2020

In this work, flower-shaped zinc oxide nanostructures were used to develop sensitive electrochemical glucose biosensor. The flower-shaped zinc oxide nanostructures were prepared by solvothermal method, which was different from the previous method [1], and characterized by scanning electron microscope and X-ray diffraction spectroscopy. A novel glucose biosensor was fabricated based on the immobilization of glucose oxidase (GOx) on the flower-shaped zinc oxide nanostructure. Flower-shaped zinc oxide with large specific surface area can load large amounts of glucose GOx, and provide excellent microenvironment for the immobilized enzyme[2,3,4,5]. Fig. 1 shows the amperometric response of the GOx/Nafion/GCE and GOx/ZnO/Nafion/GCE in pH 7.0 air-saturated PBS containing different concentrations of glucose at –0.37 V applied potential. The proposed biosensor shows a wide linear range from 0.005–1.6 mM, high sensitivity of 15.6 mA M−1 cm−2, and low detection limit of 0.004 mM. The performance of the GOx/ZnO/Nafion/GCE is much better than that of GOx/Nafion/GCE. The resulting biosensor with excellent selectivity, stability and reproducibility can be successfully applied in the detection of glucose at –0.37 V in human serum samples.
References:
[1] H. Zhang, D. Yang, Y.J. Ji, X.Y. Ma, J. Xu, D.L. Que, J. Phys. Chem. B 2004, 108, 13
[2] M. K. Ram, M. Adami, S. Paddeu and C. Nicolini, Nanotechnology, 2000, 11, 112.
[3] F. F. Zhang, X. L. Wang, S.Y. Ai, Z. D. Sun, Q. Wan, Z. Q. Zhu, Y. Z. Xian, L. T. Jin and K. Yamamoto, Anal. Chim. Acta, 2004, 519, 155.
[4] S. P. Singh, S. K. Arya, P. Pandey, B. D. Malhotra, S. K. Sreenivas and V. Gupta, Appl. Phys. Lett., 2007, 91, 63901.
[5] X. L. Zhu, I. Yuri, X. Gan, I. Suzuki and G. Li, Biosens. Bioelectron., 2007, 22, 1600.

Figure 1
Capacity Enhancement of Electrochemical Flow Capacitor Using Quinonic Compounds Couple
Authors: Saito Hayate , Tomai Takaaki , Honma Itaru 
Published: February 2020

The semi-solid flow cell system, consisting of an electrochemical charge-discharge cell connected to an external circulatory system of pumps and reservoirs, has been proposed as the grid-scale energy storage. Among the flow cells, electrochemical flow capacitor (EFC) stores electrical charge in an electrical double layer at the carbon-electrolyte interface in a flowable carbon-electrolyte suspension (slurry), so the EFC exhibits higher power density than that of semi-solid flow battery [V. Presser, et al., Adv. Energy Mater, 2, 895 (2012).]. However, compared to the battery system, EFC has the limited energy density only derived from electrical double layer capacitance.
Our previous study revealed that the impregnation of redox-active organic compounds into the nanoporous carbon enable to enhance the high energy density (＞20 Wh kg-1) of aqueous electrochemical capacitor with maintaining the high power density (＞5 A g-1) and long cycle lifetime (more than 10000 cycles) [T. Tomai, S. Mitani, D. Komatsu, Y. Kawaguchi, I. Honma., Sci. Rep.,
4, 3591, (2014).]. In this study, to address the limitation of the energy density of EFC, we employed the nanoporous carbon beads holding quinonic/hydroquinonic compounds to carbon-electrolyte suspension (quinone/carbon complex slurry) for both flowable electrodes of the EFC.
The flowable quinonic/hydroquinonic slurry electrode was prepared by dispersing the organic compound-carbon composite in 0.5 M H2SO4 and 0.05 M HCl aqueous solution. We employed tetrachlorohydroquinone (TCHQ) as cathode active material and dichloroanthraquinone (DCAQ) as anode active material in positive and negative slurry electrodes, respectively. The weight ratio of the quinonic/hydroquinonic compound to the nanoporous carbon bead was fixed to be 3:7. The weight ratio of the organic compound-carbon composite to 0.5 M H2SO4 and 0.05 M HCl aqueous solution was fixed to be 13:87. Charge-discharge measurement at static operation, the EFC using the quinone/carbon complex slurry shows the high energy density (19.4 Wh/kg) in the applied potential range between 0-1 V. This value is about two times larger than that of the EFC using the unmodified carbon slurry. Thus, by using the redox reactions of quinonic/hydroquinonic compounds in positive and negative slurry electrodes, we achieved the enhancement of the energy density of EFC. Notably, the EFC using TCHQ/carbon complex slurry and DCHQ/carbon complex slurry for both electrodes investigated in this study exhibits 1.6 times higher energy density than the EFC using only hydroquinone/carbon complex slurry [M. Boota, K. B. Hatzel, E. C. Kumbur, Y. Gogotsi., ChemSusChem 2015, 8, 835.]. Moreover, charge-discharge measurement at intermittent flow operation, we demonstrated the prepared slurry electrodes were applicable to semi-solid flow system.
Effect of Disulfite on the Solubility of Molybdate and Passivation of Iron in Concentrated LiBr Solution
Authors: Tezuka Hanami , Tsukazawa Shogo , Yashiro Hitoshi , Hirata Yoichi , Hishinuma Takashi 
Published: February 2020

