bluuebunny/crossref_metadata_2025 huggingface dataset:
Surface Structure Design of Lithium-Rich Layered Cathode Materials Based on Framework and Interlayer Structures
Authors: Kim Sangryun , Cho Woosuk , Zhang Xiaobin , Oshima Yoshifumi , Choi Jang Wook
Published: February 2020

The limited specific capacity of cathode materials is one of the main issues for further enhancement of the energy density of the rechargeable lithium ion batteries. Lithium-rich layered oxides are considered one of the most promising cathode materials because their specific capacities often exceed 200 mAh g-1 due to the additional lithium occupation in the transition metal layers [1]. However, this lithium arrangement, in turn, triggers cation mixing with the transition metals, driving a phase transition of the overall crystal framework to spinel and/or rocksalt structures during cycling and thereby causing a decrease in the operation voltage and specific capacity [2]. Surface modification has been one of the primary remedies because the given phase transition is typically initiated from the surface of the particle and well-designed surface structures can suppress this transition process from the initial step. In this study, we report an artificially designed high performance surface structure (Li2MnO3) bearing a consistent lithium-rich layered framework with the host, in which nickel is regularly arranged between the transition metal layers. X-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), scanning transmission electron microscopy (STEM), and electrochemical impedance spectroscopy (EIS) characterizations reveal that the prepared surface structure effectively suppresses unwanted phase transitions, leading to substantially improved cycling and rate performance. The structure and electrochemical properties of the surface-modified lithium-rich layered oxide electrode will be discussed, along with a detailed reaction mechanism.

[1]  C. S. Johnson et al., Electrochem. Commun. 6, 1085 (2004).

[2]  K. G. Gallagher et al., Electrochem. Commun. 33, 96 (2013).
Effect of Local Strcutral Changes on Rate Capability of LiNi0.5Mn1.5O4-a Cathode Material for Lithium Ion Batteries
Authors: Yoon Jaesang , Um Ji Hyun , Kim Hyunchul , Jeong Mihee , Choi Woo Sung , Lee Hayeon , Yoon Won-Sub
Published: February 2020

Due to its high working voltage (4.7 V vs. Li/Li+ for Ni2+/Ni4+ redox couple), high theoretical capacity (147 mAh/g), and inherent cyclic stability (no Jahn-Teller distortion from Mn3+), LiNi0.5Mn1.5O4 is a promising cathode material for the practical application in high energy density lithium ion batteries [1-3]. The cation ordering, the degree of presence of Mn3+ in the spinel structure, is regarded as an important factor influencing the electrochemical properties of LiNi0.5Mn1.5O4 [4, 5].

  With a simply strategy of cooling rate, the degree of ordering in disordered spinel LiNi0.5Mn1.5O4-δ structure is controlled at 0.5 oC/min for slow cooled spinel and at 5 oC/min for fast cooled spinel. From XRD and FTIR analyses and charge/discharge profiles, it is confirmed that the fast cooled spinel develops more disordered structure than the slow cooled spinel, retaining more oxygen vacancies and more abundant Mn3+. Moreover, through in situ XRD analysis, the more disordered spinel follows the extended solid-solution reaction in favor of Li+transport, which results in an improved rate capability. But, the local structure information of interesting atoms without a destructive interference which can arise from long-range structural order is highly related to the electrochemical performance. Therefore, the examination in local structural variations of interesting atoms is essential for understanding their electrochemical properties.

  In this work, we investigate local structural changes in the vicinity of Mn and Ni cations at various C-rates by using ex situ XAS analysis and quantify the structural changes by fitting a theoretical model to the extended X-ray absorption fine structure data. This finding will propose that a change of structural distortion can be another platform to understand the enhanced Li+transport in the disordered spinel and offer valuable guidance for developing LiNi0.5Mn1.5O4, a promising cathode material with high rate capability for next generation rechargeable batteries. More detailed discussion will be presented at the 2016 IMLB meeting. 

[1]. X. Liu, D. Li et al., J. Alloys Compd.,2014, 609, 54-59. 

[2]. X.-W. Gao, Y.-F. Deng et al., J. Mater, Chem. A.,2015, 3, 404-411.

[3]. H. Xia, Y.S. Meng et al., J. Electrochem. Soc., 2007, 154, A737-A743.

[4]. M. Kunduraci and G.G Amatucci, J. Electrochem. Soc.,2006, 153, A1345-A1352

[5]. L. Wang, H. Li et al., Solid State Ionics., 2011, 193, 32-38
X-Ray Scattering Analysis of the Morphology of TiO2 (B) Nanoparticles
Authors: Hua Xiao , Liu Zheng , Bruce Peter G. , Grey Clare P.
Published: February 2020

The morphological characteristics of a nanomaterial, i.e., geometric shape and dimension, and the arrangement of atoms, which both vary depending on specific nanostructures, have a considerable impact on properties such as electronic structure, ionic diffusion, and surface structure. It is, therefore, essential to determine the nanomorphology of the electrode materials so as to link shape with the electrochemical performance. 

Conventional microscopy methods used to characterize the morphology of nanomaterials sometimes involve practical challenges arising from the aggregation of nanoscopic structure. In order to determine the morphology of a TiO2 (B) nanoparticle sample that shows excellent electrochemical performance1,2, we have performed a comprehensive X-ray scattering analysis of SAXS, PDF and XRPD data. The scattering pattern within a particular angular range encodes distinct structural features of the materials ranging from mesoscale to nanoscale. The combination of small- and wide-angle measurements therefore covers a full angular range that enables us to access a complete set of morphological and structural characteristics including size and shape via SAXS, particle asymmetry and long-range structure via XRPD, and short-range atomic ordering via PDF.

