bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nitrogen-Enriched, Nanostructured Carbon Materials for Application in High-Loading Lithium-Sulfur Cathodes
Authors: Schneider Artur , Brezesinski Torsten , Sommer Heino , Janek Jürgen 
Published: February 2020

The development of efficient energy storage systems is of exceptional importance considering the increasing demand in electrical energy for both, stationary and mobile applications. Among a wide range of possible cathode materials elemental sulfur has the highest theoretical capacity of 1675 mAh/g which makes it a promising candidate as a positive electrode material.[1] However, the poor cycle life and rate capability of sulfur cathodes have limited the practical application of this attractive technology. Sulfur is highly electronically and ionically insulating which makes the use of conductive additives such as carbon black inevitable. Polysulfides, being generated during cyclization, dissolve in the liquid electrolyte and shuttle between the anode and cathode to react chemically and cause a loss of active material. Furthermore, the final product of the sulfur reduction, Li2S, is highly insulating and partially responsible for the rising electrode resistance during cycling. Precipitation of solid lithium sulfide is assumed to proceed both, on cathode and on anode side.
Different carbon materials are widely used as cathode additives as they offer a high electronic conductivity coupled with low mass and a high surface area.[2] Recently, significant progress has been achieved using structured meso- and microporous carbons as host materials for sulfur. In order to prevent the loss of active material by dissolution, the conductive matrix is assumed to constrain the highly soluble polysulfide inside the cathode by chemical or physical interactions. Therefore, the parasitic polysulfide shuttle and undesired side reactions with the lithium anode can be mitigated. Moreover, structured carbons have a stabilizing impact on the structural integrity of the cathode matrix, as they are able to compensate the mechanical stress arising from the volume expansion during the chemical conversion of sulfur into lithium sulfide. [3]
Here, we present novel, nitrogen-enriched, nanostructured carbons (MPC) as cathode materials for lithium-sulfur batteries. Synthesized via hard-template approach, the obtained materials exhibit a well-defined mesoporous structure with a nitrogen content of approx. 10 %, enabling the possibility of sulfur infiltration. Due to a high specific surface area (400 – 500 m2/g), enhanced polysulfide adsorption and good mechanical stability, cathodes with a high active material loading (above 2 mg/cm2) and improved cycling performance can be fabricated.
Significantly improved specific and areal capacities were achieved over 200 cycles with an increased sulfur loading. It can be shown that the synergetic effects of sulfur confinement and carbon modification can crucially improve the performance of lithium-sulfur batteries.

References

[1] Manthiram, A., Acc. Chem. Res., 2013, 46, 1125–1134
[2] Ji, X. L.; Nazar, L. F. Nat. Mater. 2009, 8, 500–506.
[3] Sun, F. ACS Appl. Mater. Interfaces, 2013, 5, 5630–5638
Thermodynamic Analysis of Lithium Storage at Abrupt Junctions: Modeling and Experimental Evidence
Authors: Chen Chia-Chin , Fu Lijun , Samuelis Dominik , Maier Joachim 
Published: February 2020

Besides conventional lithium storage mechanisms, a novel interfacial storage mode was predicted to occur in M/LiX nanocomposites (M stands for any electron conductor, e.g. metal, which does not alloy with Li). According to this mechanism, the individual charges (Li+, e-) are stored in the space charge layers, i.e., Li+ is accommodated at the Li2O side of the boundary, while the e- is restricted to the metal side. As neither of the composites could store Li by itself, this is called ‘job-sharing’ mechanism [1]. Recently, a thermodynamic model for interfacial storage was developed, which describes both semi-infinite and mesoscopic boundary conditions [2]. In this contribution, we present that the predicted power law for the Li-activity dependence of the capacity for a semi-infinite model can be reproduced, in both Li2O-Ru and LiF-Ni composites systems. Further exploitation of the interfacial storage mechanism may provide interesting information as to better compromise power and energy density for Li-ion batteries. Moreover, the correlations allow for a generalized storage picture of nanocrystals.
Reference:
[1] J. Jamnik and J. Maier, Phys. Chem. Chem. Phys., 5, 5215-5220 (2003).
[2] J. Maier, Angew. Chem. Int. Ed., 52(19), 4998-5026 (2013).
Investigation of Ether-Based Ionic Liquid Electrolytes for Lithium-O2 Batteries
Authors: Ferrari Stefania , Quartarone Eliana , Bini Marcella , Tomasi Corrado , Capsoni Doretta , Mustarelli Piercarlo 
Published: February 2020

