bluuebunny/crossref_metadata_2025 huggingface dataset:
Using Raman Spectroscopy to Elucidate Conversion in Crosslinked Disulfide Polymers for Lithium-Sulfur Batteries
Authors: Preefer Molleigh B , Seshadri Ram , Wudl Fred
Published: February 2020

The main advantages of Lithium-Sulfur batteries are the high theoretical specific capacity of elemental sulfur and the sustainability of sulfur-based materials over toxic, expensive heavy metals such as cobalt. Sulfur can theoretically achieve 1675 mAh g–1 through a conversion mechanism, but due to the parasitic polysulfide shuttle problem, the capacity rapidly fades. We demonstrate new crosslinked disulfides as promising cathode materials for Li–S cells that are designed to have only a single point of S–S scission, preventing the formation of polysulfides. The first model crosslinked disulfide system we synthesized was designed to maximize the ratio of S–S to the electrochemically inactive framework. The material contains a 1:1 ratio of S:C with a theoretical gravimetric capacity of 609 mAh g–1. Cells made with this crosslinked disulfide cathode material gain capacity through 100 cycles and have 98% capacity retention thereafter through 200 cycles, demonstrating promise for stable, long-term cycling. Coulombic efficiencies near 100% for every cycle, suggesting the suppression of polysulfide shuttle through molecular design. Further iterations of this crosslinked disulfide design aim to increase ionic and electronic conductivities to achieve higher gravimetric capacities that will lead these stable sulfur-based batteries closer to a commercially viable technology. Using crosslinked disulfides as cathode materials in liquid Li–S cells has not previously been explored in detail, so Raman spectroscopy provides an excellent handle to gain mechanistic insight into the conversion processes in these systems. Ex situ Raman confirms the proposed mechanism of disulfide bonds breaking to form a S–Li thiolate species upon discharge and reformation upon charge, and operando Raman provides more detailed understanding of the redox reactions occurring in the cell. Other characterization techniques, such as NMR and XPS provide structural information, in addition to SEM yielding macrostructural information, to piece together a detailed description of the disulfide behavior as a cathode material.

Figure 1
New Opportunities for in Situ and Operando Characterization of Electrochemical Systems at I07
Authors: Mousley Philip , Hussain Hadeel , Rawle Jonathan , Warne Adam , Carla Francesco
Published: February 2020

The range of material systems and architectures used in electrochemical research is vast, spanning from solid-solid electrolyte interfaces for solid state batteries to nano-sized particles systems for electrocatalytic materials in fuel cells. Despite the physical differences among these systems the possibility of establishing relationships between structure and activity is a common key aspect for understanding interfacial electrochemical processes.

I07 is the surface and interface x-ray diffraction beamline at the Diamond synchrotron (Didcot,UK). The beamline exploits a high brilliance 3rd generation synchrotron source to allow the characterization of a wide array of possible sample types, opening up experimental possibilities which are not feasible using standard lab based x-ray sources.

The use of grazing incidence angle techniques available on I07 not only allows reduction of background signal from the bulk enabling measurements of signals from the top layers of a sample, but it also enables investigation of the relationship between nano-scale structural changes and reactivity during time-resolved experiments. The current capabilities of beamline I07 will be outlined regarding in-situ and operando measurements of material systems for applications in energy storage. Also opportunities for investigating novel solid-state electrolyte material interfaces will be detailed. Experimental techniques discussed will include surface x-ray diffraction, x-ray reflectivity, grazing incidence small angle x-ray scattering, grazing incidence wide angle x-ray scattering, and liquid surface x-ray scattering.
Systematic Characterizations of All-Vanadium Redox Flow Battery Employing Pore-Filled Ion-Exchange Membranes
Authors: Moon Ha-Neul , Kim Do-Hyeong , Song Hyeon-Bee , Kang Moon-Sung
Published: February 2020

Recently, the interest in high-performance energy storage system (ESS) is increasing since it is a very essential part of the smart grid for stable and efficient electricity supply. At present, diverse battery technologies such as lithium ion batteries, redox flow batteries (RFBs), and sodium–sulfur batteries are competing with each other to be applied to commercial ESS. Among them, RFBs are considered to be the most promising for a large-scale ESS application. Meanwhile, all-vanadium redox flow batteries (VRBs) utilizing vanadium ions in different oxidation states as the active redox species have been considered as one of the most promising RFBs owing to the controlled crossover rate of the redox species through membranes. Since an ionomer membrane separator is one of the most dominant components determining the charge-discharge characteristics of RFB systems, the development of highly efficient membranes has been considered to be very essential for successful commercialization of VRBs. Among various kinds of membranes, pore-filled ion-exchange membranes (PFIEMs) fabricated by combining a porous substrate and an ionomer are known to have excellent characteristics including high chemical and dimensional stabilities, low manufacturing cost, low mass transfer resistance, etc. In this work, we have developed novel PFIEMs by using a polyethylene (PE)- or a polytetrafluoroethylene (PTFE)-based porous substrate for VRB applications. Especially, we have designed the filling ionomer to possess the high crosslinking degree and ion-exchange capacity, simultaneously. In addition, the prepared PFIEMs and the RFB employing them have been systematically analyzed by various electrochemical methods for evaluating their performances exactly. The detailed results will be presented and discussed at the conference. This work was supported by a grant (No.2017000140002/ RE201702218) from the Environmental Industry Advancement Technology Development Project of Korea Environmental Industry & Technology funded by Korea Ministry of Environment.
Investigation into Mechanical Degradation of Lithium-Ion Batteries with Nickel-Rich Cathode Materials - A Long-Term Cycling Study
Authors: Schweidler Simon , de Biasi Lea , Garcia Grecia , Mazilkin Andrey , Hartmann Pascal , Brezesinski Torsten , Janek Jürgen
Published: February 2020

