bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gas Analysis Formed in Dual Carbon Battery Using LiPF6 in EC-Dmc
Authors: Inda Keisuke , Ishihara Tatsumi , Ida Shintaro , Kurihara Takuya 
Published: February 2020

Lithium ion rechargeable battery has been used in various field including mobile device and the power source for electric cars. Because of the limited capacity and rate property, advanced type new battery with large energy density as well as rate property are required at present. Dual carbon battery consists of graphitic carbon for both anode and cathode, and charge and discharge is performed by intercalation of Li and PF6 for both cathode and anode. This battery has an advantage of high discharge potential like 5V and superior rate property and expecting as an advance type battery. However,　this battery has disadvantage of low coulomb efficiency and this may be related with decomposition of electrolyte. In this study, gas formation during charge and discharge in dual carbon battery was investigated by using mass spectrometry.
Formation of gas from anode and cathode was analyzed by using H-type cell and for cathode and anode, graphitic carbon of KS-6 (TIMCAL) and MAG-D(Hitachi Kase) was used and stainless mesh was used for current corrector. Ar gas was used for carrier gas and part of carrier gas was introduced to vacuum line and analyzed with quadrupole mass spectrometer (MS).
From the result of MS analysis of the gases in DCB during charge and discharge, it was found that the formed gas in charge was mainly observed at potential lower than 4.5 V from anode and higher than 4.5 V from cathode in charging process. The formed gas was mainly assigned to C2H6, C2H4, and CO2 for both anode and cathode. Considering the potential, gas from anode seems to be assigned to formation of SEI layer and that from cathode was decomposition of electrolyte. Comparing with Li ion battery, gas formation amount is little larger in DCB and this mainly assigned to gas formation from cathode at higher potential. On the other hand, the amount of gas was strongly affected by conducting binder and electrolyte. Among the examined carbon binder, it was found that carbon black shows the smallest gas formation and so by using the carbon black, the amount of gas from cathode was suppressed. After second cycles, the amount of gas was greatly decreased and so this study revealed that gas formation is mainly observed at initial charge process.
The Catalytic Activity and Electrochemical Performance of Flower-like PEDOT for Enhanced Air Electrode of Li-Air Batteries
Authors: Yoon Seon Hye , Park Yong Joon 
Published: February 2020

Recently, the Li-air batteries have attracted a lot of attention as an alternative of lithium ion batteries (LIB), since they have higher capacity than LIB. An air electrode, a component of Li-air batteries, plays a key role in the electrochemical performance because the capacity and cycle life of Li-air batteries are highly dependent upon the air electrode. Generally, air electrode has been composed of porous carbon, oxide catalyst and binder. Among them, porous carbons act as sites for redox reaction and store the reaction products such as Li2O2 since they have large specific surface area. However, carbon in the air electrode activates side reaction caused by direct contact with electrolyte/Li2O2, which leads to accumulation of unwanted reaction products such as Li2CO3 and organic materials. These results lead to the increase of over-potential and limited cycle performance. In this study, PEDOT, a conductive polymer, was applied in base material for air electrode as an alternative to carbon. PEDOT has a catalytic activity and store the reaction products [1]. Moreover, introduction of PEDOT for base material of air electrode is expected to prevent the side reaction because it suppresses the direct contact between carbon and electrolyte/Li2O2. Specially, the PEDOT was prepared flower-like shape for enhance the active reaction area. Our approach may enhance the electrochemical performance of the air electrode due to reduction of side reaction and accumulated reaction products during cycling.

Reference

C. K. Lee, Y. J. Park, ACS Appl. Mater. Interfaces, 2016, 8 (13), pp 8561–8567
Relationship Between Discharge Profile and Pore Structure for Lithium-Air Secondary Battery
Authors: Matsuhashi Nozomi , Takeguchi Tatsuya , Kojima Miyuki , Ui Koichi 
Published: February 2020

Introduction High-capacity next-generation secondary batteries have been desired to spread plug-in hybrid vehicles and electric vehicles. Lithium-air secondary batteries have attracted much attention as the large storage secondary batteries due to their high theoretical capacity (5200 Wh kg-1). However, the reversible capacity is limited because the discharge products block the oxygen diffusion path in air electrode. The influence of the pore structure of carbon materials on the deterioration of electrochemical performance is not clear, although the carbon materials are widely studied as air electrode for lithium-air secondary batteries. In this study, we have prepared the carbon electrodes using carbon materials (CNovel MH (MH) and ketjen black (KB)) with different pore volume, analyzed the discharge products and change of pore structure by discharging.

