bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thermally Chargeable All-Solid-State Flexible Supercapacitor for Waste Heat Harvesting and Storage
Authors: Kundu Arpan , Fisher Timothy 
Published: February 2020

Low-grade thermal energy is an abundantly available, sustainable and clean energy source. Its source includes waste heat from power plants, ocean thermal energy, geo-thermal energy, distributed solar energy among others. Conventional solid-state thermoelectric devices are limited in application due to their high cost, intrinsically low Seebeck coefficient (10-100 μV/K) and inflexible nature. Thermogalvanic systems, also known as thermocells have recently been found to be a promising alternative. These devices using the temperature dependence of electrochemical potential of redox electrolytes such as aqueous ferri/ferrocyanide possess the advantages of simple design, direct thermal-to-electric energy conversion, continuous operation, low mainte­nance, zero carbon emissions and low cost. However, these devices need to be connected to energy storage devices (battery or capacitor) by a power management circuit in order to store energy. This leads to complexity in system design and operation. Here, we demonstrate an integrated thermal energy harvesting supercapacitor device that can convert a temperature gradient applied over a short period of time, into stored charge. The stored electrical energy can be used to power an external load long after the temperature gradient is disengaged. Furthermore, it is flexible, thin, lightweight and all-solid-state which makes it ideal for powering portable and wearable devices. Electrodes consisting of graphene petals (GP) grown on conductive carbon cloth by microwave plasma chemical vapor deposition (MPCVD) are sandwiched onto a polyvinyl alcohol (PVA)/potassium ferrocyanide/ferricyanide gel electrolyte film to build a supercapacitor device. The device exhibits a Seebeck coefficient of -1.21 mV/K, a high areal capacitance near 9 F cm-2 at a current density of 0.1 mA cm-2 and excellent charge retention capability.
Fullerene Nanostructures As High-Performance Supercapacitors and Beyond
Authors: Zheng Shushu , Lu Xing 
Published: February 2020

During the past two decades, the self-assembly of organic crystals have been a hot topic widely studied by material chemists.[1] Among the potential candidate molecules, the spherical fullerene molecules are particularly attracting for their definite structures, high electronic affinity and three-dimensional (3D) electron transporting property.[2-4] In this presentation, we first systematically investigate the self-assembly behavior of various C60 polyhedron microstructures and also their extraordinarily enhanced luminescence properties. Moreover, C60 well-aligned arrays are readily prepared by a simple dip-coating process, which present excellent UV-photoresponse performances. Furthermore, a solution-processible co-assembly strategy taking advantage of charge-transfer interaction is developed to prepare needle-like fullerene (C70)/cobalt porphyrin supramolecular architectures, which possess excellent electrical conductivity and high thermal resistance. More interestingly, three-dimensional porous carbon structures with abundant functionalities are readily obtained by KOH activation of fullerene (C70) microtubes, exhibiting excellent supercapacitor performances which are much better than that of the original microtubes.[5]

References

[1] O. Ostroverkhova,
Chem. Rev. 2016, 116, 13279.
[2] D. M. Guldi, Chem. Soc. Rev.
2002, 31, 22.
[3] S. Babu, H. Möhwald, T. Nakanishi, Chem. Soc. Rev. 2010, 39, 4021.
[4] C. Park, J. Park, H. Choi, Acc. Chem. Res. 2014, 47, 2353.
[5] S. Zheng, H. Ju, X. Lu, Adv. Energy Mater. 2015, 1500871.
The Modification of the Pore Characteristics of Activated Carbon, for Use in Electrical Double Layer Capacitors, through Plasma Processing
Authors: Muriel Marcelis L. , Narayanan Rajaram , Bandaru Prabhakar R 
Published: February 2020