From the analyses, we conclude that the particles are oblate-shaped, contracted along the [010] direction. This particular morphology provides not only a plausible rationale for the excellent electrochemical behavior of these TiO2(B) nanoparticles, but also a structural foundation to model the strain-driven distortion induced by lithiation. A more complex displacement model incorporating this lithiation-induced strain was developed making use of the oblate particle model. It clearly shows the importance of determining the morphology of the nanoparticle so as to understand the lithiation mechanism and rationalize the rate performance of nanostructured materials.

Reference:

[1] Ren, Y.; Liu, Z.; Pourpoint, F.; Armstrong, A. R.; Grey, C. P.; Bruce, P. G. Angew. Chem. Int. Ed. 51 (2012) 2164-2167.

[2] Andreev, Y. G.; Panchmatia, P. M.; Liu, Z.; Parker, S. C.; Islam, M. S.; Bruce, P. G. J. Am. Chem. Soc. 136 (2014) 6306-6312.
In Situ Study of the Cathode Electrolyte Interphase in High Voltage Cycling with Atomic Force Microscopy
Authors: Lu Wei , Chen Liwei
Published: February 2020

Charging layered cathode materials such as LiCoO2 to a higher voltage may simultaneously enhance the specific capacity and average operating voltage, and thus improve the energy density of lithium ion battery (LIB). However, the battery cycle life is influenced by the lattice instability and undesired oxidation reactions of the electrolyte, which will degrade the structure of cathode materials, consume the limited electrolyte and hamper the charge transfer at cathode/electrode interface. In all these factors, cathode electrolyte interphase (CEI), a layer in-situ formed at the cathode-electrolyte interface in high voltage, is critically important for the performances of LIB cycling at high voltage. Investigating the formation mechanism and evolution processes of CEI layer are important for the understanding the high voltage cathode degradation process and crucial in improving high voltage cycle stability of LIBs. Here we present an in-situ atomic force microscopy (AFM) investigation of CEI on LiCoO2 at high voltage. The formation of CEI is only observed at the LiCoO2 edge plane, not at the basal plane. Thin layer of Al2O3 coating completely suppresses the formation of CEI at the edge planes, and is shown to significantly improve coin cell high voltage cycle stability. And we also used this technique to study the CEI evolution on LiNi0.5Mn1.5O4 cathode with ~5.0 V working voltage.
A One-Pot Route for Uniform Deposition of Metal Oxide and Metal Sulfide Nanoparticles on Reduced Graphene Oxide Using Supercritical Alcohols
Authors: Kim Jaehoon , Yoon Dohyeon
Published: February 2020

Supercritical fluids can offer environmentally benign and facile synthetic conditions for developing new electrode materials of lithium 2nd batteries, owing to their unique physical properties, including low viscosity, fast diffusion, zero surface tension, and tunable physical properties. These factors make supercritical fluids promising media for overcoming some of the barriers associated with other techniques, which include the generation of toxic reaction waste, difficulty in producing nanosize materials, and transport limitations in material synthesis. Recently, we proposed an environmentally benign, supercritical alcohol-based route to produce reduced graphene oxide without the use of reducing agents. Herein, the fabrication of a RGO-based anode electrode with a high rate performance and large capacity by a simple, supercritical alcohol-based route. The control of RGO properties by adjusting the exfoliation and oxidation degree of GO and production of hydrogen-enriched RGO by the reaction of oxygen functionalities on GO with supercritical alcohol can remarkably enhance the lithium storage capacity even at high insertion/deinsertion rates. Supercritical alcohols can provide one-pot deposition route of metal oxide nanoparticles on RGO and simultaneous reduction of GO to RGO. For example, numerous anchor sites facilitating heterogeneous nucleation of metal oxide particles on GO, and extremely fast nucleation due to the supercritical alcohol led ultrafine, well-dispersed metal oxide nanoparticles to anchor to the RGO sheets in a single step. The unique synthetic approach developed herein was very effective for preventing restacking of graphene sheets during reduction, and for tightly anchoring metal oxide nanoparticles to the RGO surface. Various types of metal oxide-RGO composites (SnO2-RGO, Fe3O4-RGO, MoO2-RGO) and metal sulphide-RGO (MoS2-RGO) are synthesized in supercritical alcohols. The characteristics and electrochemical performance of the composite materials are discussed.

Figure 1
System Considerations for the Application of Thermal Management Solutions to Electrified Vehicle Traction Batteries: Benchmarks and Technical Specification Development
Authors: Robert Brian
Published: February 2020

With an increasing demand in traction battery performance for electrified vehicles, thermal management definition and temperature uniformity specifications are a moving target for supplier product development and OEM system integration. Alternative cell formats, integration schemes and cell-to-pack scaling are trending stop-gaps to this challenge. Highlights of select vehicle system benchmarks and the evolving demands for lithium-ion battery thermal management will be discussed with focus on scaled temperature gradients, heat transfer efficiency, as well as system volume, weight, and cost. Recent efforts by the United States Advanced Battery Consortium to define such targets and SAE standards defining battery thermal management systems will be also be explored.
(Industrial Electrochemistry and Electrochemical Engineering Division H. H. Dow Memorial Student Achievement Award Address) Electrochemically Active Hybrid Materials for Pseudocapacitive Energy Storage
Authors: Boota Muhammad , Gogotsi Yury
Published: February 2020