Layered lithium transition-metal oxides of type LiNi
x
Co
y
Mn
z
O2 (NCM, with x + y + z = 1) are well established and represent the current state of the art cathode materials for different lithium-ion battery applications. The ultimate goal in the area of NCMs is to increase the nickel fraction in the material as much as possible, as this allows for higher specific capacities (for a given charge cutoff voltage). However, recent studies have demonstrated that with increasing practically used capacity the material suffers increasingly from volume changes, eventually leading to mechanical failure. Apart from volume changes, adverse side reactions like structural/morphological changes and/or phase transitions during cycling operation are also possible causes of degradation, affecting capacity retention and overall lifetime of a battery cell. In this work, we report on a long-term study on the structural, electronic and morphological changes of high-nickel NCM/graphite full-cells from operando X-ray diffraction (XRD), scanning electron microscopy, transmission electron microscopy and electrochemical impedance spectroscopy. The acquired data demonstrate that the capacity loss can be attributed predominantly to the cathode side. Using XRD we observed the presence of two differently active NCM phases. However, the NCM cathode material was still found capable of virtually complete Li (de-)lithiation, but with significantly slower kinetics due to, in part, built-up of resistive surface layers with cycling.

Figure 1. a) Charge/discharge profiles of LiNi0.85Co0.1Mn0.05O2/graphite full-cells for various cycles at 1C rate and in the voltage range between 2.8 and 4.2 V. b) Phase fractions of the less and more active NCM phases after charging to 4.2 V (including a 1 h CV step).

Figure 1
(Invited) Complex Ion Migration Mechanisms in Glassy Lithium Solid Electrolytes
Authors: Smith Jeffrey Gordon , Siegel Donald J
Published: February 2020

Sulfur-based glasses have reemerged as promising candidates for use as solid electrolytes in Li-based batteries. Nevertheless, due to their amorphous structure, the ion migration mechanisms that underlie the high Li-ion conductivity observed in these glasses remain poorly understood. The present study employs ab initio molecular dynamics to characterize the local structure and migration mechanisms in the prototype Li-ion conducting glass, 75Li2S–25P2S5. A computational model of the amorphous structure was generated and is shown to closely match the measured neutron pair distribution function. This structure data indicates that Li-ions experience varying coordination environments, with typical Li-S coordination numbers ranging from 3 to 5. Lithium migration is observed to occur via a complex mechanism involving the concerted motion of multiple neighboring lithium ions. Additionally, the PS4 anion sublattice plays an active role in these migration events via the ‘paddle-wheel’ mechanism: Li motion is dynamically coupled to the rotational properties of the PS4 tetrahedra. The behavior of the amorphous phase contrasts with that of the crystalline analogue, where contributions from anion dynamics are limited. These atomic-scale observations suggest that Li-ion transport in S-based glasses results from the combined effects of cooperative cation motion and dynamic anion coupling.
Photoelectrochemical and Surface Analysis of CdSe/Poma Hybrids Deposited on Gold, Platinum, and HOPG Electrodes
Authors: Dulovic Stephanie , Casto Sophia Maria , Widera Justyna , Maranowski Bartosz , Strawski Marcin , Szklarczyk Marek
Published: February 2020

Research of semiconductors have increased in popularity over the past decades because of their applications in electronics, biomedical devices, photoelectrochemical cells, and detoxification of organic waste.

This study intended to analyze the stability and photoefficiency of the semiconductor hybrid consisting of cadmium selenide and poly(o-methoxyaniline) (CdSe/POMA) deposited on various electrode surfaces, such as: Au, Pt and highly organized pyrolytic graphite (HOPG). The formation of the CdSe/POMA composite on HOPG involved electrochemical deposition of CdSe film for 20 cycles, followed by POMA polymerization for 5 cycles using in both cases cyclic voltammetry method. The potential range of CdSe deposition, from the solution of 5 mM CdSO4 and 1 mM SeO2 in 0.1 M HClO4, was varied depending on the type of the electrode surface: HOPG (0 V to -1.2 V), Pt (0.345 V to -1.1 V), Au (0.4 V to -1.1 V). The chronoamperometric deposition of CdSe was also explored on HOPG, with the deposition occurring at a constant -1.045 V for 32 minutes. The polymerization of POMA was carried out at 50 mV/s from -0.2 V to 0.8 V from the solution of 0.06 M o-anisidine in 0.1 M HClO4.

