bluuebunny/crossref_metadata_2025 huggingface dataset:
Li-Rich Cathode Material Enhancement through Atomic Surface Reduction
Authors: Evenstein Eliran , Sharma Rosy , Haber Shira , Leung Kevin , Leskes Michal , Noked Malachi
Published: February 2020

Lithium Ion batteries (LIB) have revolutionized the portable electronics industry for over two decades, with high energy density, cycle capability and safety. In recent years the LIBs are the lead candidate to fuel the power demands of electric vehicles (EVs). However, current generation cathode materials fall short in terms of energy density for fulfilling the demands of future applications (energy storage, EVs, etc.).

Li-Rich materials are the main contenders to become the next generation rechargeable li ion cathode material. Li-Rich materials are a family of layered materials which consist of Li, Mn, Co and Ni Oxides. One promising compound of Li-rich material contains two phases: X(Li2MnO3) - (1-x)(LiMnaNibCocO2) where (a+b+c=1) . These materials exhibit high capacity (~250mAhrg-1 vs. ~170mAhrg-1 of current Generation cathodes), good stability and are safe for use. However, upon cycling, the Li-Rich cathodes suffer from voltage decay, which is currently attributed to be evolution of O2 which causes a Redox process on the surface.

We propose a new method for enhancement of the Li-rich cathode stability by controlled surface modification. The modification aims to control the oxygen evolution during cycling and thus control the voltage decay. This method shows improvement in the voltage stability during cycling and capacity retention.

Figure 1
In Situ NMR Analysis of Lithium Metal Surface Deposits from Electrolytes with Varying Salt Concentrations
Authors: Küpers Verena , Kolek Martin , Bieker Peter , Winter Martin , Brunklaus Gunther
Published: February 2020

Lithium metal constitutes a promising anode material, based on its high theoretical specific capacity (3 860 mAh g−1), and low electrochemical potential (−3.04 V vs. SHE). Non-homogeneous lithium deposition, however, may lead to the formation of reactive high surface area lithium (HSAL) upon cycling, eventually yielding losses of active material, safety risks, and insufficient cycling efficiency. HSAL with e.g. needle-like structure does not only cause higher capacity losses based on side reactions and solid electrolyte interface (SEI) formation, but also could result in internal short circuits by penetration of separator layers. In contrast, low surface area lithium (LSAL) such as nodule-like deposits[1] may reduce unwanted side reactions as well as safety risks. The actual microstructure of lithium deposits is governed by extrinsic factors including cell pressure, temperature, current densities, as well as surface properties of lithium metal electrodes but also the explicit choice of electrolyte constituents, and is therefore crucial for the overall cell performance.[2] In this work, highly concentrated electrolytes are exploited to achieve improved cycling stability and reduced HSAL formation, where the formation of a highly robust SEI, more uniform lithium deposits, fewer side reactions on the anode surface, as well as higher viscosity of the electrolytes were identified as key factors.[1, 3]

Electrochemical in situ investigations, scanning electron microscopy (SEM) [4] and in situ
7Li nuclear magnetic resonance (NMR) spectroscopy [5, 6] are applied to in detail elucidate lithium deposition phenomena in symmetrical Li/Li cells. In addition to SEM data, in situ
7Li NMR constitutes an alternative, highly viable spectroscopic method that affords (semi-) quantitative and qualitative monitoring of lithium microstructure growth upon cycling, thereby unraveling critical processes during electrodeposition while delivering counterstrategies for unrestrained HSAL growth and options for achieving significantly improved electrochemical performance and life time of the considered cells.

[1] J. Qian, et al., Nature Communications, 6 (2015) 6362.

[2] X.-B. Cheng, et al., Chemical Reviews, 117 (2017) 10403-10473.

[3] L. Suo, et al., Nature Communications, 4 (2013) 1481.

[4] G. Bieker, et al., Physical Chemistry Chemical Physics, 17 (2015) 8670-8679.

[5] H.J. Chang, et al., The Journal of Physical Chemistry C, 119 (2015) 16443-16451.