Electrochemically active hybrid materials are an emerging class of materials for both small and large-scale electrochemical energy storage applications. The possibility of nanoscale engineering inorganic and organic components in a unique hybrid material provides new and sometimes exceptional sets of properties, which makes them attractive for a variety of applications.1 While organic/inorganic hybrid nanomaterials exhibit tremendous potential for the pseudocapacitive energy storage, the choice of an optimal organic material and nanostructured inorganic support impedes their energy storage applications.2

We will present the exciting development of pseudocapacitive hybrid materials for both static and flowable energy storage systems.3–7 Our approach includes a combination of suitable redox active organic molecules with various types of carbon nanostructures and/or highly conductive metal carbides (MXenes).8 These combinations improve conductivity, resulting in high energy and power density pseudocapacitive electrodes with improved cycling performance. Using experimental techniques and molecular simulations, we will discuss the interfacial organic-inorganic interactions, charge storage mechanisms, and preferred molecular orientations of organic molecules at the interface. Remaining challenges and future opportunities for improvement in nanostructured hybrid materials for the electrochemical energy storage will be highlighted.

1. H. Wang and H. Dai, Chem. Soc. Rev., 42, 3088–3113 (2013)

2. D. Vonlanthen, P. Lazarev, K. a. See, F. Wudl, and A. J. Heeger, Adv. Mater., 26, 5095–5100 (2014).

3. M. Boota et al., Adv. Mater., 28, 1517–22 (2015)

4. M. Boota, K. B. Hatzell, E. C. Kumbur, and Y. Gogotsi, ChemSusChem, 8, 835–843 (2015).

5. M. Boota, C. Chen, M. Bécuwe, L. Miao, and Y. Gogotsi, Energy Environ. Sci., 9, 2586–2594 (2016).

6. M. Boota et al., ChemSusChem, 8, 3576–3581 (2015)

7. K. B. Hatzell, M. Boota, and Y. Gogotsi, Chem. Soc. Rev., 44, 8664–8687 (2015)

8. M. Naguib, V. N. Mochalin, M. W. Barsoum, and Y. Gogotsi, Adv. Mater., 26, 992–1005 (2014)
Electrochemical Energy Storage of Ni-Doped Metal Organic Framework and Reduced Graphene Oxide Composites
Authors: Chakraborty Banerjee Parama , Lobo Derrek , Shaibani Mahdokht , Majumder Mainak
Published: February 2020

Metal Organic Frameworks (MOFs) are crystalline, open-porous materials consisting of metal ions or metal-oxo units coordinated by electron donating organic ligands and possess very high surface area, well defined pore sizes, tailorable structure and permeability to guest molecules. MOFs have been widely used in catalysis, gas separation, drug storage and delivery, imaging and sensing, optoelectronics and molecular sieving. Although these chemical building blocks can participate in electron exchange processes with the likelihood of providing rich fundamental data; utilizing these materials for energy storage application have been limited. In the present study, composites of a Ni-doped MOF with reduced graphene Oxide (rGO) are synthesized in bulk (gram scale) quantities. The composites are composed of rGO sheets which avoid restacking from the physical presence of MOF crystals. Ni in Ni-doped MOF is found to engage in a reversible, efficient, redox reaction shuttling between Ni and Ni(OH)2 in aqueous potassium hydroxide (KOH) electrolyte. Employing electrochemical impedance spectroscopy, we determined the charge transfer resistance to be 184 mΩ for MOF, 74 mΩ for a Ni doped MOF and 6 mΩ for an rGO-Ni-doped MOF composite, but these modifications do not affect the mass transfer resistance. This redox reaction in conjunction with the lowered charge transfer resistance from the introduction of rGO underpin the synergy which dramatically increases the capacitance to 758 F/g in the rGO-Ni-doped MOF composite, when the parent MOF could store only 100 F/g and a physical composite of rGO and Ni-doped MOF could algebraically achieve about 240 F/g. A generic approach of doping MOFs with a redox active metal and forming a composite with rGO transforms an electro-inactive MOF to high capacity energy storage material with energy density of 37.8 Wh/kg at a power density of 227 W/kg. These results can promote the development of high performance energy storage materials from the wide family of MOFs available.
Engineering Palladium Surfaces to Enhance the Electrochemical Storage of Hydrogen
Authors: Hamm Steven C. , Knies David L. , Dmitriyeva Olga , Cantwell Richard , McConnell Matt
Published: February 2020

Materials can be engineered to have enhanced hydrogen storage capabilities during electrolysis by modifying the composition of the first few surface layers at the electrolytic interface. The proper choice of surface layer can radically affect the electrochemical insertion of hydrogen. To this end, between 1 μg cm−2 and 23 μg cm−2 of Pb was deposited onto Pd cathodes during galvanostatic experiments in the 0.1 M LiOH electrolyte. The optimum surface doping level 2.9 μg cm−2 (~1.4 mass equivalent monolayers) of Pb was found to achieve the highest quantity of inserted hydrogen at a potential of approximately −0.5 V vs RHE. Additionally, the hydrogen content increased from PdH0.75 to PdH0.86 with increasing Pb amounts up to 2.9 μg cm−2 at a constant current of −14.5 mA cm−2. For comparison, the same change in hydrogen content from pressurized gas loading experiments would require an increase in hydrogen fugacity from about 6 to 1420 atm. Furthermore, the addition of a small amount of Pt co-deposited with the Pb resulted in a further increase in hydrogen content to PdH0.89 at −14.5 mA cm−2. Preliminary analysis suggests the Pb and Pt are changing the balance between the Volmer, Heyrovsky, and Tafel reaction rates, which changes the chemical potential of the adsorbed hydrogen, and ultimately controls the hydrogen insertion. This work provides a fundamental basis for the future design of surface alloys yielding enhanced electrochemical hydrogen insertion in Pd and other hydrogen absorbing materials.
Expanded Graphite(EG)/ Chitosan(C) Coated Separators for Highly Stable Lithium Sulfur Batteries
Authors: Abbas Syed Ali , Wang Pen-Cheng , Chu Chih-Wei
Published: February 2020

