bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thin Layer Sonoelectrochemistry in Aqueous and Non-Aqueous Systems
Authors: Rathuwadu Nadeesha , Dey Patrick , Leddy Johna 
Published: February 2020

In thin layer sonoelectrochemistry, ultrasonic sound waves introduced into an electrolyte layer increases the rates of heterogeneous processes [1, 2]. From previous studies of thin layer sonoelectrochemistry, the rates of heterogeneous electron transfer, oxygen reduction reaction (ORR), and methanol electrolysis were facilitated under sonication. In the thin layer of electrolyte, ultrasound energy is reected into the electrolyte at the electrolytejair meniscus to minimize the losses from attenuation found in bulk systems. This harvests the ultrasonic energy more e¢ ciently. The observed e/ects are on interfacial rates and not mass transport. No cavitation is thus far observed. These e/ects have been observed at platinum electrodes in aqueous electrolytes when the interfacial reactions are slow. The studies were done at a single frequency and varied intensity.
The fundamental mechanism of thin layer sonoelectrochemistry is not yet fully understood. Here, studies are undertaken to broaden inspection of experimental parameters. This identies critical parameters of the ultrasonic input (e.g., frequency, intensity, duty cycle) and the electrochemical system (e.g., solvent properties of viscosity and density, electrode materials). The data informs the models.
In this study, thin layer sonoelectrochemistry was undertaken on academically interesting reactions in aqueous and non aqueous electrolytes. Redox probes include tris(bipyridine)ruthenium(II) chloride (Ru(bpy)2+
3 ), iron ( III ) (Fe3+) and p-benzoquinone (p-BQ). These choices allow comparison of fast (Ru(bpy)2+
3 ) and slower (Fe3+) heterogeneous electron transfer rates as well as coupled proton electron (p-BQ) processes in different solvents. Cyclic voltammetry measurements were performed on a Pt wire working electrode against a shrouded Pt/PtO2 quasireference electrode (QRE). The ultrasonic transducer is placed in the cell but is electrically isolated from the electrochemical measurement circuit. The electrolytes are HNO3/H2SO4 in aqueous and tetrabutylammonium tetrauoroborate (TBABF4) in non-aqueous solvent DMF. The outcomes of these studies will support fundamental understanding of the thin layer sonoelectrochemical mechanisms.
References
[1] C.G. Duda, Thin Layer Sonoelectrochemistry, Ph.D. 2012, University of Iowa
[2] J. Leddy, C. G. Duda, J. Lyon, and W. J. Leddy III, Thin Layer Sonoelectrochemistry and Sonoelectrochemistry Devices and Methods, U.S. Patent Application 20150147594 A1.
Impact of Battery Size and Charge on the Thermal Runaway of Lithium Ion Batteries
Authors: Lamb Joshua , Steele Leigh Anna M , Orendorff Christopher J 
Published: February 2020

Catastrophic battery failure is typically studied at or near full charge of the battery. This is generally assumed to be the worst-case scenario, and it is taken as conventional wisdom that the risk of thermal runaway is very low below 50% state of charge. Further, due to cost and safety issues, the bulk of laboratory scale battery abuse testing and careful calorimetry work is performed on relatively small cells (<5 AH). However, little has been reported on how data collected using these smaller cells scales to the large cells proposed for advanced energy storage applications, such as electric drive vehicles and grid scale energy storage. This work looks at how thermal failure of lithium ion batteries may scale as both the size of the battery and state of charge are changed. Different battery chemistries are observed using over temperature (thermal ramp) testing as well as large volume Accelerating Rate Calorimeters (ARC) to observe how the energy release and kinetics of thermal runaway scale as battery size increases, and through this discuss the benefits and limitations of smaller scale calorimetry.
ARC is used as well to observe the nature of thermally induced battery failure as the state of charge changes. As part of these results we explore the difference between the total heat released during battery failure, which has been observed to scale relatively linearly with state of charge, and the kinetics of battery failure, which has been observed in this work to scale exponentially at high states of charge (>80% SOC). A large format battery at a low state of charge may still have the potential for a significant amount of energy release even if a rapid thermal runaway is unlikely. This is of particular concern in large battery systems where well insulated cells in close contact with one another may see a propagating failure due to the significant amount of energy available to heat surrounding cells even if the thermal runaway of a single cell is unlikely.
Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.
Electric Double Layer Capacitor Properties of Pillared Carbons
Authors: Matsuo Yoshiaki , Fukuda Takuya , Kimizuka Osamu , Nishijima Motoaki , Kinoshita Hajime 
Published: February 2020