An important issue related to energy harness concerns obtaining high capacitance and related energy density in electrochemical capacitors (ECs), which have been mostly noted for high power density. In this paper, we address the possibility of obtaining enhanced capacitance in activated carbon based electrodes in ECs through the plasma processing, which has been hypothesized to introduce additional charge states in the electrode.
It was determined, based on extensive electrochemical experimentation and correlation of all the standard testing procedures (including constant current charge/discharge, cyclic voltammetry, and electrochemical impedance spectroscopy) that there is an optimal plasma processing at which both an increased capacitance as well as reduced resistance were observed, promising an enhancement in both energy and power density. For instance, while an increase of up to 35% of the gravimetric capacitance, along with ~ 20% decrease in resistance, was obtained through optimal plasma processing, increased plasma exposure yielded a drastic reduction (/increase) in the capacitance (/resistance).
It was also found that the capacitance and resistance modulation was a sensitive function of sample processing as well as electrochemical testing procedure. Considering the complexity of modeling realistic porous matrices, a metric to parameterize the reach of an electrolyte into the matrix has been posited.
Considering the difficulty of representing actual porous matrices, and as an alternative to relatively simplified lumped parameter models, we propose, for the first time in this paper, a new parameter indicating the reach of the electrolyte into the porous electrode, and which considers the extent to which a given testing procedure may be considered complete. We expect that our method of analysis and experimental demonstrations will have a major impact, through providing insight into understanding how the energy and power capacity of electrochemical capacitors may be enhanced.
Carbon Nanotube-Based Non-Noble Metal Catalyst for Oxidation Reduction Reaction
Authors: Nakashima Naotoshi , Yang Jun 
Published: February 2020

Development of non-platinum electrocatalyst for fuel cells and batteries with high performance, durablity, and scalability is a strong social demand for next-generation eco-friendly energy society. We here report a pristine multi-wall carbon nanotube/iron phthalocyanine (MWNT/FePc) hybrid catalyst with a well-defined nanostructure for oxygen reduction reaction (ORR) in alkaline media that meets this demand. By carefully tuning the thickness of the FePc stack layer deposited on the highly crystallized graphitic surface of the MWNT support, an ultra-high ORR activity and excellent durability were obtained. Moreover, a power density of 185 mW cm-2 at 0.8 V was obtained for a zinc-air battery using the MWNT/FePc cathode[1].

Reference

[1] J. Yang, F. Toshimitsu, T. Fujigaya, N. Nakashima, J. Mater. Chem. A, in press.
(Invited) Excited-State Dynamical Studies of Positively and Negatively Charged Excitons in Polymer-Wrapped Single-Walled Carbon Nanotube Superstructures
Authors: Bai Yusong , Olivier Jean-Hubert , Bullard George , Therien Michael J. 
Published: February 2020

Conjugated, highly charged aryleneethynylene polymers exfoliate, individualize, and disperse single-walled carbon nanotubes (SWNTs) via a single-chain helical wrapping mechanism. These semiconducting polymer-SWNT superstructures are robust in a wide range of aqueous and organic solvents, maintaining a fixed polymer helical pitch length on the SWNT surface; importantly, this single chain polymer wrapping of the SWNT surface solubilizes the nanotube at a minimal polymer:SWNT molar ratio, and provides a facile means to organize functional organic moieties at predefined intervals along the SWNT surface. We have investigated the transient absorptive and dynamical properties of positively and negatively charged excitons (i.e., hole- and electron-trions) in these semiconducting polymer-wrapped SWNT superstructures. This work exploits redox titration experiments that fix SWNT electron or hole polaron concentrations, and ultrafast pump-probe transient spectroscopic measurements that determine trion transient absorptive signatures and dynamics as functions of absolute electron- or hole-doping levels. Global analysis of these data over the entire vis-NIR spectral domain, where these systems display characteristic transient absorptive spectral signatures, provide fundamental new understanding of trion formation and decay mechanisms in semiconducting SWNTs essential for developing electro-optic and photonic materials.

Figure. (A) Structural schematic of a chiral aryleneethynylene polymer-wrapped SWNT. (B) Molecular structure of the binaphthalene-based conjugated, polyanionic semiconducting polymer,
S-PBN(b)-Ph5
. (C) Schematic illustration highlighting semiconducting SWNT hole polaron, exciton, positively charged exciton (hole-trion) states.