Lithium sulfur battery (LSB) has been considered as a promising candidate for next-generation energy storage systems, due to its high theoretical specific capacity (1675mAh/g). However, the poor cycling life hinders in its commercial production. The short cycling life results from continuous loss of active material in the form of lithium polysulfide’s during a typical charging and discharging process, commonly known as shuttling phenomenon. In this abstract i will discuss our unique approach of dual (physical, chemical) interaction mechanism based on EG/C coated separator to stop the lithium polysulfide shuttle. The light weight EG/C coated separator (0.13mgcm-2 ) can extend the cycling life of LSB to 3000 cycles at 1C-rate (1C= 1675mA/g) as shown in the figure below; reducing the decay rate to 0.02% per cycle which is among the best reported up to date. Live in-situ electrochemical discharging results shows that the modified separator works effectively in curbing the polysulfide shuttle. Flexible batteries based on modified separator were also fabricated and able to light up 4 parallel LED circuit.

Figure 1
Quantifying Tortuosity of Porous Li-Ion Battery Electrodes: Comparing Polarization-Interrupt and AC Impedance (Blocking-Electrolyte) Methods
Authors: Pouraghajan Fezzeh , Knight Hannah , Mazzeo Brian A , Wheeler Dean R
Published: February 2020

Tortuosity is a geometric parameter of porous electrodes that quantifies the tortuous path ions take to meet electrons in order for the chemical reaction to take place on the surface of the active material. Ionic resistance in the electrodes, which is directly related to the tortuosity, is a key factor that influences battery performance, and must be accurately represented in battery models. This work is intended to help battery researchers understand and be able to reliably determine the tortuosity of different electrodes.

The polarization–interrupt method previously developed in our research group is an effective way to directly measure electrodes tortuosity [1]. This method determines tortuosity based on effective diffusivity in the sample by solving diffusional equations along with the polarization-interrupt experiment. It requires that an electrode film be delaminated from its current collector. The blocking electrolyte method is another technique used for measuring tortuosity that was recently introduced by Gasteiger and coworkers [2]. This method is based on an AC-impedance measurement of the electrode sample using a non-intercalating or blocking electrolyte. In this method the tortuosity is determined based on an effective conductivity fit with a transmission-line model.

In this work the two methods were used to determine the tortuosity of the several Li-ion cathodes and anodes. The results from each method are compared and the advantages, disadvantages, and validity of each method are discussed. Furthermore, for the blocking electrolyte method, we investigated the effects of different salts and solvents on the obtained tortuosity and discuss the implications on choosing an electrolyte for this method. We also added extra terms to the transmission-line model to account for contact impedance in the active material film and current collector interface in both the electronic and ionic path to help the model to better capture the experimental data.

This work was supported by the U.S. Department of Energy through the BMR program.

--------------------------------------------------------------------------------------------------------

[1]
Thorat et. al., Journal of Power Sources, vol. 188, p. 592–600, 2009.

[2]
Landesfeind et. al., Journal of The Electrochemical Society, vol. 163, p. A1373-A1387, 2016.

Figure 1: Example results for the two techniques: a) cell potential during a polarization-interrupt experiment and b) Nyquist impedance plot of blocking-electrolyte experiment.

Figure 1
Developments in Benchtop Spectrometers: A High Access XANES User Facility and a Compact Spectrometer for Energy Storage Research
Authors: Jahrman Evan , Seidler Gerald T. , Ditter Alex , Holden William , Hoidn Oliver , Mortensen Devon , Valenza Ryan , Bradshaw Liam , Kozimor Stosh , Bowden Mark E , Zhang Jason , Gross Mark , Cartmell Samuel , Li Qiuyan , Murugesan Vijayakumar , Govind Niri , Wang Wei
Published: February 2020

Until recently, advanced x-ray spectroscopy was largely the sole domain of synchrotron facilities. While national-lab scale sources provide the ultimate in technical capability, the present access model is necessarily restrictive to the point of slowing progress on critical projects and prohibiting more routine analytical characterization. Over the last three years, our group at the University of Washington has been developing several new families of lab-based instruments for x-ray absorption fine structure (XAFS) and high-resolution x-ray emission spectroscopy (XES). This poster will first report on the installation of a hard x-ray XAFS user facility for battery research in the University of Washington Molecular Analysis Facility (MAF) before detailing the development of a small-scale spectrometer for benchtop XES measurements at energies down to a few keV.

The UW-MAF’s recent installment of a laboratory XANES spectrometer provides users with a valuable tool for high-throughput transition metal and lanthanide speciation studies. The instrument is available as a mail-in service for academic, industry, and national lab scientists, making it ideal for system prototypes in need of rapid feedback. The spectrometer is further recommended for such studies by its sub-eV energy resolution and high flux provided in transmission-mode. Selected applications reported here include redox flow batteries, Li-ion batteries, and a low absorption pouch cell design for in operando studies. This latter-most capability was developed in collaboration with the Pacific Northwest National Laboratory.