Experimental The carbon materials (MH and KB) were mixed with PVdF (carbon : PVdF = 93 : 7 wt. %). After coating on the carbon paper as a current collector (the loading of carbon material 1 mg, electrode area 2.0 cm2), it was dried overnight at 80 oC in a vacuum to obtain carbon electrodes. The CR2032 coin type cell was assembled in an Ar-filled glovebox. It consisted of the prepared carbon electrode as a cathode, lithium foil as an anode, 1 mol dm-3 LiCF3SO3/TEGDME as an electrolyte, and Whatman glass filter GF/A as a separator. The carbon electrodes were analyzed by using FE-SEM, EDX, XRD, and the nitrogen adsorption method. For the electrochemical measurements, the discharge-charge tests were carried out (current value: 100 mA, voltage range: 2.0-4.5 V, measured temperature: 25 oC, and atmosphere: dry air).

Results and Discussion From the discharge-charge tests, the MH electrode showed higher discharge capacity than the KB electrode. Fig. 1 shows SEM images of MH and KB electrodes before and after 6 h discharge. The MH electrode has much larger volume of micropore than the KB electrode, as shown in the pore size distribution. The spherical Li2O2 particles is deposited on the surface of the KB electrode after 6 h discharge, while they are not observed on the MH electrode. The micropore structures prevent growth of Li2O2 particles for MH. The mesopore structure of the MH electrode does not change by 6 h discharge, while mesopore volume of the KB electrode clearly decreases by 6 h discharge. From these results, it was found that the deposited spherical Li2O2 particles changed not only micropore structure but also mesopore structure of carbon electrode to affect the discharge profile.

References

1) Y. Gao et al., Int. J. Hydrog. Energy, 37, 12725 (2012).
2) T. Cetinkaya et al., J. Power Sources, 267, 140 (2014).

Acknowledgments

This research was partially supported by ALCA-SPRING, JST.

Figure 1
Applications of a Novel Multi-Parametric/Multimodal Spectroscopy Apparatus on Characterization of Functional Interfaces
Authors: Zhou Lang , Arugula Mary A , Simonian Alex 
Published: February 2020

Multiparametric/Multimodal spectroscopy (MPMS), the integration of surface plasmon resonance, fluorescence, and electrochemistry based approaches provides new insights and complementary information about functional interfaces. In detection of biologically important analytes, MPMS is a promising tool, capable to provide a valuable cross-validated data in many important applications, and particularly in disease diagnosis. We have developed an integrated MPMS instrument and optical fiber spectral probe for simultaneous collection of all three parameters to quantify the components and kinetic parameters in the assembly of various functional interfaces, including covalent binding, layer-by-layer assembly, aptamer-based Electrochemical Proximity Assay (ECPA) and antibody-based ECPA. The instruments’ 3D printed flowcell integrated with multimode optic fiber, excitation laser sources (660nm), and sensing electrodes capable to record the SPR spectra, fluorescence and electrochemical data on the same platform. We have designed ECPA model system and obtained SPR signal that gives a comprehensive information about all steps of assembly, fluorescence signal corresponds specifically to the fluorophore labeled moieties, while electrochemistry will allow highly sensitive quantitative characterization of target analyte. This work not only provides quantitation information for protein targets, but allows a fundamental understanding of the kinetics in the formation of ECPA with an unprecedented level, which can overcome several key limitations of current, widely-used surface characterization technologies.
(Invited) Biomaterials Research Support at the National Science Foundation
Authors: Simonian Aleksandr 
Published: February 2020

The NSF/DMR/BMAT perspective on biomaterials research and education will be presented, as well as a description of ongoing and forthcoming research funding opportunities. It will start by providing an overview of divisions and programs at the NSF where an applicant may consider submitting proposals for biomaterials related research. Additionally, an information about several priority areas where progress in basic research is vital to addressing key national challenges will be provided. This presentation will be particularly useful to early career researchers in the field of biomaterials and biosensors.
The Biomaterials program supports fundamental materials researchrelated to (1) biological materials, (2) biomimetic, bioinspired, and bio-enabled materials, (3) synthetic materials intended for applications in contact with biological systems, and (4) the processes through which nature produces biological materials. Projects are typically interdisciplinary and may encompass scales from the nanoscopic to the bulk. They may involve characterization, design, preparation, and modification; studies of structure-property relationships and interfacial behavior; and combinations of experiment, theory, and/or simulation. The emphasis is on novel materials design and development and discovery of new phenomena.