[Introduction]
Absorption refrigerator utilizes highly corrosive concentrated LiBr solution as an absorbent for water vaper. In order to inhibit corrosion of carbon steel, LiOH and key inhibitor of Li2MoO4 are added into the absorbent. LiNO3 is also used as a strong passivator in order to accelerate passivation of steel especially at a startup stage. Because of the limited solubility of Li2MoO4 in the absorbent, its concentration diminishes during long-term operation not only by consumption by the reaction with steel but also by precipitation at lower temperature part of refrigerator, i.e. in an absorber. In this research, concentration change of molybdate in the absorbent is studied at the absorber temperature (40ºC) and additives that inhibit the precipitation of Li2MoO4 are searched. The effect of precipitation inhibitor on the passivation of iron are also evaluated through electrochemical measurements.
[Experimental]
The composition of the test solution is 17.3 mol kg-1 LiBr + 0.1 mol kg-1 LiOH with initial concentration of Li2MoO4 of 3.0×10-3 mol kg-1, where Li2MoO4 is supersaturated at 40ºC. The change in concentration of Li2MoO4 over time is measured at 40ºC. Several oxoacid salts are tested as a precipitation inhibitor for Li2MoO4. Electrochemical measurements are carried out for iron in the deaerated test solution at 155ºC in order to examine the effect of precipitation inhibitor (sodium disulfite) on the passivation of iron.
[Results and discussion]
The concentration of molybdate in the test solution (initially 3.0×10-3 mol kg-1) reduced gradually at 40ºC and became almost constant around 5.0×10-4 mol kg-1. The addition of sodium carbonate, sodium nitrate, sodium borate, sodium phosphate was not effective at all, while sodium sulfate delayed the concentration decrease of molybdate. Sodium disulfite and sodium sulfite (1.0×10-2 mol kg-1) showed noticeable effect: sodium disulfite, in particular, kept the molybdate concentration above 2 × 10-3 mol kg-1 at 40ºC for long time. The effect of disulfite was kept even after the test solution experienced heating up to 155 ºC with additional passivator of lithium nitrate. The time variation of corrosion potential of iron in the test solution (17.3 mol kg-1 LiBr + 0.1 mol kg-1 LiOH+ 3.0×10-3 mol kg-1 Li2MoO4) at 155 ºC indicated that passivation of iron was delayed somehow by the addition of 1.0×10-2 mol kg-1 disulfite: it took about 10 h to reach passive region, while 5 h was needed in the absence of disulfite. But the delay was made up for by the further addition of nitrate passivator: the corrosion potential shifted into passive region soon after temperature reached 155 ºC irrespectively of the presence of disulfite. Polarization curves for iron also indicated harmlessness of disulfite against passivation behavior of iron. The results suggested usefulness of disufite salt as a precipitation inhibitor for Li2MoO4 with no harm in passivation of steel.
Electrochemical Lithium Recovery from Aqueous Sources
Authors: Chung Wook-Jin , Lawagon Chosel Pepito , Nisola Grace Masbate , Gebreegziabher Hana , Albarico Jed , Lee Seong Poong 
Published: February 2020

Lithium shortage is inevitable, given the massive growth in its demand for use in transportation industry and various technologies. Consequently, recovery of lithium from seawater and brine is gaining attention to potentially alleviate the impending crisis. Two widely investigated methods for lithium recovery from seawater and brine deposits are adsorption using inorganic lithium ion sieves (LIS) and electrochemical processes. But the former has a drawback due to the use of toxic solvents which negatively affects the environment. Herein, an efficient type of lithium recovery approach is proposed by systematically designing an electrochemical system to sequester Li+ from aqueous sources.
An electrochemical cell was designed to selectively intercalate Li+ into the anode during charging phase. A microcell reactor was prepared and investigated for its feasibility to capture lithium ions (Li+). The reactor consists of a three-electrode assembly with an Li+-selective intercalating electrode, a chloride-capturing silver electrode, and Ag/AgCl reference electrode. Repetitive cyclic voltammetry and galvanostatic cycling showed highly selective and stable electrode system for aqueous Li+ uptake and release. The energy efficiency of the process was also investigated and compared with other electrochemical Li+ recovery methods. Overall, the results demonstrate the ability of the electrochemical system to selectively recover Li+ from aqueous sources. This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (2009-0093816) and Ministry of Science, ICT and future Planning (2015R1A2A1A15055407).
Facile Synthesis of Cobalt-Copper Layered Double Hydroxide Nanosheets As Cathode Catalysts for Rechargeable Lithium-Air Batteries
Authors: Shi Haohong , Liu Ying , Lu Zhouguang 
Published: February 2020