Another area of active research within our group is the development of XES spectrometers for lower energy applications, such as x-ray emission from sulfur and phosphorous. Our new instrument is surprisingly small, yet provides synchrotron-level performance in both energy resolution and count rates. Ongoing developments include its integration into a glove box system to facilitate the study of air-sensitive systems such as are relevant for Li-S battery research and development
Electrochemical Reaction and Direct Energy Conversion of Macroalgae Biomasses By Functional Nanomaterial Modified Electrodes
Authors: VU Huong THI
Published: February 2020

Biomass extracted from brown macro-algae promises as a future renewable energy because of non-toxicity, natural availability, and greenhouse gas free and do not interfere with the human food chain. Here, we first show the extraction of energy from brown macro-algae by via direct oxidation of macro-algae biomasses by using the novel materials combination of gold nanoparticles (AuNPs), titania (TiO2) and functionalized multi-walled carbon nanotubes (f-MWCNTs). The catalytic activity for macro-algae biomasses oxidation of composites materials was tested by both of cyclic voltammetry and chronoamperometry methods. In all experiments, TiO2/Au/CNT nanocomposites exhibited better electrochemical performance than TiO2/CNT composites; AuNPs/CNT composite or CNTs only. Enhanced current response can be attributed to the synergic effect of nano-TiO2, nano-Au and f-MWCNTs. Furthermore, the new materials showed improvement on both direct fucose and alginate fuel cell performance. The results from this research open possibility for practical application of our fuel cell by using the cheap catalytic material of TiO2 with high efficiency on conversion of energy from brown macroalgae biomass.

Figure 1
Evaluation of the Electrolyte Charge Process and the Operation Process of a Vanadium Redox Flow Battery with Potentiostatic and Galvanostatic Perturbations in Different Volume Schemes
Authors: Ribadeneira Paz Rafael , Mora Mera César Augusto
Published: February 2020

The energy storage technologies are primordial for the working of several applications at high power density and low power density. Particularly, for intermediate and big electric applications and grid administration and support, which need high power density such as auxiliary power units, the vanadium redox flow batteries are an interesting option for the energy storage because of their low cost compared with more complex systems, durability, independence between energy density and power, large discharge time and their relatively simplicity in components considering their material constituents and well behaved - chemical internal processes [1-2].

In this work, a simple laboratory prototype of a vanadium redox flow battery with spectroscopy carbon electrodes is utilized to test two classic electrochemical perturbations, a potentiostatic perturbation and a galvanostatic perturbation in the charge of electrolytes process and in the operation of the battery, also using three different volume schemes, aiming to establish the best way to transfer charge in the preliminary electrolyte charge process and in the operation of the battery.

As main results, it is found that the battery has a better electrolyte charge process and a better operation process with the potentiostatic perturbation with a volume ratio of 2:1 between the anodic compartment and cathodic compartment. Also a comparison of the state of charge of this battery and the charge/discharge curves with others in literature is achieved, showing a good behavior of the tested conditions [3-7].

1. P. Alotto, M. Guarnieri, and F. Moro, “Redox flow batteries for the storage of renewable energy: A review,” Renew. Sustain. Energy Rev., vol. 29, pp. 325–335, Jan. 2014.

2. X. Wu, H. Xu, Y. Shen, P. Xu, L. Lu, J. Fu, and H. Zhao, “Treatment of graphite felt by modified Hummers method for the positive electrode of vanadium redox flow battery,” Electrochim. Acta, vol. 138, pp. 264–269, Aug. 2014.

3. M. R. Mohamed, H. Ahmad, M. N. A. Seman, S. Razali, and M. S. Najib, “Electrical circuit model of a vanadium redox flow battery using extended Kalman filter,” J. Power Sources, vol. 239, pp. 284–293, 2013.

4. A. Z. Weber, M. M. Mench, J. P. Meyers, P. N. Ross, J. T. Gostick, and Q. Liu, “Redox flow batteries: a review,” J. Appl. Electrochem., vol. 41, no. 10, pp. 1137–1164, Oct. 2011.

5. M. Skyllas-Kazacos and F. Grossmith, “Efficient Vanadium Redox Flow Cell,” J. Electrochem. Soc., vol. 134, no. 12, p. 2950, 1987.

6. M. Skyllas-Kazacos, G. Kazacos, G. Poon, and H. Verseema, “Recent advances with UNSW vanadium-based redox flow batteries,” Int. J. Energy Res., vol. 34, no. 2, pp. 182–189, Feb. 2010.

7. G. Colt, “Evaluación de una celda redox de vanadio,” no. 1, pp. 183–188, 2010.

Figure 1
High Performance, Biodegradable Electrochemical Capacitors for Transient Electronics
Authors: Lee Geumbee , Kang Seung-Kyun , Won Sang Min , Gutruf Philipp , Jeong Yu Ra , Koo Jahyun , Lee Sang-Soo , Rogers John A , Ha Jeong Sook
Published: February 2020

Various electronic devices with high performance and advanced structures have been effectively integrated into a functional electronic system owing to their miniaturization. In particular, extensive research on miniaturized devices that gradually lose their functionality by dissolution in water/biofluid has been recently conducted, which would accelerate the development of eco-friendly as well as bio-implantable devices for transient electronics. To satisfy the technological demand for continuous powering of implanted devices in the human body regardless of the time and place, the development of high performance wireless power generation and energy storage devices is required. Supercapacitors, so-called next-generation energy storage devices, can be used in the event of unexpected power-off owing to their superior power density and long cycling lifetimes compared to batteries. Therefore, the application of transient supercapacitors as devices essential to integrated electronic circuits in the human body is expected to play an important role in the advancement of independent and sustainable transient electronics.