The growing global energy demand of modern society is urging to find large-scale sources, which are more sustainable and environmentally friendly than the oil-based ones. At present, the capacity of the state-of-the-art lithium ion battery is limited and therefore, radically different approaches are required in order to fulfil the very demanding requests of energy storage. Rechargeable Li-O2/air batteries can potentially represent an interesting solution because they theoretically can store more energy than Li-ion batteries. At present numerous aspects of Li-O2 batteries deserve to be carefully investigated before becoming a commercial reality and among them the electrolyte is one of the main challenges.1 Ether based electrolytes have attracted a lot of interest because they combine several beneficial attributes; they are safe, low cost, stable up to 4.5V and they are of low volatility. Tetra(ethylene) glycol dimethyl ether (TEGDME) has been recently employed in Li-O2 batteries and with very good electrochemical performances.2 Hydrophobic ionic liquids (ILs) have been largely employed in case of the conventional Li-ion cells, however a few details on their behaviour in Li-O2batteries are still available.
In this work, we investigated the potential use as electrolytes of mixtures of TEGDME and ether functionalized ionic liquids (ILs). We show the results of the characterization of mixtures having different ratio TEGDME-ILs and containing LiCF3SO3 or LiTFSI salt by means of thermal analysis, conductivity and electrochemical stability measurements. In addition, their application in Li-O2 batteries has been assessed, investigating Li/TEGDME-IL/O2 cells by means of cycling voltammetry (CV) and galvanostatic charge-discharge tests. Oxygen reduction and evolution reactions (ORR and OER) have been studied in TEGDME-ILs mixtures to address the mechanism and reversibility of ORR and OER. Our results demonstrate that oxygen reduction and evolution take place in a reversible way and that ether-based electrolytes containing ionic liquids worthwhile of being further investigated for rechargeable Li-O2cells.
[1] D. Capsoni, M. Bini, S. Ferrari, E. Quartarone, P. Mustarelli J. Power Sources(2012) 220, 253.
[2] H.-G. Jung, J. Hassoun, J.-B. Park, Y.-K. Sun, B. Scrosati Nat. Chem. (2012) 4, 579
Construction of Direct-Growth in Situ Doped Polypyrrole/CNT Core Shell Composite on Carbon Cloth As a High Performance Flexible Supercapacitor
Authors: Yesi Yesi , Shown Indrajit , Ganguly Abhijit , Chen Li-Chyong , Chen Kuei-Hsien 
Published: February 2020

In the 21st century, the growing demand of the smart portable electronic gadgets, such as roll-up display, electric paper and wearable systems for smart electronics need to develop the flexible super capacitor with both high-power density and large energy density. Conducting polymers (CPs) are one of the most potential pseudo-capacitor materials for foundation of flexible-supercapacitors, motivating the existing energy storage devices towards the future advanced flexible electronic applications due to their high redox active specific capacitance and inherent elastic polymeric nature [1,2]. To the best of our knowledge, among CPs, polypyrrole (PPy) have shown better elasticity and conductivity than the polyaniline. However, a key weakness of the PPy based supercapacitor electrode is mechanical instability due to the considerable volume change during the repeated charge-discharge process. Consecutively binary composites of PPy with CNTs on flexible substrate have been explored on the traditional slurry process. A major limitation of the traditional slurry derived electrode consists in the sluggish rate of ion transport during the faradic reactions in electrode due to the high internal resistance of binders. To solve this problem in this work, polypyrrole/CNT core shell composite directly grown on flexible carbon cloth (CC). The CNTs were directly grown on the CC by microwave plasma-enhanced chemical vapor deposition in order to obtain a strong adhesion of CNT on CC, and then the in situ doped well uniform PPy/CNT core-shell composite was synthesized via oxidative electropolymerisation. The PPy/CNT/CC electrode fabricated by direct growth process with optimum thickness of PPy possesses the low interfacial resistance, and shows high gravimetric capacitance of 486.1 F/g with a mass loading around 6 mg/cm2 at a current density of 0.9 A/g. Furthermore, this PPy/CNT/CC electrode delivers remarkably a very high cycle stability (17% capacitance loss after 10000 cycles) and high flexibility. The detail core shell electrode fabrication process of PPy/CNT on flexible CC and their electrochemical pseudo-capacitance with stability performance will be discussed. These results clearly present a cost-effective and simple fabrication method of the PPy/CNT composite with enormous potential in flexible energy storage device applications.