Recently, carbon materials with controlled pores such as mesoporous carbons, template carbons, carbon nanotubes, etc are attracting much attention for the electrode materials of electric double layer capacitor (EDLC). In this context, we have prepared pillared carbons in which adjacent graphene layers are connected with each other by silsesquioxane pillars and they possess micro or mesopores between their graphene layers and pillars [1,2]. Though the width of the space between pillars available for the entrance of foreign molecules was less than 0.4 nm, BF4
- ions can be intercalated into the pillared carbon [3]. The capacity per surface area was larger than that of activated carbon, indicating that the surface of pillared carbon was more effectively utilized for energy storage [3]. In this study, we have prepared pillared carbons with various surface area and the EDLC properties of them were investigated. Pillared carbons were prepared from the thermal reduction of silyalted graphite oxide. By using graphite oxide with different oxygen contents and various siylating reagents, pillared carbons with the surface area between 380 and 650 m2/g were obtained. The constant current charge-discharge measurement at 80 mA/g was performed by using two-electrode symmetric cell. The upper limit voltage was changed every 5 cycles from 2.0 to 3.5 V. The capacity of the resulting pillared carbons increased as the increase in the upper limit voltage and the pillared carbons were gradually activated. The capacity almost linearly increased and reached 19.6 F/g. The X-ray diffraction measurement of the charged negative electrode indicated that larger cations were also intercalated into pillared carbons.

References

1) Y. Matsuo, et al, Chem. Lett., 36, (2007) 1050-1051.
2) Y. Matsuo, et al, Chem.Commun., 47 (2011) 4409-4411.
3) Y. Matsuo, et al, Carbon, submitted.
Simplified Lithium-Ion Capacitors with Irreversible Lithiated Materials in the Positive Electrode
Authors: Jezowski Pawel , Crosnier Olivier , Poizot Philippe , Brousse Thierry , Béguin François 
Published: February 2020

The lithium-ion capacitor (LIC) is a high energy hybrid system which combines an electrical double-layer (EDL) positive electrode made from nanoporous carbon with a negative intercalation electrode made from graphite or hard carbon [1,2]. The electrolyte is a lithium salt (LiPF6) which is generally dissolved in ethylene carbonate:dimethyl carbonate (EC:DMC) mixture. The most common concept of LIC uses an auxiliary metallic lithium electrode for graphite pre-lithiation [1,2]. Since this additional lithium electrode complicates the cell construction and might be the cause of thermal runaway during LIC operation, alternative strategies have been considered. Pre-lithiation has been proposed directly from the electrolyte [3], but it leads to a decrease of electrolyte concentration and conductivity, which might have a negative impact on the LIC power. A better strategy to lithiate the negative electrode consists in irreversible lithium de-intercalation from lithium metal oxide (Li2MoO3, Li5FeO6, Li0.65Ni1.35O2) incorporated together with activated carbon in the positive electrode [4,5]. However, for some of these oxides, the extraction potential of lithium ions exceeds 4.5 V vs. ref. Li/Li+, which causes detrimental electrochemical oxidation of the electrolyte.
The first objective of this presentation is to design new materials from which high amounts of lithium can be irreversibly de-intercalated at potential lower than 4.2 V vs. Li/Li+. For example, we demonstrated that lithium can be irreversibly extracted at 3.3 V vs. Li/Li+ with a capacity of ca. 350 mAh/g during galvanostatic oxidation of the renewable organic derivative C6H3CN(OLi)2; the LIC cell based on the use of this material demonstrates an excellent cycle life in the potential range from 2.2 ~ 4.0 V. The second objective is to investigate materials with the lowest residual mass after the delithiation step. We will show that this can be achieved by selecting materials which liberate neutral gases simultaneously to lithium deintercalation. Hence, after this step, the positive electrode contains only activated carbon, leading the system to display much higher energy density.
[1] N. Ando, S. Takasi, H. Taguchi, Y. Hato, Organic electrolyte capacitor, EP1400996A1 (2002)
[2] T. Aida, K. Yamada and M. Morita, Electrochem. Solid-State Lett. 9 (2006) A534.
[3] V. Khomenko, E. Raymundo-Piñero, F. Béguin, J. Power Sources 177 (2008) 643.
[4] M.-S. Park, Y.-G. Lim, J.-H. Kim, Y.-J. Kim, J. Cho and J.-S. Kim, Adv. Energy Mater. 1 (2011) 1002.
[5] P. Jeżowski, K. Fic, O. Crosnier, T. Brousse, F. Béguin, Electrochim. Acta (2016) http://dx.doi.org/10.1016/j.electacta.2015.12.034.
Vanadium Nitride Electrodes: Limitations and Practical Use in Electrochemical Capacitors
Authors: Brousse Thierry , Morel Alban , Bélanger Daniel , Borjon-Piron Yann 
Published: February 2020