Here, we introduce the fabrication and applications of fully biodegradable microsupercapacitors (MSCs) consisting of interdigitated water-soluble metal (W, Fe, and Mo) electrodes, a hydrogel electrolyte (agarose gel), and a biodegradable poly(lactic-co-glycolic acid) (PLGA) substrate, encapsulated with thin films of PLGA and polyanhydride. In particular, this unusual energy storage device based on 300 nm thick Mo electrode exhibits electrochemical performance with a areal capacitance of 1.6 mF/cm2, energy density of 0.14 µWh/cm2, and power density of 1.0 mW/cm2. Such high performance is attributed to the pseudocapacitance originating from the metal-oxide film generated by electrochemical corrosion at the interface between the metal electrode and the water-containing agarose gel electrolyte, during repeated charge/discharge cycles. The oxidation states of those oxide layers are confirmed to be WO3, Fe2O3, and MoO3, respectively, via taking scanning electron microscope images and x-ray photoelectron spectra. The dissolution kinetics of all components of the MSCs are measured in phosphate-buffered saline at body temperature and an encapsulation strategy is suggested to control the functional lifetimes of the MSCs. Finally, we demonstrate the potential applications of the fabricated biodegradable MSCs as transient energy storage devices by illuminating a light-emitting diode and as a transient capacitor in integrated circuits for wireless power transmission.
Synthesis of Self Nitrogen/Phosphorus Doped Carbon Derived from Pea Protein As an Efficient Electrode Material for Supercapacitors
Authors: Demir Muslum , Gupta Ram B.
Published: February 2020

Supercapacitors are energy storage devices that have many applications from memory storage devices, vehicle power supplies, micro sensors and so on. Recently, the electrode material of supercapacitors have been manufactured from fossil fuels which have many concern for depletion therefore, there is urgent to find low cost, eco-friendly and advance carbon electrode materials. In this context, the development of nitrogen-doped porous activated carbons from biomass is of significance for electrode materials. Herein, we report a simple route to prepare phosphorons/nitrogen-doped porous carbon derived from pea protein via hydrothermal carbonization (HTC) and the post-annealing treatment. The surface, textural and morphological properties of synthesized materials were investigated by SEM, XPS, Raman, FTIR and surface area analyzer. A series of mesoporous carbon up to 7.6 N and 2.2 wt. % P along with high the BET surface were synthesized successfully. The obtained materials depicts graphitic carbon particles. Electrochemical properties of the prepared materials were analyzed by cyclic voltammetry (CV), charge-discharge (CD), electrochemical impedance spectroscopy (EIS), KOH and H2SO4 electrolyte solution. The PGC-700 shows outstanding capacitive performance (299 F g-1 at 1 A g-1) , good rate capacitive , and excellent cycling stability due to the synergistic effect of N, P-doped species. This work opens up a new way to prepare advance N/P-doped carbon materials with tailored properties.
(Invited) Dielectric Response and Quantum Motion of Lithium Cations Trapped inside Carbon Cages
Authors: Aoyagi Shinobu
Published: February 2020

Endohedral fullerenes trapping atoms and molecules with magnetic and electric moments have a potential to be used for quantum computing. A C60 fullerene trapping a Li+ cation has an electric monopole moment, and forms a rock-salt-type cubic crystal, [Li@C60](PF6). The dielectric response and quantum motion of the Li+ cations in the crystal at low temperature were revealed by the dielectric and X-ray diffraction measurements [1]. The Li+ cations are moving inside the C60 cages by the hopping and tunneling motion between the potential wells under 20 hexagons above 100 K. The Li+ motion is suppressed to be localized at two equivalent positions on the threefold inversion axis with decreasing temperature below 100 K. The simultaneous occupation of the Li+ cation at the two positions is mainly achieved by the tunneling motion. The hopping motion is slowing down and hindered by the energy barriers between the wells. The tunneling motion is also hindered below T
C = 24 K by the antiferroelectric interactions among local electric dipole moments formed between the Li+ cations inside and the PF6
− anions outside the C60 cages. The tunneling motion and intermolecular interaction of the Li+ cation found in [Li@C60](PF6) show that Li+@C60 has a potential to be used as a qubit in a quantum computer using electric dipole moments.

[1] S. Aoyagi, A. Tokumitu, K. Sugimoto, H. Okada, N. Hoshino, and T. Akutagawa, J. Phys. Soc. Jpn.
85, 094605 (2016)
(Invited) Single Crystal Structures, Unique Bonds, Redox Properties and Photoluminescence Activity of Actinide Endohedral Fullerenes
Authors: Chen Ning , Wang Yaofeng , Zhang Xingxing , Echegoyen Luis , Feng Lai
Published: February 2020

Endohedral metallic fullerenes have been intensively studied in recent years. However, the knowledge of these fullerenes largely came from the investigation of fullerenes encapsulated with lanthanide metals, which present similar physicochemical properties in most of cases. Actinide endohedral fullerenes, though have been known since the beginning of endohedral fullerenes studies, have been unexplored with the respect to their detailed structures and properties. Herein, our study on Th@C82 and U2C@I
h-C80, for the first time, demonstrated remarkably different electronic and spectroscopic properties of actinide endohedral fullerenes compared to those of lanthanide EMFs. Crystallographic study unambiguously discloses the fine structure of Th@C
3v(8)-C82. Combined experimental and theoretical studies suggest that Th@C
3v(8)-C82 has a surprisingly large electrochemical bandgap of 1.51 eV, which agrees with four-electrons-transfer from the metal to the cage. Moreover, Th@C
3v(8)-C82 displays a strong vibrationally coupled photoluminescence signal in the visible region, which is unprecedented for both fullerene and thorium compounds. The crystallographic and computational studies of U2C@I
h-C80 reveal a unique axial U=C bond, by far the shortest U-C bond and has never been experimentally proved before.