References

[1] Y.Y. Horng, Y.C. Lu, Y.K. Hsu, C.C. Chen, L.C. Chen, K.H. Chen, Journal of Power Sources. , 2010, 195, 4418.
[2] I. Shown, A. Ganguly, L. C. Chen, K. H. Chen, Energy Science & Engineering, 2014, DOI: 10.1002/ese3.50.
A Novel Flow Battery Using Quinoxaline Derivatives As Redox Couple
Authors: Li Xue , Zhao Yang , Pan Jianxin , Xie Xiaofeng , Ramani Vijay K 
Published: February 2020

New and renewable energy resources are being developed to reduce the use of fossil fuels and decrease the greenhouse gas emission. Energy storage is now seen as the opportunity for improve energy efficiency and utilize discontinuous clear energy like the wind and solar power. Redox flow battery is now leading the way in electrochemical energy storage system for its low cost, flexibility and high efficiency. Flow batteries are almost metal based of which the most widely used is all vanadium redox flow battery. A breakthrough by using metal-free organic-inorganic redox couples as active materials. 9,10-anthraquinone-2,7-disulphonic acid (AQDS) undergoes extremely rapid and reversible two-electron two proton reduction on a glassy carbon electrode in sulphuric acid had made[1]. And a quinoxaline-derivatives as initial low-potential materials had employed and showed good columbic and energy efficiency[2].
Quinoxaline is a promising active material for flow batteries due to its low molecular weight, high solubility and ability to transfer two electrons per pyrazine ring. In this study, quinoxaline-derivatives were studied, and the reduction potentials including hydroxyquinoxaline and methylquinoxaline are calculated with DFT, while solvation free energies calculated by COSMO model. A better reversibility as well as rapid kinetics have been observed. The most of the derivatives are highly soluble in aqueous or non-aqueous solutions and the reduction potentials are relatively low (~-0.3V) indicate that can be combined with the Br2/Br- couple, which would show high energy efficiency. Electrochemical properties of quinoxaline-derivatives with various concentration, different additions, in different solvents will be tested which would involving Cyclic Voltammetry (CV), Electrochemical Impedance Spectroscopy (EIS), Rotating Disk Electrode and Rotating Ring-Disk Electrode (RDE and RRDE). The battery performance will be tested employing quinoxaline-derivatives and Br2/Br-as cathode and anode redox couples, respectively.

Key words:flow battery, redox couple, quinoxaline

Acknowledgment:This work was supported by the National High Technology R&D Program of China (2012AA053401)

References

[1] B. Huskinson, M.P. Marshak, et al. A metal-free organic––inorganic aqueous flow battery. [J] Nature. 2014, 505: 195-198.
[2] Fikile R. Brushett, John T. Vaughey, and Andrew N. Jansen. An All-Organic Non-aqueous Lithium-Ion Redox Flow Battery. [J] Adv. Energy Mater. 2012, 2, 1390–1396.
Operando X-Ray Diffraction As a Tool to Monitor Compositional Gradients in Battery Electrodes
Authors: May Brian M , Kim Cheon Jung , Yu Young-Sang , Cabana Jordi 
Published: February 2020