General information on all the programs in DMR can be found on the DMR Web page: http://www.nsf.gov/div/index.jsp?div=DMR. In addition, attendees will have the opportunity to interact “one on one" with NSF BMAT Program Director.
Bismuth-Activated Graphene Nanocomposite Modified Electrode for Electrochemical Determination of Trace Heavy Metals
Authors: Lee Sohee , Piao Yuanzhe 
Published: February 2020

Heavy metals, such as Pb2+, Cd2+, and Zn2+, cause major public-health concerns due to their high stability and bio-accumulation. These heavy metals affect several human organs even at very low concentrations. Accordingly, developing simple, robust and highly sensitive analytical methods for assessing environmental pollutants in soil, water, and air samples to improve the quality of environment and human life is very important.
Graphene is an excellent nanomaterial for electrochemistry owing to its good electrical conductivity, low cost, excellent mechanical properties, and high specific surface area. To date, much research has been focused on their development for attractive applications in electroanalytical chemistry as a unique electrode material for manifolds. Moreover, chemical modification of graphene could further improve its electrochemical performance. The resultant activated graphene has a unique structure that makes it attractive as a potential material for the electrochemical determination of trace metal ions.
In this work, we developed a facile method for the preparation of a new and enhanced sensing platform based on bismuth and activated graphene. The activated graphene was prepared through chemical activation of graphene oxide with KOH to create nanopores. The surface morphology of the bismuth-activated graphene nanocomposite film modified electrode was investigated by using scanning electron microscopy and transmission electron microscopy. The electrochemical properties of the nanocomposite electrode were evaluated to examine the effects of experimental variables, such as deposition potential, deposition time, bismuth concentration, and stirring speed during pre-concentration, on the determination of trace metal ions. The bismuth-activated graphene nanocomposite electrode was applied for the simultaneous determination of trace zinc, cadmium, and lead by differential pulse anodic stripping voltammetry. The composite film integrates the unique properties of activated graphene and the advantages of bismuth electrodes, leading to enhanced sensitivity towards trace metal ions, especially zinc. The appearance of a zinc stripping peak reveals its superior sensitivity as compared to previous bismuth electrodes. The bismuth-activated graphene nanocomposite was also used as an electrode material for the sensitive determination of metal ions in a real sample. The limits of detection achieved are much lower than the guideline for drinking water quality provided by the World Health Organization. Thus, the proposed method facilitates the monitoring of trace heavy metals and can be expanded to detect other environmental pollutants.
4-(Trimethylsiloxy)-3-Pentene-2-One As a Novel Film-Forming Agent for High-Voltage LiNi0.5Mn1.5O4 Positive Electrode
Authors: Lee Tae Jin , Lee Jeong Beom , Jung Jiwon , Soon Jiyong , Ryu Ji Heon , Oh Seung M. 
Published: February 2020

As an effort to improve energy density of lithium-ion batteries (LIBs), the nickel-doped manganese spinel (LiNi0.5Mn1.5O4, LNMO) has been projected as a high-voltage positive electrode. The high working voltage (> 4.6 V vs. Li/Li+) and outstanding structural stability are advantageous with respect to energy density and cycle life. This advantage is, however, offset by the oxidative instability of electrolytes (> 4.3 V), which is even more serious at elevated temperatures.1 The commonly used electrolytes decompose and surface films deposit on the positive electrodes to lead to capacity fading.2, 3

In order to prevent electrolyte oxidation and film growth, the LNMO electrode should be passivated. To this end, the film-forming agents are added into electrolytes, which electrochemically decompose prior to the carbonate-based electrolytes to form passivation layer on the positive electrode.
In this study, 4-(trimethylsiloxy)-3-pentene-2-one (TMSPO) was tested as a film-forming agent for LNMO electrode. TMSPO is oxidatively decomposed at 3.6 V (vs. Li/Li+) prior to the oxidation reaction of the carbonate-based electrolyte (1.3 M LiPF6 in EC : EMC : DEC = 3 : 2 : 5 (v/v/v)). The surface film derived from TMSPO shows good passivation ability to improve both Coulombic efficiency and cycle life of Li/LNMO cell (Fig. 1b). Electrolyte depletion and film growth are not serious in TMSPO-added cell. In contrast, the film derived from the carbonate-based electrolyte is poorly passivating. Cell polarization resulting from electrolyte decomposition/film deposition continues to cause capacity fading.