Figure 1
(Invited) Optical Signatures of Carbon Nanotube Excitons Coupled to Plasmonic Nanocavities and Metallo-Dielectric Antennas
Authors: Strauf Stefan 
Published: February 2020

Single-walled carbon nanotubes (SWCNTs) have recently gained tremendous interest as a nanomaterial for next generation optoelectronics and quantum photonic devices, in particular through the demonstration of quantum light emission at room temperature in doped SWCNTs [1]. For further advances and to enable practical applications in quantum information processing light enhancement strategies are required. To this end plasmonic nanocavities such as bowtie antennas feature nanometer gaps that can support ultra-small mode volumes which are particularly attractive to enhance the exciton emission of single-walled carbon nanotubes (SWCNTs). In this talk we will discuss several technique to achieve the required spectral, spatial, and orientational resonance between SWCNT excitons and nanoplasmonic modes. Both time integrated and time-resolved measurements reveal characteristic signatures demonstrating pronounced coupling in the Purcell regime. As a test system we employ co-polymer wrapped carbon nanotubes for which we have recently shown that the polymer backbone can lead to efficient acoustic-phonon localization implying long exciton coherence times and ultra-narrow linewidth [2]. In addition, we will discuss SWCNT excitons coupled to metallo-dielectric antennas and evaluate the light collection efficiency enhancements achievable with this approach. Finally, we will discuss the prospects of achieving transform limited single photons in these systems.
[1] X. Ma, N.F. Hartmann, J.K.S. Baldwin, S.K. Doorn, and H. Htoon, “Room-temperature single-photon generation from solitary dopants of carbon nanotubes”, Nature Nanotech 10, 671–675 (2015).
[2] I. Sarpkaya, Ehsaneh D. Ahmadi, Gabriella D. Shepard, Kevin S. Mistry, Jeffrey L. Blackburn, and S. Strauf, “Strong Acoustic Phonon Localization in Copolymer-Wrapped Carbon Nanotubes”, ACS Nano 9, 6383 (2015).
Miniaturized Ascorbic Acid Fuel Cells with an Ion-Exchange Films and Flexible Electrodes Made of Graphene-Coated Carbon Fiber Cloth
Authors: Doi Toshinari , Hoshi Kazuki , Muramatu Kazuo , Sumi Hisato , Nishioka Yasushiro , Imai Satomitsu 
Published: February 2020

Ascorbic acid (AA), also known as vitamin C, is an environmentally biologically friendly compound and a stable and non-toxic powder. AA exists in many products such as sports drinks, fruit, and in human blood. Thus, AA is expected to be an alternative fuel for potable power supplies. Fujiwara et al. reported an ascorbic acid fuel cell (AAFC) without catalysts on the anode [1]. However, these AAFCs were not portable. Recently, Hoshi et al. reported a miniaturized AAFC with an area of 0.3 cm2 using a flexible graphene-coated carbon fiber cloth (GCFC) [2]. The AAFC exhibited lower power density of 34.1µW/cm2 in a buffer solution containing 100 mM AA at room temperature and the lifetime is not reported. Further improvement in their power density is needed for their application as portable AAFC and the lifetime should be investigated.
In this study, we optimized a miniaturized and flexible AAFC using a GCFC. The power density of the optimized AAFC in a mcllvaine buffer solution (MBS, pH 5.0) containing 100 mM AA at room temperature was 155.7 µW/cm2 at 0.375 V (Fig. 1a). Although this value is approximately five times greater than that of previous studies Hoshi et al. reported, the lifetime is substantially short. Since AA oxidizes on GCFC electrodes, ion-exchange films is needed for inhibiting crossover. We also fabricated a miniaturized and flexible AAFC incorporating ion-exchange films. The power density of the AAFC incorporating ion-exchange films in a MBS containing 100 mM AA at room temperature was 32.7 µW/cm2 at 0.221 V and the performance lasted about 50 % for 12 hours (Fig. 1b).
References
[1] N. Fujiwara, K. Yasuda, T. Ioroi, Z. Siroma, Y. Miyazaki, and T. Kobayashi: Electrochem. Solid-State Lett. 6, A257 (2003).
[2] K. Hoshi, K. Muramatsu, H. Sumi, and Y. Nishioka: Jpn. J. Appl. Phys. 55(4S), (2016).