Batteries are a crucial technology for a society to move away from fossil fuels. The amount of energy a battery can store is proportional to the amount of charge transferred by the cathode and anode [1]. To maximize this energy, electrode thickness is maximized. These electrodes are made of a porous active material which allows for lithium transport in and out of the materials. Inhomogeneities will be observed due to the non-uniformity of the pores, as well as the conductive additive within the cell. Therefore, the rate of lithium insertion/removal is dependent on the location within the electrode. As the electrode thickens, the inhomogeneities will increase as a function of the distance from the anode, resulting in gradients normal to the electrode. The development of these gradients is also associated with transport within the active material.
X-ray diffraction (XRD) is a powerful technique that can provide structural information on the unit cell [2]. Performing operando experiments can reveal information on the dynamic composition of the electrode. The materials of interest are various compositions of LiMO2 (M=Ni, Mn, Co, Al), crystallizing in a layered α-NaFeO2-type structure. These materials have high theoretical charge capacities, yet can only stably cycle at a fraction of them during operation [3]. During each charge cycle, the material transforms following a second-order phase transition involving continuous miscibility between end states, which is easily followed by diffraction. In the presence of chemical gradients that take place during the transformation, the XRD peaks would progressively broaden. These gradients will vanish when the circuit is open. We validated this hypothesis with LiNi0.33Co0.33Mn0.33O2 (NCM111) electrodes. Peaks broadened during the reaction and faded during relaxation, especially at high rates. Figure 1 demonstrates this phenomenon when charging to 4.3V at a 1C rate (60 minutes for full charge). We leveraged the high penetration enabled by the 115 keV beam in beamline 11-ID-C at Advanced Photon Source to do the measurements in coin cells without thin windows, to ensure constant isostatic pressure and avoid undesired sources of chemical gradients. In this presentation, we will summarize the results obtained in a variety of experimental conditions, such as rate, voltage window and electrode porosity. The observations help explain how gradients are formed within positive electrodes based on layered oxides and can provide information on why the theoretical capacity has yet to be achieved in application.
References
1. A. Van der Ven, J. Bhattacharya, A. A. Belak, Accounts of Chemical Research 46, 1216-1225 (2012)
2. He, B. Two-dimensional X-ray Diffraction. 2009.
3. Goodenough, J. B.; Kim, Y. Chem. Mater. 2010, 22, 587-603.

Figure 1
Studies on Kinetics and Mechanism for Rechargeable-Iron Electrodes Using in Situ x-Ray Diffraction Technique in Conjunction with Electrochemistry
Authors: Ravikumar Musuwathi Krishnamoorthy , Sundar Rajan Aravamudan , Shukla Ashok Kumar 
Published: February 2020

Iron is the fourth most abundant element on the earth’s crust. It is cost effective, has large theoretical specific capacity and is non-toxic. Iron-based accumulators are both mechanically and electrically rugged. Besides, iron electrodes are also environmentally benign unlike other battery electrode materials, such as cadmium and lead.1 Open-circuit potential of a charged alkaline-iron electrode is always negative to hydrogen evolution reaction. Consequently, iron is thermodynamically unstable and suffers corrosion through concomitant evolution of hydrogen. Hydrogen evolution also occurs while charging alkaline iron electrodes bringing about a decrease in their charge acceptance. Several sulfide additives, like FeS, PbS and Bi2S3, have been used to increase hydrogen over-potential to mitigate this problem. Recently, we reported a carbon-grafted alkaline iron electrode for iron-based accumulators with specific capacity values in excess of 400 mAh g-1 with faradaic efficiency of about 80%.2 In this study, we report in situ x-ray diffraction investigations on charge and discharge products of carbon-grafted iron electrodes with and without Bi2S3 additive to throw light on a feasible charge and discharge mechanism in these electrodes. When iron electrodes with Bi2S3 additives are subjected to formation cycle Fe3O4 is reduced to metallic α-Fe. Interestingly, carbon-grafted iron electrodes with Bi2S3 exhibit complete conversion of Fe3O4 to α-Fe at the end of formation cycles and, consequently, it is surmised that carbon grafting into the iron active material promotes utilization of active material.
References:

S.R. Narayanan, G.K. Surya Prakash, A. Manohar, Bo. Yang, S. Malkhandi and Andrew Kindler, Solid State Ionics, 216, 105 (2012).

A. Sundar Rajan, S. Sampath and A.K. Shukla, Energy Environ. Sci.,
7, 1110 (2014).
Chemiacl Potential and Degradation of Solid Electrolyte for SOFCs
Authors: Lim Hyung-Tae , Jung Myung Geun , Park Mi-Young 
Published: February 2020