Figure 1
(Invited) Stabilization of Giant Fullerenes C2(41)-C90 , D3(85)-C9
2 , C1(132)-C94 , C2(157)-C96 , C1(175)-C98 , D5(450)-C100 , Cs(574)-C102
and C2(816)-C104
by Encapsulation of a Large La2C2 Cluster
Authors: Zhao Shasha , Cai Wenting , Lu Xing
Published: February 2020

Endohedral metallofullerenes (EMFs) with a composition of M2C2n may exist as di-EMFs, M2@C2n, or as carbide cluster metallofullerenes (CCMFs), M2C2@C2n-2. Thus care needs to be taken to distinguish between these two possibilities. However, there are rare examples for M2C2@C90-104 and the configuration of the carbide cluster is not clear in these cages.

Herein we report the isolation and single-crystal X-ray crystallographic characterization of eight unprecedented EMFs containing a La2C2 cluster, namely, La2C2@C2(41)-C9
0, La2C2@D3(85)-C92, La2C2@C1(132)-C9
4, La2C2@C2(157)-C96, La2C2@C1(175)-C98, La2C2@D5(450)-C100,  La2C2@Cs(574)-C102, and La2C2@C2(816)-C104. It is evident that the cage length increases roughly along with increasing of the carbon atom number, resulting in an increase of the La-La distance and the Ni···cage distance as well. This is a clear indication that giant fullerenes tend to grow along the long axis to achieve a tubular appearance. Encapsulation of a large La2C2 cluster inside D5(450)-C100 induces a 5% axial compression of the cage, as compared with the structure of La2@D5(450)-C100. Moreover, it is demonstrated that the defective cage of C2(816)-C104 is a starting point to form the other three tubular cages known so far, i.e., D5(450)-C100, Cs(574)-C102, and D3d(822)-C104, presenting evidence for the top-down formation mechanism of fullerenes. Overall, our experimental results have unambiguously confirmed that La2C92-10
6
 tend to form CCMFs La2C2@C90-
104 instead of di-EMFs La2@C92-10
6
.

R
eferences：

[1] Lu, X.*; Akasaka, T.*; Nagase, S. Acc. Chem. Res. 2013, 46, 1627-1635.

[2] Cai, W.; Bao, L.; Zhao, S.; Xie, Y-P.; Akasaka, T.; Lu X. J. Am. Chem. Soc. 2015, 137, 10292-10296.

[3] Cai, W.; Li, F-F.; Bao, L.; Xie, Y-P.; Lu X*. J. Am. Chem. Soc. 2016, 138, 6670-6675.
(Invited) Epoxide-Type Oxygen-Doped Carbon Nanotubes and Their Applications for NIR Imaging Probes
Authors: Okazaki Toshiya
Published: February 2020

A novel procedure for effective synthesis of covalently oxygen-doped single-walled carbon nanotubes (SWCNTs) has been developed. The SWCNT thin film is directly irradiated by UV light and oxygen atoms substitute into the tube wall via the produced ozone molecules. The photoluminescence spectroscopy studies reveal that the obtained SWCNTs exhibit the characteristic spectroscopic features of epoxide-type oxygen-doped SWCNTs. Advantageously, the emission peak of the doped (6, 5) SWCNTs is centered at around 1300 nm, which is most transparent region of biomaterials. We demonstrate immunoassay, fluorescence vascular angiography and observation of the intestinal contractile activity of mice by using the produced oxygen-doped SWCNTs as infrared fluorescent labels and imaging agents.
(Invited) Electron-Donor Behavior of Carbon Nanotubes and Graphene
Authors: Arellano Luis M , Barrejon Myriam , Vizuete Maria , Gomez-Escalonilla María J. , Langa Fernando
Published: February 2020

Carbon nanostructures (CNs) as carbon nanotubes or graphene present unique electronic properties appropriate for the synthesis of custom-made hybrids by functionalization with other electroactive fragments. In this way, the behaviour of CNs as electron acceptor by covalent or supramolecular functionalization of carbon nanotubes and graphene with electron-donating molecules has been object of great interest as the resulting hybrids can be target of interest for solar energy conversion and many CNs-donor hybrids has been described.

Nevertheless, much less work has been devoted to the role of CNs as electron donors by formation of hybrids with strong electron acceptors; in this way, along the last years we have prepared several covalent or supramolecular hybrids between single wall carbon nanotubes, carbon nanohorns or graphene with fullerene derivatives. In this talk, I´ll present our last findings in the synthesis and properties of CN-electron acceptor hybrids.

References

1. M. Vizuete, M. J. Gómez-Escalonilla, J. L. G. Fierro, M, Yudasaka, S. Iijima, M. Vartanian, J. Lehl, J-F Nierengarten, F. Langa, Chem. Commun.,
2011, 47, 12771-12773

2. M. Vizuete, M. Barrejón, M. J. Gómez-Escalonilla and F. Langa, Nanoscale, 2012, 4, 4370-4381.

3. M. Barrejón, M. Vizuete, M. J. Gómez-Escalonilla, J. L. G. Fierro, I. Berlanga, F. Zamora, G. Abellán, P. Atienzar, J.-F. Nierengarten, H. García and F. Langa, Chem. Commun,
2014, 50, 9053-9055.