Figure 1
Planar-Type Na-Metal Halide Battery: Low Operating Temperature, Low Cost and Long Cycle-Life
Authors: Chang Hee Jung , Lu Xiaochuan , Jung Keeyoung , Sprenkle Vincent , Li Guosheng 
Published: February 2020

Energy storage systems (ESS) have gained great attentions recently for grid-scale applications. Among various types of batteries, Na-beta alumina batteries (NBBs), which are based on a β"-Al2O3 solid electrolyte (BASE) and a molten sodium anode, have been considered as a promising technology due to their high energy density, high efficiency, and good cycle life. Two types of NBBs, sodium sulfur (Na-S) and sodium-metal halide (Na-MH) batteries, have been investigated and commercialized in the past. Despite of being considered as a relatively new and less popular technology compared to Na-S batteries, Na-MH battery can provide several advantages over a Na-S battery including lower operating temperature (280oC for Na-MH vs. 350oC for Na-S), safe cell-failure mode, higher output voltage and safe assembly in the discharged state without preloading metallic sodium in the anode.
Our Na-MH battery researches in PNNL are primarily focused on developing advanced planar-type Na-MH batteries operated at temperatures below 200oC. It was found that lowering operating temperature helps to retain the long-term stability and higher energy density by slowing down materials degradation. Lowering operating temperature also provides opportunities to deploy conventional high temperature polymers as sealing materials, which can greatly reduce cell manufacturing costs. In this presentation, we will present the important correlation between cathode formula and battery performances, and will discuss about the design and testing results of larger planar cells aiming practical applications.
Liquefied Gas Electrolytes for Electrochemical Energy Storage Devices
Authors: Yang Yangyuchen , Rustomji Cyrus Sam , Meng Ying Shirley 
Published: February 2020

Electrochemical energy storage devices, such as Li-ion batteries and electrochemical capacitors, have seen little change in their electrolyte chemistry since their commercialization. These liquid electrolytes often limit the energy density and low-temperature operation of these devices, which hinder many potential applications. Our work uses electrolytes based on solvent systems which are typically gaseous under standard conditions and show excellent performance in electrochemical energy storage devices. It is demonstrated that these novel solvents have excellent performance over an extended temperature range and a wide potential window of stability. Fluoromethane based electrolytes demonstrate a high coulombic efficiency for cycling dendrite-free lithium metal anodes. Lithium batteries show excellent low-temperature operation down to -60 °C with high capacity retention. Electrochemical capacitors, using difluoromethane based electrolytes, show outstanding performance and a wide operation temperature range from -78 to +65 °C with an increased operation voltage.
Flow Batteries Containing Solid Dispersions of Lithium-Ion Active Material Redox Couples
Authors: Gupta Devanshi , Qi Zhaoxiang , Koenig Gary 
Published: February 2020

Large scale flow battery energy storage has long been considered as a potential candidate for smart grid batteries because of their design flexibility, safety and high current densities. However, one limitation of flow batteries for certain applications is their relatively low power density, which is fundamentally due to limited solubility of active species in the electrolyte which leads to the formation of precipitates at high concentration and/or high temperature. To overcome energy density limitations several methods/improvements have been reported in the battery research literature, including: polymer based flow batteries, new active materials, ionic liquids, and hybrid flow batteries with multiple redox couples.
Semi-solid flow batteries, first reported using lithium-ion chemistry by Duduta et. al1 use high energy density lithium storage compounds within a suspension/slurry in a redox flow battery. This system also relies on a nanoscale conducting network of carbon particles to provide electronic contact between the active material particles and increase active material participation in the flow channel. Their reported energy density was an order of magnitude greater than conventional flow batteries; however, the carbon network resulted in a highly viscous electrolyte requiring high pumping energy. This poster will describe carbon-free redox flow couples with solid electroactive materials in electrolyte suspensions. LiCoO2 (LCO) and Li4Ti5O12 (LTO) were used as the active cathode and anode active materials, respectively.2 The use of solid active materials and lithium-ion battery materials and electrolytes expands both the voltage range and volumetric energy density of the electrolyte. Without carbon the dispersions with sub-micron LTO and LCO particles have reduced viscosity compared to semi-solid flow batteries due to the absence of carbon conducting additives. The lack of carbon results in dramatic decreases in power density due to lower active material participation. The impacts of active material loading on electrochemical and rheological behavior in multiple cell designs will be described.
1. Duduta, M., Ho, B., Wood, V. C., Limthongkul, P., Brunini, V. E., Carter, W. C., & Chiang, Y. M. (2011). Semi‐Solid lithium rechargeable flow battery. Advanced Energy Materials, 1(4), 511-516.
2. Qi, Z., Liu, A. L., & Koenig, G. M. (2017). Carbon-free Solid Dispersion LiCoO2 Redox Couple Characterization and Electrochemical Evaluation for All Solid Dispersion Redox Flow Batteries. Electrochimica Acta.
(Olin Palladium Award of the Electrochemical Society Address) Corrosion Mechanisms at the Atomic or Nanometric Scale
Authors: Marcus Philippe 
Published: February 2020