[6] R. Bhattacharyya, et al., Nature Materials, 9 (2010) 504-510.
Trash to Energy: From Sugarcane Bagasse to High-Performance Anodes for Sodium-Ion Batteries
Authors: Li Chi , Patra Jagabandhu , Rath Purna Chandra , Chang Jeng-Kuei
Published: February 2020

Sodium-ion batteries (NIBs) are considered as next-generation energy storage devices to substitute lithium-ion batteries in large-scale energy storage systems for smart grids and electric vehicles. Pursuing low-cost, resource-abundant, and high-performance anodes are decisive to the future growth and expansion of NIBs. Recently, several suitable cathode materials for NIBs have been successfully developed and investigated. However, the major hurdle is to obtain appropriate anode materials with reversible electrochemistry and fast kinetics for NIBs. Herein, we have successfully developed a new hard carbon (HC) anode derived from abundant sugarcane bagasse (SB) as the biomass precursor. We synthesized SB hard carbon (SB-HC) under various carbonization temperatures. SB has a unique balance of lignin, cellulose, and hemicellulose, which avoids full graphitization of the pyrolyzed carbon but guarantees an adequately ordered carbon structure for Na-ion transport. When compared to HC derived from waste apple biomass, which is rich in pectin and has less cellulose compared to SB, SB‐HC is less defective and has lower oxygen content. As a result, SB‐HC has a higher first‐cycle charge/discharge coulombic efficiency and enhanced cycling stability. In addition, SB‐HC has a distinctive flake‐like morphology, which can reduce Na+ diffusion length, resulting in outstanding high‐rate charge-discharge performance. The effects of pyrolysis temperature on electrochemical properties of both HC anodes are comprehensively studied.
Enhanced Supercapacitor Performance By Tuning the Wettability of Vapor Grown Carbon Nanofibers Using Oxygen Plasma Treatment
Authors: Avasthi Piyush , Arya Nitika , Balakrishnan Viswanath
Published: February 2020

Carbon based materials have been explored widely for supercapacitor applications in commercial perspective. Despite that their poor performance in terms of volumetric and gravimetric capacitance seems bottleneck in high performance supercapacitor device applications. The major reason for the same is their poor wettability. Generally, carbon based materials are found to be hydrophobic which limits their electrode – electrolyte interfacial interaction and hence, suppresses the charge storage performance.

In this work, we report vapor grown carbon nano fibers (CNF) at large scale using chemical vapor deposition adopting simple catalytic approach. CVD grown CNF showed crystalline 1 D morphology confirmed by detailed electron microscopy. As grown CNF shows hydrophobic nature. Supercapacitor measurements revealed 14.6 mF/cm2 aerial capacitance. In order to improve electrode - electrolyte interfacial interaction, the wettability factor has to be improved and hence O2 plasma treatment has been adopted to convert hydrophobic CNF into hydrophilic. Time dependent contact angle measurements revealed the absence of ageing effect due to changes in microstructure after plasma treatment which was confirmed by electron microscopic investigations. Further, comparative electrochemical measurements proved remarkable enhancement in supercapacitor performance of plasma treated CNF in terms of aerial capacitance (162.5 mF/cm2) compared to as grown CNF. The change in wettability led to superior supercapacitor performance along with high Coulombic efficiency. Taking this work to one step further CNF were uniformly encapsulated with MoO3 in 1 D core – shell fashion where CNF acts as core and MoO3 acts as shell in the subsequent CVD process. This approach provides a path in developing low cost - high energy density supercapacitor using simple methods.
A Redox-Flow-Battery Based on Aqueous Polyoxometalate Electrolytes
Authors: Pfanschilling Felix Leon , Friedl Jochen , Holland-Cunz Matthäa Verena , Cording Faye , Schricker Barbara , Fleck Robert , Wolfschmidt Holger , Stimming Ulrich
Published: February 2020

In order to utilise intermittent renewable energy sources like wind and solar power more efficiently, flexible and inexpensive electricity storage capabilities are required. One particularly well-suited option for this task are Redox-Flow-Batteries (RFBs). RFBs are the only type of battery where power and capacity can be scaled independently, thus providing high flexibility and versatile applications.

However, the prevailing technology, the all vanadium system, comprises low energy and low power densities. We investigate two polyoxometalates (POMs), [SiW12O40]4- and [PV14O42]9-, as nano-sized electron shuttles.1 We show that these POMs exhibit fast redox kinetics (electron transfer constant k
0 ≈ 10-2 cm s-1 for [SiW12O40]4-), thereby enabling high power densities. Furthermore, we could show that these POMs exhibit some more favourable properties for their use in a battery, like high solubility, multiple redox-centres per molecule and a high (electro)chemical stability, which lead to high energy densities and long cycle lifetimes. Water as a solvent provides inherent safety to the system, as no flammable electrodes or electrolytes are used.