4. M. Barrejón, H. Gobeze, M. J. Gómez-Escalonilla, J. L. G. Fierro, M. Zhang, M. Yudasaka, S. Iijima, F. D’Souza, F. Langa. Nanoscale, 2016, 8, 14716–14724.
Design and Synthesis of Porphyrin Oligomers and Porphyrinoids Via Suzuki-Miyaura Reaction
Authors: Song Jianxin , Wen Bin
Published: February 2020

In view of multi-porphyrin arrays and new porphyrinoids, whih has potential applications in optoelectronic devices, sensors, photovoltaic devices, non-linear optical(NLO) materials, photodynamic therapy (PDT) pigments, light-harvesting models, and host-guest chemistry. Both the manipulation of interporphyrinic interaction and design of new structural porphyrinods are often essential to achieve desirable electronic and photophysical properties. Recently, the Osuka group developed a transition metal-catalyzed coupling reaction that has been proven to be very useful to construct multiporphyrinic systems. Till now we have adopted this strategy and prepared many heterocycles bridged β-to-β porphyrin arrays, including direct-bridged β-to-β porphyrin nanorings[
1
], earring porphyrins[
3
]. The experiment results indicated that the building blocks will remarkably affect the target molecules. As the bridge is thienylene, the main products is cyclic dimer, trimer, when the bridge is pyridylene, there are trace cyclic products are obtained. when the bridge is free base or Zn(II) porphyrin, bigger loop are formed, while Ni(II)porphyrin is used, the products is much simple. As to synthesis of porphyrin nanobarrel, if the porphyrin monomer is free base or Zn(II) porphyrin, no porphyrin barrel is obtained, which means that only ruffled Ni(II)porphyrin monomers can be used to synthesis porphyrin barrels. Synthesis of direct linked porphyrin nanorings is affected by the meso-substituent on porphyrin, when the substituent is aryl, only trimer and twinned pentamer can be prepared, when the substituent is alkyl, tetramer and twinned heptamer can be obtained.The photophysical study revealed that these porphyrin arrays and porphyrinoids exhibit either longer fluorescent lifetime, larger two photon absorption values or Near-infrared absorptions. Some new porphyrin arrays or porphyrinnoids recently have been constructed through Pd-catalyzed cross-coupling reactions (Figure 1), further study on their properties is underway in our lab.

Figure 1. Crystals of earring porphyrins and multi-porphyrin arrays

References

1. H. Cai, K. Fujimoto, J. M. Lim, C. Wang, W. Huang, Y. Rao, S. Zhang, H. Shi, B. Yin, B. Chen, M. Ma, J. Song, D. Kim, and A. Osuka,
Angew. Chem. Int. Ed
., 2014, 51, 11088-11091.

2.H. Huang, S.-K. Lee, Y. M. Sung, F. Peng, B. Yin, M. Ma, B. Chen, S. Liu, S. R. Kirk, D. Kim, and J. Song,
Chem. Eur. J.
, 2015, 21, 15328-15338.

3. Y. Rao, T. Kim, K. H. Park, F. Peng, L. Liu, Y. Liu, B. Wen, S. Liu, S. R. Kirk, L. Wu, B. Chen, M. Ma, M. Zhou, B. Yin, Y. Zhang, D. Kim, and J. Song,
Angew. Chem. Int. Ed

.
2016, 55, 6438-6442

Figure 1
Tuning the Electrocatalytic Activity of Iron Phthalocyanines for O2 Reduction By the Pull Effect of the Pyridium Axial Ligands
Authors: Zagal Jose H
Published: February 2020

A. Pizarro1, G. Abarca2, J. H. Zagal1, J. F. Silva1, F. Bernardi3, Cristian Gutiérrez-Cerón3, M. Caroli1, Diego Cortés-Arriagada 4, Rubén Oñate, Ingrid Ponce1

1 Facultad de Química y Biología, Universidad de Santiago de Chile. Avenida Libertador Bernardo O’Higgins 3363, Estación Central, Santiago, Chile. 2 Institute of Chemistry, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves, 9500, Porto Alegre, 91501-970, RS, Brazil. Institute of Physics, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves, 9500, Porto Alegre, 91501-970, RS, Brazil. 3 Departamento de Física, Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, Av. Blanco Encalada 2008, Santiago (Chile). 4 Laboratorio de Química Teórica Computacional (QTC), Pontificia Universidad Católica de Chile, Av. Vicuña Mackenna 4860, Macul, Santiago 9900087

Corresponding Author: jose.zagal@usach.cl

We have been able to tune the electrocatalytic activity of iron phthalocyanine (FePc) and iron hexadodecachlorophthalocyanine (16(Cl)FePc) for the oxygen reduction reaction (ORR) by the “pull effect” of pyridinium molecules, which play both the role of molecular anchors and also of and axial ligand for FePc. Pull effect is caused by the positive charge located on the core pyridinium. We have explored the influence of the core positions (Up or Down), in two structural pyridiniums isomers on the activity for the RRO of FePc and 16(Cl)FePc. Of all self-assembled systems tested, the ORR catalytic activity was highest for Au(111)/pyridinium-Up/FePc system. XPS measurements and DFT calculations showed that is possible to tune the FePc-N(Pyridiniums)
and Fe-O2
binding energies, by changing the core positions and affecting “pull effect” in pyridiniums, this has a direct effect on the activity of FePcs. Plot of activity as (log I)E versus the calculated Fe-O2
binding energies gives a volcano correlation indicating that an optimum binding energy of O2 with the Fe center provides the highest activity in agreement with previous findings [1] using MN4s adsorbed on graphite.

Acknowledgements: The authors are grateful to PAI-CONICYT 79150041. Fondecyt 1140192, C.G-C. Fondecyt Postdoctoral Project 3150674. D.C-A thanks ICM grant #120082. Powered@NLHPC: NLHPC (ECM-02). Millennium Project RC120001, Fondecyt 1140199, and Dicyt-USACH, LNLS (Brazil) for the use of beamline (SXS - 18986).

References:

1. Zagal, J. H.; Koper, M. T. M. Angew. Chemie Int. Ed.
2016, 55 (47), 14510–14521.

Figure 1