In this Award Lecture I will emphasize a surface science approach that allows to reach a deep understanding of the mechanisms of corrosion at the atomic or nanometric scale. I will show the link between atomic/nanometric scale mechanisms and the macroscopic corrosion manifestations. The lecture will include the combined experimental approaches using advanced surface analytical and electrochemical methods with theoretical approaches based on atomistic modeling.
The high resolution techniques used in combination with classical electrochemical methods will be presented, high resolution meaning high space resolution, as achieved by near field microscopies (Scanning Tunneling Microscopy and Atomic Force Microscopy), high energy resolution in electron spectroscopy for chemical analysis, and high mass resolution for surface molecular analysis by Time-of-Flight Secondary Ions Mass Spectrometry.
The formation of the metal-water interface occurring when a metal surface is exposed to water, which has been investigated by in situ Scanning Tunneling Microscopy, will be presented.
A major part of this address will be devoted to passivity of metals and alloys, a central issue in corrosion science and engineering since the formation of ultra-thin surface oxide films is the best of all means for protection of metallic materials against corrosion. I will discuss the growth mechanisms, the nanostructure, and the electronic properties of passive films, as well as passivity breakdown and initiation of localized corrosion, with emphasis on atomic and nanoscale data.
Cathodic reactions on oxidized metal surfaces will then be discussed, with a theoretical approach of the di-oxygen reduction on surface oxide films on Al surfaces using DFT.
Finally I will mention recent work on corrosion inhibition by adsorbed organic molecules, an area in which progress has been recently achieved by combining quantum chemical calculations (DFT) with experiments.
Redefining the Electrochemical Kinetics of Redox Reactions on Passive Metals
Authors: Macdonald Digby D. 
Published: February 2020

The kinetics of redox reactions are described by specifying a standard exchange current density and a transfer coefficient that locates the position along the reaction coordinate at which the activated complex (transition state) occurs. However, this formulation was originally developed to describe charge transfer reactions on bare metal surfaces. In the case of a passive metal, however, the barrier layer of the passive film represents a barrier to the quantum mechanical tunneling of charge carriers (electrons and electron holes) between the metal and the redox reaction center and theory shows that this barrier has a profound effect upon the tunneling probability and hence upon the values of the exchange current density and the Tafel constant. In this presentation, the role of quantum-mechanical tunneling of charge carriers through the barrier oxide layer on a passive metal, in determining the electrochemical kinetic parameters is explored theoretically. The exchange current density for a redox reaction occurring on the passive metal surface is assumed to be the product of the exchange current density on the bare metal surface and the quantum mechanical tunneling probability (QMTP) of charge carriers through the barrier layer, which is inversely proportional to the exponential of the barrier thickness and the tunneling constant that in turn is proportional to the square root of the product of barrier height and the effective electron mass. The QMTP is used to redefine the exchange current density for the cathodic reaction (e.g., reduction of oxygen), as measured on the passive surface, to that on the (hypothetical) bare metal alone. Thus, knowing the voltage, the barrier layer thickness can be calculated from the Point Defect Model (PDM), which in turn can be used to estimate the QMTP for that particular set of conditions. Then, the exchange current density for the redox reaction on the passive metal surface is calculated and used, if the barrier height and the effective electron mass are constants, in the generalized Butler-Volmer equation to describe the current/voltage characteristics of the redox reaction. In doing so, it becomes evident that the kinetics of a redox reaction are fully determined by specifying a (hypothetical) exchange current density and transfer coefficient of the reaction on the bare metal (“hypothetical” because the bare metal condition may not be realizable experimentally), the QMTP, the electric field strength within the barrier layer, the polarizability of the barrier layer/solution interface, and the potential of zero thickness of the barrier layer. The application of this theory is illustrated with respect to the hydrogen electrode reaction (HER) on passive carbon steel and on aluminum and in predicting the corrosion potentials of stainless steels and nickel alloys in the primary coolant circuits of water-cooled nuclear reactors.