The photoelectrochemical studies of the created composites were performed in the 0.1M Na2SO3 solution using cyclic voltammetry, open circuit potentiometry (OCP), and chronoamperometry. The chronoamperometric deposition of CdSe on HOPG had a smaller response to light with (9 μA/cm2) of photocurrent, suggesting it was less successful than CdSe film on HOPG (22 μA/cm2) obtained by cyclic voltammetry. Therefore, the deposition of CdSe/POMA via cyclic voltammetry was further used for the deposition studies on HOPG, Pt, and Au. The electrode system that produced the largest photopotential of 250 mV was CdSe/POMA/Au, while on Pt (230 mV) and HOPG (220 mV) being slightly smaller. However, the CdSe/POMA/HOPG system presented much faster response time than the composite deposited on Au or Pt, suggesting that this system was more easily stabilized. The chronoamperometric studies observed the greatest photocurrent density for the composite deposited on Au with 50 μA/cm2, while HOPG (17 μA/cm2) and Pt (6 μA/cm2) had smaller current densities. Following photostudies, the surface morphology and composition of CdSe/POMA on the various electrodes were analyzed using X-ray Photoelectron Spectroscopy (XPS), Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). The surface analysis of the samples before and after photo-studies found that degradation occurred as a result of exposure to light. The degradation of CdSe/POMA composites deposited on Au and Pt was visibly greater in comparison to the CdSe/POMA on HOPG.
Characterization of Layered Rocksalt Type Cathode/Sulfide Solid-Electrolyte Interface Using a Model Film Battery and in Situ X-Ray Diffraction
Authors: Takano Ryoma , Hirayama Masaaki , Quan Zhen , Kanayama Takamasa , Suzuki Kota , Kanno Ryoji , Tamura Kazuhisa
Published: February 2020

Sulfide based ionic conductors are attractive solid electrolytes for all solid-state batteries owing to their high ionic conductivity and high reliability. One of remaining issues is to stabilize the lithium (de)intercalation reaction at the cathode/sulfide electrolyte interface in high potential regions for the development of all solid state batteries with high energy density. Here we investigated the interfacial reactions between LiMO2 (M= Ni, Mn, Co) and amorphous Li3PS4 using a model film battery. LiMO2 cathode/LiNbO3 buffer layer/Li3PS4 films were fabricated by pulsed laser deposition, and Li metal anode was deposited by vapor deposition. The thin-film battery had a well defined interface suitable for elucidating electrochemical reactions. The relationship between electrochemical properties and crystal structural changes were discussed based on crystal structures determined by in situ X-ray diffraction (XRD) measurements conducted under high voltage operation.
3D Electrode Design: Additively Manufactured 3D Architectured Nanocrystalline Nickel and Nickel Copper Structures
Authors: Schürch Patrik , Pethö Laszlo , Michler Johann , Philippe Laetitia
Published: February 2020

Imposing a well defined geometrical shape to an electrode is a suitable way for increasing surface area, as well as optimising the mass transfer phenomenon. By combining electrodeposition with two-photon lithography templates, it is possible to create free-form microscale 3D metal architectures with almost complete freedom. This work features nickel and nickel copper, as the electrodeposition of these materials is well studied and they are frequently used catalysts for oxygen and hydrogen evolution reaction (OER and HER).

Control over the electrodeposition of nickel and nickel copper into the complex templates was achieved by creating 3D time-dependent electrodeposition simulations to predict the optimal experimental conditions and deposition parameters. The simulations are based on various electrochemical measurements of the two systems, such as rotating disc electrode measurements, cyclic volatammetry and chrono-potentiometry. An additional benefit of the simulations is that it can be used prior to the experiment to determine the feasibility of a given design to be electrodeposited.

We successfully deposited various 3D architectured electrode microstructures made of nickel and nickel copper.
Trimetallic Carbon-Supported Catalysts for Borohydride Oxidation and Oxygen Reduction in Alkaline Solutions
Authors: Elsheikh Ahmed MAA , Oliveira Raisa Costa Paes , Sljukic Biljana , Santos Diogo M.F. , Sequeira Cesar A.C. , McGregor James
Published: February 2020

Borohydrides present a particularly attractive option for alkaline liquid fuel systems, having high energy densities, a low standard potential for its oxidation, and good stability in alkaline conditions. A key area in the success of a fuel cell utilizing borohydride is the development of an anode, which can make use of the full 8-electron oxidation, directly oxidising the borohydride with as little of the undesired hydrolysis reaction occurring as possible. This is in addition to the common requirements of high activity, high stability, good electronic conductivity and effective transport of reactants and products. Here we present new studies on the oxidation of borohydride and reduction of oxygen in alkaline media under various conditions for a selection of trimetallic carbon-supported catalysts based on Pd, prepared by quick and straightforward synthetic routes. The prepared catalysts were characterised by cyclic voltammetry, chronoamperometry, and RDE based procedures. Notably, PdAuNi/C prepared via a NaBH4-2-propanol complex presents highly dispersed trimetallic alloy particles, as determined by XRD, XPS and TEM. The best performing electrodes under characterisation conditions were tested in a direct borohydride fuel cell under several different conditions. The influence of experimental parameters (temperature, borohydride concentration, as well as NaOH concentration) on the electrical behaviour of the fuel cell were studied and optimized. These results show that Pd-based trimetallic catalysts supported on carbon provide a ready route to successfully operate borohydride based fuel cells.

Acknowledgements: A. Elsheikh acknowledges a Newton-Mosharafa Scholarship (Reference no. NMJ8/15) for funding. The Portuguese Foundation for Science and Technology (FCT, Portugal) is acknowledged for PhD grant no. SFRH/BD/137470/2018 (R.C.P. Oliveira), contract no. IST-ID/156/2018 (B. Šljukić) and contract no. IF/01084/2014/CP1214/CT0003 under IF2014 Programme (D.M.F. Santos).

Keywords: Palladium, trimetallic catalysts, nanomaterials, borohydride oxidation, oxygen reduction, fuel cell, kinetic parameters.
Flowable Semi-Solid Electrodes with Superconcentrated Electrolytes: An Electrochemical Impedance Study
Authors: Poli Federico , De Giorgio Francesca , Soavi Francesca
Published: February 2020

Flow lithium batteries (FLB), featuring semi-solid anolyte and/or catholyte, and flow supercapacitors (FSC) working with flowable slurries of high surface are carbons, are emerging technologies in the energy storage scenario. Unlike conventional lithium batteries and supercapacitors, flow cells enable energy and power decoupling which is of great interest for system modularity.