The stability of a solid oxide fuel cell (SOFC) stack is strongly dependent on the magnitude and profile of the internal chemical potential of the solid electrolyte. If the internal partial pressure is too high, the electrolyte can be delaminated from the electrodes. The formation of high internal pressure is attributed to a negative cell voltage, and this phenomenon can occur in a bad cell (with higher resistance) in a stack. This fact implies that the internal chemical potential plays an important role in determining the lifetime of a stack. In the present work, we fabricate two kinds of electrolyte, oxygen ion conductor (YSZ) and proton conductor (BCY), for solid oxide fuel cells and conduct degradation tests under a negative voltage condition, as a function of electrolyte structure and composition. Results indicate that the addition of electronic conduction in the electrolyte with bi-layer structure can effectively enhance the cell stability, especially under severe operating conditions.
Electrochemical Study on the Impact of Metallization on Si Particles for Li-Ion Negative Electrode
Authors: Spreafico Marco Alberto , Cojocaru Paula , Oriani Andrea Vittorio , Triulzi Francesco , Magagnin Luca , Apostolo Marco , Biso Maurizio 
Published: February 2020

Li-ion batteries are widely used in a large number of devices that are used in everyday life, from Smart Devices to Hybrd Electric Vehicles (HEVs). The research is prompted towards the development of innovative materials that can further enhance the performances of batteries1,2.
Research on anodic materials is of crucial importance to meet the requirements for cited applications in terms of power and energy density. On this side, Silicon is considered to be the most promising material in terms of deliverable theoretical specific capacity, 4200 mAh/g. However, cycling performances of Silicon are jeopardized by the structural instability suffered from the material upon charge/discharge cycling. To address this issue, different solutions have been tested3
,
4. The approach developed in this work is to apply a metallic coating to the Si particles by electrochemical techniques, i.e. electroless deposition and galvanic displacement.
In this work, a study of the electrochemical impact of the coating on the behavior of the electrode will be done in two steps. First, an assessment of the growth mechanism of metallic coating on Si particles will be carried out by means of SEM analysis. Then, the electrochemical characterization of electrodes containing metallized particles will be carried out by means of electrochemical impedance spectroscopy, SEM analysis and coin cell cycling.
References:
1. J. B. Goodenough and Y. Kim, Chem. Mater., 22, 587–603 (2010)
2. Y. Sun et al., Nat. Mater., 11, 942–947 (2012)
3. C. K. Chan et al., Nat. Nanotechnol., 3, 31–5 (2008)
4. B. A. Boukamp, J. Electrochem.
Soc., 128, 725 (1981)
Ionic Permeability within Thermally-Activated Batteries
Authors: Humplik Thomas , Stirrup Emily K. , Wesolowski Dan Edward , Allen Ashley Nicole , Grant Richard P. , McKenzie Bonnie B. , Roberts Christine C. , Roberts Scott A. , Mondy Lisa Anne , Grillet Anne M. 
Published: February 2020

Thermally-activated (or molten salt) batteries utilize high melting temperature (> 300 ºC) salts as the electrolyte. Since the electrolyte is solid at room temperature, an advantage of these types of batteries is that there is no self-discharge prior to activation, which significantly increases the shelf life compared to conventional electrochemical batteries. To activate the battery, a heat source (usually an internal pyrotechnic) is required to melt the electrolyte and enable current flow. During the melting/activation process, the separator in each cell thins until the oxide binder supports the cell compaction force. An open question is what becomes of the melted electrolyte within the separator and electrodes during activation. The transport and infiltration of the electrolyte into the electrodes can reduce the internal impedance of the cell; however, excess electrolyte could cause shortage and failure of the battery. Therefore, an improved fundamental understanding of the governing transport properties of the electrolyte is needed to better predict the performance of thermal batteries during activation.
In this work, we performed a series of fundamental studies to probe the ionic mobility and conductivity of the electrolyte. First, by utilizing a series of single cells frozen at various activated times, we performed electron probe microanalysis (EPMA) on the cell cross-sections to quantify the transport of bromine tracers. Through the use of image analysis techniques, we mapped out of the concentration of bromine throughout each cell and elucidated the complex process of electrolyte diffusion and flow. Next, using a custom-built pressure vessel cell, we quantified the permeability of the electrolyte through the oxide binder during and after activation. Furthermore, we investigated the effects of compaction pressure on both the permeability and internal impedance of the separator. Collectively, these experimental studies provide quantitative transport information about the electrolyte, which can be used to inform predictive models for battery activation and improve the understanding of the impact of separator compaction on electrolyte transport properties.
Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-AC04-94AL85000.