Designing novel cost-effective catalyst is one of the greatest challenges in the development of high performance rechargeable Li-air battery. Here, we present a new type of bifunctional catalyst, the cobalt-copper layered double hydroxide (LDH) nanosheets. These Co-Cu LDH nanosheets are fabricated via a simple co-precipitation method under Ar gas. The Li-air batteries with Co-Cu LDH nanosheets exhibit superior electrochemical performance comparing with that using CoCu2O4 electrode. In simulated air environment, the Li-air batteries with Co-Cu LDH nanosheets exhibit higher discharge capacity of 4870 mAh g-1 at 200 mA g-1, lower charge overpotential and better cycling stability with controlling capacity of 1000 mAh g-1. The superior catalytic activity and enhanced electrochemical performance are associated with the unique layered structure of Co-Cu LDH nanosheets and the accumulation of active Co2+ and Co3+ ions in the layers, which provide more catalytic sites for the formation/decomposition of discharge products Li2O2, avoid severe aggregation during cycling and facilitate the O2
transportation among three-phase boundary.
Acknowledgments
This work was financially supported by the Shenzhen Peacock Plan (KQCX20140522150815065), the Natural Science Foundation of Shenzhen (JCYJ20150331101823677) and the Science and Technology Innovation Foundation for the Undergraduates of SUSTC (2015x19 and 2015x12).
Carbon Nanotube Composite Electrodes Toward All Solid Alkali Metal Ion Batteries
Authors: Sakamoto Yuki , Canghao Li , Ishii Yosuke , Kawasaki Shinji 
Published: February 2020

Owing to the superior energy density, rechargeable Li-ion batteries (LIBs) have been used as a major power source of portable electric devices such as cell phones and lap-top computers. In addition to small-scale applications, LIBs are also installed in recently developed large scale systems such as electric vehicles (EVs), renewable energy storage systems, and smart grids. In commercially available LIBs, rare metal oxides, such as LiCoO2 and LiMnO4 are used for the cathode material. However, the capacity of LIB is not large enough for EV with long driving range. Furthermore, rare metals used in the present LIB such as Co, Ni and Li raise the cost of LIB. Therefore, we have to explore new electrode materials having high ion adsorption capacity and available at low cost so as to develop long driving range EV. Phosphorus is a candidate for such an electrode materials, because phosphorus is one of the ubiquitous elements and can adsorb much alkali metal ions. However, most of the polymorphs of phosphorus except for black phosphorus, which is prepared by high pressure and high temperature treatment, are electric insulators. We also take large volume change of phosphorus electrode with ion adsorption into account. Single-walled carbon nanotube (SWCNT) has good electric conductivity and huge hollow core space in which some molecules can be encapsulated. Therefore, if we input phosphorus molecules into the hollow core of SWCNT, the materials would work as a good electrode. In fact, it was found by our preliminary experiments that phosphorus encapsulated in SWCNT (P@SWCNT) can adsorb and desorb alkali metal ions such as Li and Na [1]. However, since the experiments were performed under limited conditions, we should perform more sophisticated experiments to examine the electrode properties of P@SWCNT more precisely. In this study, we discuss how the electrode property of P@SWCNT changes with different kinds of electrolytes. In the previous work, we used mixture of Ethylene Carbonate and Diethyl Carbonate (EC/DEC) as an electrolyte. In the present study, we prepared two different kinds of electrolytes: Propylene Carbonate (PC) and polyethyleneoxide based composite polymer electrolyte (PEO). The former has wide liquid temperature range and shows very good low temperature performance than EC/DEC solvent and high conductivity thus we can try to evaluate electrode material at low temperature. The latter is known for one of the solid electrolyte and show from 10-3 to 10-4 S/cm at over 60 degrees Celsius. In the symposium, we’ll discuss the electrode properties of P@SWCNT with different kinds of electrolyte and also talk about the possibility of all solid state battery using P@SWCNT.
References
[1] Y. Ishii, Y. Sakamoto, H. Song, K. Tashiro, Y. Nishiwaki, A. Al-zubaidi, S. Kawasaki, Alkali metal ion storage properties of sulphur and phosphorous molecules encapsulated in nanometer size carbon cylindrical pores, AIP Adv. 6, 035112 (2016).
Development of New Electrolytes for Electropolishing of Niobium
Authors: Kawamura Shoma , Yashiro Hitoshi , Ida Yoshiaki , Nii Keisuke , Monjushiro Hideaki , Kure-Chu Song-Zhu 
Published: February 2020