The use a flow configuration was also demonstrated to improve current and power output performance of lithium/oxygen batteries by enhancing oxygen mass transport to the cathode.

The common requirement of FLB and FSC is that the flowable electrodes feature an effective percolating network. This is needed to achieve fast charge/electron transfer within the powders in the catholyte or anolyte and between the slurries and the current collectors.

Carbon particles are often used to improve slurry conductivity. The morphology of the carbon particles, their concentration and interaction with the electrolyte carrier greatly impact on the electronic percolating network, and, then, on the cyclability of the flowable electrodes

Here we report about an electrochemical impedance spectroscopy (EIS) study of carbon-based slurries featuring TEGDME-LiTFSI electrolyte. We demonstrate that moving from conventional to superconcentrated electrolytes has a structuring effect on the distribution of carbon particles of the slurry which improves the electronic percolation network, and, hence, charge transfer processes in flowable cells. This study aims at demonstrating EIS as a powerful and simple technique for the design of new formulations of advanced flow batteries and supercapacitors.

References

[1] A. Narayanan, D. Wijnperlé, F. Mugele, D. Buchholz, C. Vaalma, X. Dou, S. Passerini, M.H.G. Duits, Electrochim. Acta 251 (2017) 388–395.

[2] I. Ruggeri, C. Arbizzani, F. Soavi, Electrochim. Acta 206 (2016) 291–300.

[3] Ruggeri, Irene, Catia Arbizzani, and Francesca Soavi. "Carbonaceous catholyte for high energy density semi-solid Li/O2 flow battery." Carbon 130 (2018): 749-757.

[3] Q. Huang, Q. Wang, ChemPlusChem 80 (2015) 312 – 322. [4] M. Duduta, B. Ho, V. C. Wood, P. Limthongkul, V. E. Brunini, W. Craig Carter, and Y.-M. Chiang, Adv. Energy Mater. 1 (2011) 511–516.

[4] L. Morici, F. De Giorgio, F. Poli, A. Brilloni, F. Soavi, 69th Annual Meeting of International Society of Electrochemistry (ISE), Bologna (Italy), 02-07/09/2018.
Onset of Dendritic Li Electrodeposition: Experimental and Modeling Studies Highlighting the Critical Role of Li+ Transport within the SEI Layer
Authors: Maraschky Adam , Akolkar Rohan
Published: February 2020

High-energy density batteries are essential for powering future electric vehicles. One major hurdle to the progress in developing rechargeable energy-dense Li-metal batteries is the dendritic electrodeposition of Li during the battery charging process. In this contribution, we report on our investigations of the onset time for dendritic growth during galvanostatic electrodeposition of Li metal. Using a combination of electrochemical and optical microscopy techniques, we observe that Li dendrites initiate at a time when the surface overpotential during galvanostatic electrodeposition reaches a local maximum value. This observation is explained using an analytical transport model. Within the framework of this model, the Li+ concentration within the solid electrolyte interphase (SEI) at the Li–SEI interface decreases gradually as the SEI becomes thicker over time. At the dendrite onset time (τonset), the Li+ concentration at the Li–SEI interface approaches zero. Due to such Li+ depletion, surface roughness on the Li electrode amplifies, eventually producing dendrites. Once dendrites form, they rupture the SEI, which then lowers the surface resistance for Li plating. Model predictions of how τonset varies with current density and electrode soak time are found to be in qualitative agreement with experimental observations. Support for this model is gained by the application of pulsed currents, which mitigate Li+ concentration depletion within the SEI, delaying or preventing the formation of dendrites. The effect of temperature on τonset is also investigated and discussed within the framework of the transport model.

Figure 1
Solid-Electrolyte-Interphase Formation and Effects on Li Metal Anodes
Authors: Balbuena Perla B.
Published: February 2020

Theoretically, lithium metal anodes are the optimal negative electrodes. In practice, several obstacles arising from the extreme lithium reactivity limit their applications. The surrounding environment in principle can modify lithium electronic structure, which determines its reactivity. For this purpose, a variety of electrolyte chemistries (liquid, solid, polymer, gel) have been and are continuously tested. Moreover, the solid-electrolyte interphase (SEI) that results from electron transfer from the anode to the electrolyte is usually a multicomponent film expected to exert a protective role controlling the high reactivity of the anode. The SEI is extremely sensitive to the chemistry of the electrolyte, but also to the structure of the anode. Here we discuss how the electrolyte chemistries affect SEI formation and Li metal nucleation, for typical liquid and solid electrolytes. Our first-principles analysis is complemented with experimental in situ observations.
Experimental Parameterization of a Pseudo Two-Dimensional (P2D) Model for Lithium Ion Batteries: A Study of a Commercial Cell
Authors: Chen Chang-Hui , Lain Michael J , Widanage Widanalage Dhammika , Kendrick Emma
Published: February 2020

Modelling of lithium ion batteries is important, as it provides a way to predict their performance under various operating conditions, as well as the state of health during cycling, thereby providing key guidance in the designing of these devices. Among the numerous models studied in literature, the pseudo two-dimensional (P2D) model developed by the Newman group, is one of the most widely adopted lithium-ion battery model.1 To build a precise P2D battery model with predictive value, one crucial part is parameterization. However, accurate measurement of such complex physical and chemical processes is challenging and existing literature data is incomplete at best.2 In this contribution, we adapt and demonstrate an experimental procedure to determine a complete set of parametric inputs required for a P2D model with reduced order. Designing the experiments with the model explicitly in mind, allows us to identify the crucial inputs, to able the model to capture the existing system accurately as well to use it as a predictive tool for the design of new systems.