Vanadium nitride has displayed many interesting characteristics for its use as a pseudocapacitive [1] electrode in an electrochemical capacitor, such as good electronic conductivity, good thermal stability, high density and high specific capacitance. Thin films of VN were prepared by D.C. reactive magnetron sputtering. The electrochemical stability of the films as well as the influence of dissolved oxygen in 1 M KOH electrolyte were investigated. In order to avoid material as well as electrolyte degradation, it was concluded that vanadium nitride should only be cycled between -0.4 and -1.0 V vs. Hg/HgO. After a 24 hours stabilization period, the prepared VN thin film showed an initial capacitance of 19 mF.cm-2 and a capacity retention of 96% after 10000 cycles. Furthermore, dissolved oxygen in the electrolyte was demonstrated to cause self-discharge up to a potential above -0.4 V vs. Hg/HgO, where VN was shown to be unstable. Additionally, the presence of oxygen was shown to shift the open circuit potential of a VN electrode to about 0 V through self-discharge processes [2].
Since the performances reached on thin film electrodes are difficult to translate to VN powder, the use of VN thin films in hybrid microdevices has been investigated [3]. Microdevices were designed using VN thin films as negative electrode and electrodeposited Co3O4 as positive electrode in order to combine the high capacity of the Faradaic type cobalt based electrode and the high capacitance and good cycling ability of VN electrode when used in an optimized electrochemical window. The performance of such devices will be reported and discussed with regards to existing literature on the field.
References
[1] Brousse, T.; Belanger, D.; Long, J. W. J. Electrochem. Soc. 2015, 162, A5185–A5189.
[2] Morel, A.; Borjon-Piron, Y.; Lucio Porto, R.; Brousse, T.; Bélanger, D.; J. Electrochem. Soc. 2016, 163, A1077-A1082.
[3] Eustache, E.; Frappier, R.; Porto, R. L.; Bouhtiyya, S.; Pierson, J.-F.; Brousse, T. Electrochem. Commun. 2013, 28, 104–106.
Solid-State Microsupercapacitors Assembled Using Ionic Liquids for Wide Temperature-Range Applications
Authors: Teng Hsisheng , Chang Pei Yi , Huang Hsin-Chieh 
Published: February 2020

Microsupercapacitors (MSCs) have the potential to serve as power sources or energy storage units in microelectronic devices.1 We have reported a laser micromachining technique to produce in-plane interdigitated microelectrodes for microsupercapacitors, in which the electrode fingers were fabricated using high-porosity activated mesophase pitch.2 The use of an ionogel, comprising an ionic liquid and fumed silica, enables the MSC to reach stack capacitance of 12 F cm-3, stack energy of 16 mWh cm-3, and stack power of 160 W cm-3. These energy and power values are unprecedented for MSCs. The developed laser machining technique is highly scalable, enabling lithography-free fabrication and on-chip integration of MSCs into microelectronic units. We obtained results demonstrating that the laser-patterned interdigitated design substantially reduces the resistance for electrode-electrolyte interfacial diffusion and drift transport through the carbon films. The challenge of solid-state MSCs in versatile applications is the operation temperature range and high thermal stability.
In this report, we present the use of an ether-bridged dication ionic liquid as an additive to commercially available ionic liquids to enable operation of MSCs at temperatures ranging from -20 to +60 ºC. The proposed fabrication strategy, using a laser for the micromachining in conjunction with a wide temperature range ionogel, provides an opportunity for the development of robust solid-state MSCs applicable a variety of micro/nano-sized energy devices.