References

1 .J. B. Goodenough and Y. Kim, J. Power Sources,
196, 6688-6694 (2011).
2. T. Yoon, S. Park, J. Mun, J. H. Ryu, W. Choi, Y.-S. Kang, J.-H. Park, and S. M. Oh, J. Power Sources,
215, 312-316 (2012).
3. D. Aurbach, B. Markovsky, Y. Talyossef, G. Salitra, H.-J. Kim, and S. Choi, J. Power Sources,
162, 780-789 (2006).

Figure 1. (a); Differential capacity plot in the 1stcharging at 25℃, and (b) Coulombic efficiency and cycle performance at 60℃

Figure 1
In-Situ XAFS Measurement of K:MnO
x
Oxygen Evolution Catalyst
Authors: Yamamoto Futaba , Yoshida Masaaki , Kondoh Hiroshi 
Published: February 2020

[Introduction]
Water splitting using solar energy is a promising approach to produce renewable hydrogen gas toward a sustainable society. For the realization of efficient photovoltaic and photoelectrochemical systems for water splitting, oxygen evolution reaction (OER) electrocatalysts have been used to catalyze water oxidation. Thus, the development of highly active OER catalysts has attracted considerable attention. Recently, manganese oxide electrodeposited in a potassium phosphate electrolyte (K:MnO
x
) was reported to function as an efficient OER electrocatalyst over a wide pH range.[1,2] Therefore, in this study, the K:MnO
x
catalyst was investigated by in-situ Mn K-edge XAFS measurements under potential control conditions.
[Experimental]
Electrochemical measurements were performed in a three-electrode Teflon cell equipped with a Pt counter electrode and an Ag/AgCl (saturated KCl) reference electrode. The K:MnO
x
catalyst was electrodeposited on a　gold-coated film in a 50 mM methanesulfonic acid electrolyte containing 0.5 mM MnCl2. In-situ XAFS spectra of the prepared samples were measured at various potentials in a 0.1 M potassium phosphate buffer electrolyte at BL 9A of the Photon factory and BL01B1 of SPring-8 as fluorescence excitation spectra.
[Result and discussion]
Figure 1 shows the Mn K-edge XAFS spectra for the K:MnO
x
catalyst at various electrode potentials between 0.2 and 1.0 V. At the potential of 0.2 V, the position of half edge energy for K:MnO
x
was observed at ca. 6549.3 eV, similar to those of the Mn3O4 and Mn2O3 references, which indicates that the electronic structure of Mn species in the K:MnO
x
is most likely the same as that of Mn3+. As the potential was changed from 0.2 to 1.0 V, the position of half edge energy gradually shifted to the higher energy around 0.6 V and then remained constant at 6552.3 eV up to 1.0 V, which shows that the Mn species in K:MnOx catalyst was oxidized from Mn3+ to Mn4+ by positive electrode potential. Figure 2 shows Fourier transformed extended X-ray absorption fine structure (EXAFS) spectra of the K:MnO
x
catalyst. The Mn-O and Mn-Mn peaks of the spectrum at 0.2 V were observed at the same positions with those of δ-MnO2, exhibiting that the structure of K:MnO
x
is similar to that of δ-MnO2. Moreover, those peaks increased when the electrode potential was changed to 1.0 V, which probably implies that the Jahn−Teller distortion with nonequivalent Mn−O and Mn−Mn distances was relaxed. Considering that the OER proceeds at higher electrode potential, the δ-MnO2 structure with lower distortion is likely to function as an active species for water oxidation catalysis.
In this presentation, we will discuss more detailed assignment for the XAFS spectra and relationship with the OER activity.

[1] Huynh, M.; Bediako, D. K.; Nocera, D., J. Am. Chem. Soc.,
2014, 136, 6002.
[2] Huynh, M.; Shi, C.; Billinge, S. J. L.; Nocera, D. G., J. Am. Chem. Soc. 2015, 2015, 137, 14887.