Experimental results presented herein are based on a commercially available cylindrical cell from LG Chem. (M50), of which the design and material content is unknown. The electrodes were extracted from this commercial cell to enable material characterization. The physical and chemical parameters of the electrodes and cells were investigated; the chemical and structural properties analysed with X-ray diffraction, electron microscopy and inductively coupled plasma – optical emission spectroscopy (ICO-OES) techniques. The electrochemical properties such as the electronic and ionic conductivities were analysed in small test coin and Swagelok™ cells with extracted electrodes under different charging and relaxation conditions.

References:

Fuller, T. F.; Doyle, M.; Newman, J., Simulation and Optimization of the Dual Lithium Ion Insertion Cell. 1994,
141 (1), 1-10.

Jokar, A.; Rajabloo, B.; Désilets, M.; Lacroix, M., Review of simplified Pseudo-two-Dimensional models of lithium-ion batteries. Journal of Power Sources
2016,
327, 44-55.

Figure 1
Ionic Liquids-Promoted Utilization of Redox-Active Organic Materials for Flow Batteries
Authors: Chen Ruiyong , Huang Zhifeng , Zhang Peng , Henkensmeier Dirk , Hempelmann Rolf
Published: February 2020

Redox flow batteries (RFBs) are regarded as technique-of-choice for load levelling and peak shaving for the utilization of renewable energy sources, and are key component in smart grid network.[1,2] Electrolyte chemistry is a key consideration for the performance enhancement.[3-9] The conventional RFBs using non-organic redox species in aqueous H2SO4, KOH and NaCl, with limited operating voltage and volumetric energy density. Development of new high-performance electrolytes is highly important for speeding up the market penetration of RFBs. Herein, we explore the feasibility of using “water-in-ionic liquid” supporting electrolytes for tailoring the properties of electrolytes, including the electrochemical stability window, temperature adaptability, solubility of redox-active organics and chemical/electrochemical stability and reversibility of active materials.

References:

[1] R. Chen, ChemElectroChem (2018) doi: 10.1002/celc.201801505.

[2] R. Ye, D. Henkensmeier, S. J. Yoon, Z. Huang, D. K. Kim, Z. Chang, S. Kim, R. Chen, J. Electrochem. En. Conv. Stor.15 (2018) 010801.

[3] R. Chen, R. Hempelmann, Electrochem. Commun. 70 (2016) 56-59.

[4] Y. Zhang, R. Ye, D. Henkensmeier, R. Hempelmann, R. Chen, Electrochim. Acta 263 (2018) 47-52.

[5] Z. Chang, D. Henkensmeier, R. Chen, ChemSusChem 10 (2017) 3193-3197.

[6] A. Tatlisu, Z. Huang, R. Chen, ChemSusChem 11 (2018) 3899-3904.

[7] R. Chen, D. Henkensmeier, S. Kim, S. J. Yoon, T. Zinkevich, S. Indris, ACS Appl. Energy Mater. 1 (2018) 6047-6055.

[8] R. Chen, R. Ye, R. Hempelmann, S. Kim, A. Möller, J. Hartwig, N. Krawczyk, P. Geigle, Patent application: PCT/EP2018/056087, 2018.

[9] Z. Chang, D. Henkensmeier, R. Chen, J. Power Sources, in revision.

[10] Z. Huang, P. Zhang, X. Gao, D. Henkensmeier, S. Passerini, R. Chen, submitted.
NiMoO4 Nanocluster Carbon Composite for High Performance Asymmetric Supercapacitors
Authors: Sharma Gyan Prakash , Pala Raj Ganesh , Sivakumar Sri
Published: February 2020

Faradaic redox reaction governed with pseudocapacitance mechanism are better as compared to intercalation mechanism as it overcomes the diffusion limitations and results in improved power density. Further, the life cycle expectancy improves due to fast surface redox reactions. Metal oxides with battery behaviour are the best choice for pseudocapacitance by increasing surface to volume ratio. This can be achieved by synthesizing ultrasmall nanocluster of material. To this end, we report a facile synthesis of ultrasmall NiMoO4 nanoparticle on active carbon with high specific capacity and long-term cycle stability. The ultrasmall NiMoO4-active carbon composite (NiMo@AC) sample shows specific capacity of 665 C/g (1662.5 F/g or 184.7 mAh/g) at current density of 1 A/g. An asymmetric supercapacitor fabricated from NiMoO4@AC nanocomposite displayed specific capacity of 131.5 C/g (87.7 F/g or 36.5 mAh/g), energy density of 27.4 Wh/Kg and a power density of 184W/Kg at a current density of 1 A/g. This high capacity can be attributed to the improved specific area of electroactive material. The fabricated supercapacitor retains ~92% of initial capacity after 4000 cycles. Active carbon not only provide better dispersion to nanoparticle, but also contribute towards the structural stability due to embedment of the particles into the carbon matrix. The results indicate that NiMo@AC nanocomposite is a potential candidate for electrochemical energy storage.