References

1. M. Beidaghi, Y. Gogotsi, Energy Environ. Sci. 7 (2014) 867.
2. H.C. Huang, C.J. Chung, C.T. Hsieh, P.L. Kuo, H. Teng, Nano Energy 21 (2016), 90

Acknowledgments: This research was supported by the Ministry of Science and Technology, Taiwan (104-2221-E-006-231-MY3, 104-2221-E-006-234-MY3, 105-3113-E-006-005, and 104-3113-E-006-011-CC2), and by the Ministry of Education, Taiwan, The Aim for the Top University Project to the National Cheng Kung University.
Facile Synthesis of Nickel Cobalt Layered Double Hydroxides Microspheres with High Pseudocapacitive Performance
Authors: Zha Daosong , Han Qiaofeng , Wang Xin 
Published: February 2020

To meet the ever-growing demand for peak-power assistance in portable electronics and electric vehicles,considerable efforts have been devoted to the development of pseudocapacitorelectrode materials with superiorspecific capacitance and excellent rate performance. Transition metal hydroxides such as Ni(OH)2 possesses hightheoretical specific capacitance, butits unsatisfactory ratecapability is confinedby the inferior intrinsic conductivity [1]. Encouragingly, theintegration of more conductive Co(OH)2 can significantly improvespecific capacitanceand rate capability [2].
In the present work, a facile one-step and cost-effective solvent thermal strategy was adopted to obtain Nickel–cobalt layered double hydroxides microspheres (LDHMs) with hierarchical architecture.Methanol without any other solvent was selected as reaction menstruumduring the whole reaction process, along with urea as alkaline source.Meanwhile, neither surfactant nor template was introduced.All electrochemical tests of all as-prepared microspheres with different Ni/Co atomic ratio (NixCo1-xLDHMs) were performed using 2M KOH aqueous electrolyte. This unique architecture was assembled by numerous ultrathin nanoflakes with an average thickness of about 30 nm randomly and tightly.
Particularly, Ni0.6Co0.4LDHMs exhibitedthe most outstandingelectrochemical performance and rate performance, including an ultrahigh specific capacitance of 1624F/g at 0.5A/g,while even at a high current density of 10A/g,the specific capacitance still maintained as high as 1531F/g (~94.27% capacitance retention). Otherwise, the Ni0.6Co0.4LDHMs also exhibited an excellent long-term cycling stability. An ultrahigh retention about 89.94%of specific capacitance was acquired after 8000 cycles of continuousgalvanostaticcharge-discharge processes at 4A/g.
The remarkable elecrochemical performance may arise from both the unique morphorlogy and the synergistic effect between the binary hydroxides components [3]. All these results demonstrate that our research can provide a novel way to easily fabricate the structure tunable materials with improved capacitance behavior for energy storage/conversion devices.

References:

[1] Shang C, Dong S, Wang S, et al. [J]. ACS nano, 2013, 7(6): 5430-5436.
[2] Qu L, Zhao Y, Khan A M, et al. [J]. Nano letters, 2015, 15(3): 2037-2044
[3] Trang N T H, Van Ngoc H, Lingappan N, et al. [J]. Nanoscale, 2014, 6(4): 2434-2439
Electrochemical Characteristics of Large Area Thin Film Supercapacitors for Flexible Electronic Applications
Authors: Yoo Jung-Joon , Kim Young Il , Kim Jong-Huy 
Published: February 2020

Electronic products have been asked to be small, light, safe, eco-friendly and even flexible. Supercapacitors are one of the great candidates of the next generation rechargeable energy storage devices for the portable electronic devices.
Here, we have proposed a new fabrication approach for making a large area thin film supercapacitor that achieved moderate areal capacitance and robust mechanical and thermal strength. The total thickness of a packaged device was ~0.3 mm. The fabricated devices had the electrode dimension of 10x10 cm2. They showed good mechanical flexibility with no change in the capacitance of the device after 1000 bending cycles with the bending radius of 20 mm and superior long-term thermal stability for for 2,000 hours at 60℃. It indicated that the unique film-type energy storage device for commercial small electronic applications has been developed.
High Performance Supercapacitors Electrode Based on N-Doped Carbon Nanofibers
Authors: Liu Rong , Zhang Fangping , Li Enyuan , Xu Jun , Yuan Guohui 
Published: February 2020