Figure 1
Synthesis of High Surface Area Magneli-Phase Ti5O9 from SiO2 Supported TiO2 Nanosheets
Authors: Toda Yosuke , Makino Sho , Ayato Yusuke , Mochizuki Dai , Tominaka Satoshi , Sugimoto Wataru 
Published: February 2020

Magnéli phases are substoichiometric titanium oxides with oxygen-deficiency (Ti
n
O2n-1
n = 4~10), and shows good electronic conductivity and stability in acidic solution. Synthesis of Ti
n
O2n-1 is typically conducted by reduction of TiO2 with H2 at high temperature, thus making it difficult to prepare in nanoscale and high surface area reduction. In this study, TiO2 nanosheets were deposited on SiO2 particles in order to prevent sintering and aggregation during the reduction process at high temperature.
TiO2 nanosheet colloid was prepared by exfoliation of layered H2Ti4O9∙nH2O.2 The preparation process of the nano-sized Ti
n
O2n-1 is schematically shown in Fig. 1. TiO2 nanosheet lamellar structures were fabricated on spherical SiO2 by layer-by-layer (LbL) deposition using poly(diallyldimethylammonium chloride) (PDDA) as the polycation. Alternately-layered structures (TiO2ns/PDDA)10 were obtained on spherical SiO2 by repeating the process 10 times. (TiO2ns/PDDA)10 was treated under hydrogen flow at 950˚C for 7 hours.
After hydrogen treatment, the color of the (TiO2ns/PDDA)10 changed from white to black, indicating reduction. XPS measurement revealed that the average Ti valence was 3.6+, suggesting that the n = 5 phase Ti5O9 was synthesized. TEM images of (TiO2ns/PDDA)10 and Ti5O9 on SiO2 particles are shown in Fig. 2. (TiO2ns/PDDA)10 lamellar structures are observed on the surface of SiO2 particles (Fig. 2a). After reduction, Ti5O9 with particle size of ca. 30 nm was observed on spherical SiO2 (Fig. 2b). The particle size of the obtained Ti5O9 on SiO2 was smaller than other process such as UV-irradiation1 and H2 reduction3. Thus, sintering of Ti5O9 particles was effectively suppressed during the reduction process by using SiO2 particles.
Cyclic voltammogram of Ti5O9 on spherical SiO2 in 1.0 M H2SO4 is shown in Fig. 3. Assuming a double layer capacitance of 10 ~ 20 mF cm-
2 for Ti5O9, the surface area is estimated as 50~100 m2 g-1 which is in good agreement with the particle size. The good conductivity, high oxidation resistance, and high surface area of nano-size Ti5O9 may allow its use as a fuel cell catalyst support.
1) T. Ioroi, H. Kageyama, T. Akita, K. Yasuda, Phys. Chem. Chem. Phys., 12, 7529 (2010).
2) W. Sugimoto, O. Terabayashi, Y. Murakami, Y. Takasu, J. Mater. Chem., 12, 3814 (2002).
3) T. Ioroi, Z. Siroma, N. Fujiwara, S. Yamazaki, K. Yasuda, Electrochem. Commun., 7, 183 (2005).

Figure 1
Acid Stable Bismuth Vanadate for Photo Electrochemical Chlorine Production
Authors: Rassoolkhani Alan , Cheng Wei , Nguyen Kevin , Young Graham , Tentinger Scott , McKee Austin , Hemingway Monica , Mubeen Syed 
Published: February 2020

Despite significant attention, water oxidation remains one of the largest bottlenecks for solar water splitting. This reaction produces a gas of minimal economic value while introducing kinetic losses to the system. While most research focuses on improving the kinetics minimal efforts have been undertaken to conduct other oxidation chemistries. Here we report the use of bismuth vanadate (BiVO4) for photoelectrochemical production of chlorine gas, an oxidation product possessing superior kinetics and higher economic value than the oxygen that results from standard solar water splitting. In order to prevent photo corrosion while operating in the acidic electrolyte (pH 1) an amorphous tungsten oxide protective layer was electrochemically deposited on the nanoporous BiVO4. These devices were able to demonstrate three hours of stable photocurrent while producing chlorine and hydrogen gas. Light absorbers that are stable in acidic solutions have widespread applications as the same solution is ideal for earth abundant materials that carry out the hydrogen evolution reaction taking place at the counter electrode.