Figure 1
In Situ Growth of Nife Alloy Nanoparticles Embedded into N-Doped Bamboo-like Carbon Nanotube As a Bifunctional Electrocatalyst for Zn-Air Battery
Authors: Bin Duan , Xia Yong-Yao , Yang Beibei , Wang Yong-Gang
Published: February 2020

Developing low-cost catalysts for electrochemical oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) with superior performance in alkaline solution is of significance for large-scale application in aqueous zinc-air batteries (ZABs). Herein, we describe in situ design of embedded NiFe nanoparticles into the N-doped bamboo-like carbon nanotube (NBCNT) with high catalytic performance and stability. The obtained NiFe@NBCNT hybrid exhibits a high electrochemical activity and stability with an unexpectedly low overpotential of ~195 mV for OER at 10 mA cm-2, and an onset potential at 1.03 V for ORR, superior to the state-of-the-art Pt/C and RuO2 catalysts. Additionally, compared to the mixture Pt/C and RuO2 cathode, the ZAB based on the NiFe@NBCNT cathode displays lower overpotential (0.80 V), higher stable round-trip efficiency (58.3%) and improved power density for 200 cycles at 10 mA cm-2. Apparently, the obtained results indicate that NiFe@NBCNT hybird is proven to be one of the best non-noble metal catalysts for achieving commercial implementation of rechargeable ZABs.
Increasing Energy Density and Power Density in Hybridised Supercapacitor-Battery Devices
Authors: Lekakou Constantina , Baboo Joseph Paul , Markoulidis Foivos , Slade Robert CT
Published: February 2020

Research is presented aiming to increase both power and energy density of lithium batteries by applying composite cathodes containing sulphur, which has a high theoretical specific capacity of 1675 Ah/kgS and is an abundant and low-cost material, and increase the power density of the cells by creating battery-supercapacitor hybrids with the hybridisation carried out at electrode material level.

The focus of current research worldwide has been to increase the cyclability of lithium-sulphur (Li-S) batteries, which has been accomplished by devising composite sulphur cathodes, to avoid cathode degradation due to the expansion of sulphur to accommodate the formation of sulphides, and various functionalisation approaches to trap the sulphides and avoid the ‘shuttle’ effect during charge. However, the theoretical capacity of sulphur has not been achieved even at first discharge, lowering the expected energy density, and this is further compounded by the fact that only a fraction of the composite cathode is sulphur. Modelling studies have shown that access of all sulphur by the Li+ ions in the micropores is critical and formation of sufficient amounts of higher order sulphides during the first stage of discharge is needed, to be able to obtain a long second stage discharge plateau. The first stage of our study is focused on demonstrating homogeneous and deep sulphur impregnation of porous carbonaceous material to create cathodes with more than 50 wt% sulphur in a supercapacitor-type, porous, host matrix. Repeated discharges are carried out after which we have achieved the theoretical specific capacity of sulphur at first discharge (cumulative curve in Figure 1). We shall continue with parametric studies to investigate the effect of different amounts of sulphur in the composite cathode on the pore size distribution and discharge capacity.

The second part of this study includes the investigations into lithium battery-supercapacitor cells hybridised at electrode material level, in combinations of parallel and in series material parts in equivalent circuit models. The effect of the supercapacitor porous carbonaceous electrode materials on the voltage of the cell in galvanostatic charge-discharge curves will be presented in experimental investigations for half-cells of both sides and full cells. Some novel cell architectures will be presented aiming at minimising any detrimental reactions in the supercapacitor materials within the battery cell window.

Figure 1
Synthesis and Application of Spent Tea Leaves As the Sulfur Cathode for Lithium Sulfur Battery
Authors: Arie Arenst Andreas , Kristianto Hans , Demir-Cakan Rezan
Published: February 2020

Sulfur is able to react with Li in reversible reaction to form Li2S in the lithium sulfur battery configuration. The theoretical capacity of lithium sulfur battery is about 1672 mAh/g which is higher than the capacity of conventional Li-ion batteries. However, there are some problems should be overcome for the utilization of sulfur cathodes. It is common to use of carbon as the matrix to host sulfur cathodes and increase the conductivity. Previously, numerous carbons with specific morphology and porosity have been used. The presence of porous structures is believed can be able to facilitate the homogeneous infiltration of sulfur on the carbon pore structures and improves the connectivity between carbon and sulfur components. Generally, the synthesis process of carbon materials is very complex that cause the large scale production is expensive and difficult. Here, porous carbon was synthesized from biomass waste spent tea leaves by hydrothermal carbonization and ZnCl2 activation process. Hierarchical porous carbon with high surface area (1875 m2/g) and pore volume (1.15 cm3/g) was obtained at ZnCl2/carbon ratio 0f 4.0 and activation temperature of 800 C. As-obtained porous carbons were then utilized as as composite sulfur cathodes for Lithium Sulfur battery. The porous structure permits sulfur loading of 59.5 wt% to be diffused into the carbon host. The carbon-sulfur composite electrodes exhibited the electrochemical performance by showing an initial specific capacity of 1048 mAhg-1 at 0.05 C and maintained specific capacity of 627 mAhg-1 after 100 cycles. Furthermore it had good capacity retention of 428 mAhg-1 at 0.5 C even after 100 cycles, which reveals its promising roles as sulfur cathodes in lithium sulfur batteries.
(Invited) Sulphide Electrolytes with Lgps Structure– Combination with Anode Materials
Authors: Hori Satoshi , Suzuki Kota , Hirayama Masaaki , Kanno Ryoji
Published: February 2020