1. Introduction

In an international linear collider (ILC) plan, superconducting radio frequency (SRF) cavities are essential components for acceleration of the charged particles beam. The cavities are made of high purity niobium (Nb) and the inner surfaces of these cavities are required to be smooth enough because they play a crucial role in the performance of cavities. Typically, in order to obtain a good surface finish, electropolishing is used for the SRF cavities made of Nb. Typical electropolishing process uses the electrolyte composed of hydrofluoric acid (HF, about 55 mass%) and sulfuric acid (H2SO4, about 98 mass%) in a volumetric ratio of 1:91). However, there is a strong demand to replace the electrolyte with less hazardous one. In this study, we made a preliminary search for less hazardous electrolyte that could change the traditional HF-H2SO4 electropolishing system.

2. Experimental

Following three types of electrolytes are tried for electropolishing of Nb: 3.7 M H2SO4, 10 M NaOH and 80 mass% CH3SO3H + 3 mass% NH4HF. A square of Nb (99% +, 20×20×0.5 mm3, Nilaco) is fixed on a Teflon holder (with exposed area of 1.13 cm2) and used as a working electrode. Before electropolishing, Nb samples is polished up to #6/0 SiC paper. A plate of aluminum is used as a counter electrode except in a NaOH solution where a nickel plate is used as a counter electrode. Electropolishing is carried out under constant voltage (5 – 10 V) for 30 min at temperatures of 30 - 80ºC. In each solution, I–V character and mass change are evaluated. The Nb surface after the electropolishing is characterized by a surface roughness meter and FE-SEM.

3. Experimental results and discussion

In a 3.7 M H2SO4 solution at 30ºC, a blue oxide film was formed on Nb surface after applying 5 and 10 V. The results indicated that no polishing of Nb would proceed in this solution in a direct current mode. In a 10 M NaOH with constant voltages of 5 and 10 V, a gray-white oxide film was formed on Nb surface but no polishing proceeded either below 50ºC. At 80 ºC in a 10 M NaOH, a remarkable mass loss was observed at 10 V but the resultant surface was not very uniform. In a 80 mass% CH3SO3H + 3 mass% NH4HF at 30ºC, a gray-white oxide film formed on Nb surface at a constant voltage of 1 V. As the voltage is increased to 5 V, polishing proceeded most efficiently with mass loss of 4.3 mg cm-2 in 30 min. Further increase in voltage resulted in reduction in mass loss. The roughness of Nb surface was apparently improved in this solution.

References

1) P. V. Tyagi, M. Nishiwaki, T. Noguchi, M. Sawabe, T. Saeki, H. Hayano, S. Kato, Applied Surface Sci., 285P, 778 (2013).
2) Japan patent JP2008-95192A

Acknowledgment

The authors are grateful to Tohoku Business Federation for their financial support.
Developing a Sensitive in-Situ Rotating Ring Disk Electrode (RRDE) Detection Method for Understanding the Deactivation of Cu Catalysts during CO2 Electroreduction
Authors: Zhang Fen , Coleman Eric J. , Co Anne C. 
Published: February 2020

In response to the greenhouse effect and global energy crisis, reducing greenhouse gas emissions as well as developing alternative clean energy becomes one of the most important challenges our society is facing today. CO2 is one of the main components of greenhouse gas emitted into the atmosphere. The conversion of CO2 to more valuable products through an electrochemical pathway has the potential to efficiently utilize CO2. Among different types of metal catalysts, Cu has been considered as the best for the electrochemical reduction of CO2 to more complex hydrocarbons such as CH4, C2H4, C2H5OH and HCOO-. Although Cu-based catalysts demonstrate good catalytic activity towards the electrochemical reduction of CO2, the catalysts deactivate within hours and sometimes minutes, resulting in a drop in hydrocarbon production and a significant increase in H2evolved.
To date, the deactivation mechanism of the catalysts is not very well understood. Our goal is to develop a fast and sensitive method for detecting the intermediates and products generated from CO2 in-situ using a Rotating Ring Disk Electrode (RRDE), such that intermediate and product distribution due to the catalyst deactivation can be captured within a reasonable time frame.
The RRDE in this work uses a polycrystalline Cu disk electrode with a polycrystalline Pt ring electrode as the two working electrodes, a Pt mesh counter electrode and a reversible hydrogen electrode serves as the reference electrode. Under rotating conditions, the Pt ring electrode can be used to detect the in-situ formation of intermediate/product during the CO2 reduction reaction on the Cu disk. This work will discuss the changes in product selectivity and the deactivation behavior of Cu-based catalysts using RRDE.