Supercapacitors (also known as electrochemical capacitors) are considered to be the most promising devices to meet the urgent and pressing requirements of energy storage. Supercapacitive electrode materials, which are strongly related to the high-efficiency storage of energy, have provoked more attentions and interests. Heteroatom doping (nitrogen, oxygen, phosphorus, boron et.al) has been conceived as a promising approach to increase the special surface area, tune pore size distribution, and incorporate pseudo-capacitance. Recently, nitrogen-doped three-dimensional (3D) nanostructured carbon electrode materials have attracted immense interest due to their great potential merits, including enhance the electrical conductivity, surface polarity, wettability and electro-active surface area, provide an additional pseudo-capacitance and achieve high rate performance and good cycling stability.
Herein, a simple, eco-friendly, novel, and effective way to fabricate N-doped carbon nanofiber networks (N-CNFs) is studied. The N-CNFs are successfully fabricated through in situ polymerization using pyrrole and ammonium persulfate as the monomer and oxidant, respectively, then followed by pyrolyzed in a nitrogen atmosphere. The fabricated electrode exhibits an excellent reversible specific capacitance of 233.5 F g-1 at the current density of 0.5 A g-1, and a high rate performance of 80.2 % retention at 5 A g−1 in 6.0 mol L-1 KOH electrolyte. The exceptional properties mostly stem from robust redox reactions of N-doping in the CNFs, which providing enhanced pseudo-capacitance. Furthermore, this kind of hybrid doped material could be easily scaled up and represents an alternative promising candidate for an efficient electrode material for supercapacitors.
Thermal Energy Harvesting Using Carbon Nanotube and Polymer Aqueous Electrolyte Composite
Authors: Kazim Ali Hussain , Cola Baratunde 
Published: February 2020

Thermo-electrochemical cells (thermocells) convert temperature difference to electricity with no moving parts and is an inexpensive technology to harvest waste heat. However, low power conversion efficiency and power output has limited its use from being a commercial application. In a thermocell, when a temperature difference is applied at the electrodes, oxidation and reduction takes place at the hot and cold electrodes respectively. The electron released at the hot electrode (anode) due to oxidation of ion passes through the external circuit, while the oxidized ion moves towards the cold electrode (cathode) where it is reduced and the cycle repeats. To minimize the over potentials at the electrode/electrolyte interface (interfacial charge transfer resistance) due to electronic transport, concentration polarization near the electrode interface (mass transfer resistance) due to ions, transport of ions in the bulk fluid (ohmic resistance) are the primary requirements for high energy conversion efficiency.1 Increasing the flux of charge carriers to flux of heat flowing between the electrodes is also needed. In this work, the effect of mixing carbon nanotubes (CNT) and poly (3,4-ethylenedioxythiophene)−poly(styrenesulfonate) (PEDOT:PSS) composite in aqueous potassium ferri/ferrocyanide electrolyte is characterized using electrochemical impedance spectroscopy. Here we report a 10% decrease in ohmic resistance and 5-fold decrease in interfacial charge transfer resistance. The decrease is ohmic resistance is attributed to increase in PEDOT:PSS ions and interfacial polarization2 due to CNT present in the electrolyte. While the decrease in interfacial charge transfer resistance is attributed to composite increasing the contact area at the electrode/electrolyte interface.3, 4 The composite electrolyte improved the power performance of the standard electrolyte by about 30% and gave a stable output over a 30 day period suggesting that it can be used for long term operation.
1. T. Quickenden and C. Vernon, Solar Energy, 1986, 36, 63-72.
2. P. F. Salazar, S. T. Stephens, A. H. Kazim, J. M. Pringle and B. A. Cola, Journal of Materials Chemistry A, 2014, 2, 20676-20682.
3. T. Kato, T. Kado, S. Tanaka, A. Okazaki and S. Hayase, Journal of the Electrochemical Society, 2006, 153, A626-A630.
4. C. P. Lee, K. M. Lee, P. Y. Chen and K. C. Ho, Solar Energy Materials and Solar Cells, 2009, 93, 1411-1416.