The all-solid-state batteries offer an attractive option owing to their potential in improving the safety and achieving both high power and high energy densities. The solid electrolyte is a key issue for the development of all-solid-state batteries. Although high ionic conductivity has been achieved for the sulfide electrolyte system, metal anodes are necessary for the electrode selection to improve the energy density of the batteries. Stability of the electrolytes to low voltage region vs. lithium is an important factor for the use of this purpose. Among the sulphide electrolytes proposed, the LGPS (Li10GeP2S12) family exhibits high bulk conductivity of over 10-
2 S cm-1 at room temperature and has a wide variety of compositions, which provide various conductivity and stability characteristics. The present study reviews the materials of the LGPS-type solid electrolytes and the reactions with metal anode systems.
Study of the Lithium Ion Transfer Mechanism in Composite Electrolyte By Solid State Li NMR
Authors: Li Meirong , Frerichs Joop Enno , Hansen Michael Ryan , Winter Martin , Bieker Peter
Published: February 2020

Ceramic-polymer composite electrolytes promised to provide high conductivity with certain flexibility, while the inherent differences of ceramic and polymer electrolyte made the lithium ion transfer mechanism in composite electrolyte controversial. In this work, we fabricated composite electrolyte of Li10GeP2S12 (LGPS) and polyethylene oxide (PEO) within different composition, the ionic conductivity and electrochemical performance were compared and studied. By applying high-resolution solid-state Li NMR, the lithium ion pathway in these composite electrolytes can be tracked to reveal the ionic transport mechanism. This study can provide insights in compositional design of the composite electrolyte for applying in all solid state batteries.
Novel Electrolyte Systems for Improving Energy Density and Power Density of Li-O2 Batteries
Authors: Yu Aishui
Published: February 2020

Capacities and power density of Li-O2 batteries are closed contacted with physical properties of electrolyte. In this work, we research the electrochemical performance of the mixed electrolyte between dimethylsulfoxide (DMSO) and N, N-dimethylacetamide (DMA), firstly. The cell with 70% of DMA mixed electrolyte exhibited high discharge rate capability and low over-potential that the charge platform is below 3.6V at a current density of 0.2 mA cm-2. The titration result showed that DMA is more stable than DMSO in Li-O2 batteries. It is because that the stability of high donor number (DN) solvent is less than that of the low DN solvent in Li-O2 batteries, even though high DN solvent has a high discharge capacities. 1, 2

Based on this, we proposed a new strategy; namely, by combining a relative stable solvent with low DN and a stable additive as the cell electrolyte, the relationship between high capacity and high stability could be balanced. A novel type electrolyte additive, octamethylcyclotetrasiloxane (OMTS), is applied to Li-O2 batteries with TEGDME-based electrolyte with low DN. The electrochemical tests show that, With an optimal OMTS content (10% OMTS), the cell displayed a discharge capacity of 6778 mAh g-1 at 0.05 mA cm-2, and its discharge capacity still has an acceptable capacity of 1823mAh g-1 at an ultra-high current density of 1 mA cm-2. Specially, the capacity retention of the cell with optimal OMTS content is more than double that of the cell with no OMTS additive at large current density of 1 mA cm-2. The further NMR and Li2O2 yield measurements during discharge indicate that OMTS additive does not alter the discharge product and compromise the stability of electrolyte.

Figure 1
Enzymatic Biofuel Cells
Authors: Safari Tahereh
Published: February 2020

Biofuel cell can be defined as a device that can directly change chemical energy into electrical energy through electro biochemical reactions. In other words, in these kinds of cells, biocatalysts that can be either enzymes or microorganisms or cells, are used for producing electrical energy. In biofuel cells, biocatalysts are used in the following two ways:

Biocatalysts can produce fuel substrates necessary for fuel cell through bio catalytic exchanges or metabolic processes.

Biocatalysts can participate in the electron transmission chain between fuel substrates and electrode level.

On this basis biofuel cells can be divided in two groups of microbe based cells and enzyme based cells.

In this paper, we describe the following titles about enzymatic biofuel cells:

Performance of enzymatic biofuel cells

A view of the methanol/oxygen enzymatic biofuel cell

View of an electrode lactate dehydrogenase enzyme

Replacement of apo-glucose oxidase surface on a gold electrode layered with PQQFAD.

Bio-electrolytic cathodes of material cyt / cox

Biodegradable fuel cells based on enzymes layered electrodes Examples of biofuel cells:

Biodegradable fuel cell based on pyrroloquinoline and Micro Oxidase 11 layered electrodes

View of a biofuel fuel cell based on NADH , H2O2

Biofuel cell based on glucose oxidase and micro peroxidase-11 electrode

View of a fuel cell based on H2O2 glucose

View of biofuel fuel cell No compartment

Thermodynamic parameters in biofuel cells

Reinforced wireless transmission system (power supply) by an enzyme biofuel cell grown in an orange

Experiment in place with growing oranges

Mathematical equations governing

Biofuel cell implant in the body of animals
Self-Assembled Monolayers of Vitamin B12 over N-Doped Graphene: A Promising Electro-Catalyst for Hydrogen Evolution and Electro-Oxidative Sensing of H2O2
Authors: Bhat Mohsin A , Bhat Sajad A
Published: February 2020

The redox, chemical and biochemical characteristics of molecular hydrogen (H2) and hydrogen peroxide (H2O2) promise sustainable, economically and environmentally friendly means to address some serious global issues related to energy, environment and human health. However, the non-availability of a cheap, efficient and durable electrocatalyst continues to hamper the practical exploitation of H2 and H2O2 as solution to these challenges. In the work to be presented, we shall present a simple strategy for the self-assembling of Vitamin B12 (Vit.B12) over nitrogen-doped graphene (NGr) for fabrication of Vit.B12-NGr nanohybrids; an electrochemically stable, reusable electrocatalyst with an excellent prospect for hydrogen evolution reaction (HER) and non-enzymatic electro-oxidative sensing of H2O2. Through the data recorded for the characterization of the Vit.B12-NGr nanohybrids through various techniques it shall be clearly proven that the conceived method ensures the self-assembling of Vitamin B12 as a monolayer over N-Gr. Results from our detailed voltammetric investigations over the Vit.B12-NGr modified electrodes besides establishing the redox accessibility, stability and enhanced activity of Co(II) centres in Vit.B12-NGr composites also suggest that the presence of NGr in Vit.B12-NGr composite not only assists the directed ET to Vit.B12, but it also improves the stability of the resulting composite by minimizing its loss to the solution phase.

Results from our electrocatalytic investigations clearly demonstrate the excellent stability and electrocatalytic activity of Vit.B12-NGr nanohybrid towards HER (Figure 1). For HER, the Vit.B12-NGr nanohybrid displays onset potential of -0.096 V vs RHE, a low Tafel slope of ca. 68.3 mV/dec and an overpotential requirement of just -0.210 V for 10 mAcm-2. Moreover, we shall present results from our electro-sensing investigation that establish that the Vit.B12-NGr is a promising electrocatalytic surface for the electro-oxidative sensing of H2O2. In our investigations we observed that use of Vit.B12-NGr ensures the H2O2 sensing with a sensitivity of 430 µA/mM (8.775 µAmM-1cm-2) and a limit of detection as low as 0.02 µM. These HER activity and H2O2 sensing parameters displayed by Vit.B12-NGr are either superior or comparable to those observed for the various recently reported state-of-the-art HER electrocatalysts and H2O2 sensors.

Figure 1.
HER performance at various electrodes
(A)
LSV polarization curves (negative direction) of bare-GCE (black line), NGr/GCE (red line), Vit.B12-NGr/GCE (blue line) and Pt/C (green dotted line)in 0.5 M H2SO4 with scan rate 100 mV/s.
(B)
The corresponding HER Tafel plot of NGr/GCE, Vit.B12-NGr/GCE and Pt/C.
(C)
LSV curves on Vit.B12-NGr/GCE surface at the ﬁrst cycle (black) and after 50 cycles (red dotted) (scan rate 100 mV/s).

Figure 1
Bilateral Atypical Facial Pain Caused by Eagle’s Syndrome
Authors: Anuradha V. , Sachidananda Ravi , Pugazhendi Satish Kumaran , Satish Preeti , Navaneetham Romir
Published: February 2020

Recurrent throat pain, “foreign body” sensation, difficulty in swallowing, or vague facial pain is many times caused by the presence of an elongated styloid process. Many times, this condition is misdiagnosed and the patient is treated for facial neuralgia. But once Eagle’s syndrome is confirmed by clinical and radiological examination, the treatment is always surgical resection. The approach maybe intraoral or extraoral. In this paper, we present a case of Eagle’s syndrome caused by bilateral elongation of the styloid process and where surgical resection of the same gave instant permanent relief for the patient.
Assessment of the Implementation of Critical Pathway in Stroke Patients: A 10‐Year Follow‐Up Study
Authors: Jang Yun Jeong , Park Dahye , Kim Hyeong Seop , Lee Chang Han , Byun Ha Young , Yoon Chul Ho , Lee Eun Shin , Shin Heesuk , Chun Se-Woong , Lim Seung-Kyu , Oh Min-Kyun
Published: February 2020

Background. The complications after stroke inhibit functional recovery and worsen the prognosis of patients. The implementation of a critical pathway (CP) can facilitate functional recovery after stroke by enabling comprehensive and systematic structured rehabilitation. Objective. To evaluate the effects of the implementation of CP in stroke patients for 10 years. Methods. The data were collected from 960 patients who were diagnosed with a stroke at the university hospital emergency room, who were transferred to the rehabilitation center after the acute phase, and who were discharged after undergoing comprehensive rehabilitation. Based on data collected over a period of 10 years, changes in demographic and stroke characteristics, preexisting medical conditions, poststroke complications, and functional states, as well as length of stay (LOS), were evaluated before and after CP implementation. The modified Rankin Scale (mRS) and the Korean version of the Modified Barthel Index (K‐MBI) were used to evaluate functional states. Results. There were no significant differences in demographic and stroke characteristics before and after CP implementation. For those with preexisting medical conditions, there was no significant difference between before and after CP implementation. The majority of the complications were significantly decreased after the implementation of CP. Except for hemorrhagic stroke patients, the Brunnstrom stage in the ischemic and total stroke patients after CP implementation was significantly increased in the upper and lower extremities. The total hospitalization LOS and rehabilitation center hospitalization times were significantly reduced in ischemic and total stroke patients. There was no statistically significant difference in the functional gain of K‐MBI and the efficiency of rehabilitation between before and after CP implementation. Conclusion. The implementation of CP allows for better application of evidence‐ and guideline‐based key interventions and helps to provide early, comprehensive, organized, and more specialized care to stroke patients. Despite limited evidence, CP is still recommended as a means of promoting best practices in hospital care for stroke patients.