In collaboration with Siemens AG, we were also able to scale up the presented system from a 25 cm2 lab cell to a cell with 1400 cm2.2 Cycling over a period of nearly three months provided some very promising results, including a coulombic efficiency of nearly 100%. Post-cycling analysis of the electrolytes indicated no sign of degradation and the observed capacity loss of 0.011% per cycle could be attributed to air oxidation. The energy efficiency dropped from 86.1% to 85.1% over the course of 1400 cycles, again showing a highly stable performance.

References

1 J. Friedl,M. V. Holland-Cunz, F. Cording, F. L. Pfanschilling, C. Wills, W. McFarlane, B. Schricker, R. Fleck, H. Wolfschmidt, U. Stimming, Energy Environ.
Sci., 2018, 11 (10), 3010–3018. https://doi.org/10.1039/C8EE00422F

2 J. Friedl, M. V. Holland-Cunz, F. L. Pfanschilling, R. Fleck, B. Schricker, H. Wolfschmidt, U. Stimming, submitted.
Spherical Si-Nb2O5-C Composite As Anode Materials for Li Secondary Batteries
Authors: Park Dahye , Kim Jae-Hun
Published: February 2020

In recent years, Li-ion batteries have attracted much attention as the demand for electronics and electric vehicles has increased. Currently, graphite is used as anode materials for Li-ion batteries because of its good cycle performance and reasonable cost. However, graphite has a relatively low specific capacity of 372 mAhg-1 due to its lithium storage mechanism. The low theoretical capacity of graphite does not meet the consumer's need for batteries with high capacity. Therefore, development of new anode materials with high capacity are strongly required. Among diverse Li storage materials that can replace graphite, Li-alloy based materials including group IV elements have been widely researched due to their high theoretical capacity. In particular, silicon has attracted great attention as anode materials for Li-ion batteries due to its high capacity and natural abundance. However, silicon anodes generally suffer from volume expansion during the Li insertion and extraction process, which results in poor cycle performance. To overcome the problem, strategies to suppress the volume expansion of silicon should be suggested.

In this work, we synthesized carbon-coated niobium oxide-silicon composites. Niobium oxide (Nb2O5) has various crystalline polymorphs such as pseudo-hexagonal (TT-Nb2O5), orthorhombic (T-Nb2O5), tetragonal (M-Nb2O5) and monoclinic (H-Nb2O5). These various crystalline polymorphs of Nb2O5 can be prepared by varying the heat treatment temperature, of which orthorhombic structure is favorable for fast Li ions storage. T-Nb2O5 exhibits excellent rate performance during cycling due to its Li insertion/desertion mechanism. However, T-Nb2O5 has a relatively low capacity and thus, silicon and T-Nb2O5 were combined to obtain a high capacity and stable cycle performance. In addition, to increase the electrical conductivity of both silicon and T-Nb2O5, carbon incorporation was employed. First, niobium oxide-silicon composite with micrometer-sized spherical structure was prepared by a solvothermal method. In the microsphere, nanosized Si and Nb2O5 were uniformly distributed. Then, the heat treatment was done with naphthalene at 800℃ to perform both phase transformation to T-Nb2O5 for fast Li transport and carbon coating for cycle performance and enhanced electrical conductivity. As a result, a nanometer-thick carbon layer was coated on the surface. Electrochemical test results exhibited that the synthesized electrode materials showed a high reversible capacity, excellent cycle life, and good rate performance as anode materials for Li rechargeable batteries.
ZnO-Carbon Nanostructure Derived from Metal-Organic Framework As Stable Lithium Metal Anodes
Authors: Kim Kyungbae , Kim Jae-Hun
Published: February 2020

Recently, research interest in next-generation rechargeable batteries is focused on lithium (Li) metal batteries due to its high specific capacity (3860 mA h g–1) and lowest redox potential (–3.04 V vs standard hydrogen electrode). However, they have two serious drawbacks, which are unstable Li deposition/dissolution during cycling and low cycle efficiency, to use in practical Li storage applications. These problems are strongly related to dendritic Li growth mechanism, and many strategies have been proposed to suppress the Li dendritic growth. One of the favorable method is to control the stability of surfaces by designing stable artificial interfaces for Li nucleation and growth. In this study, we adopted a simple sol-gel method to synthesize the zeolitic imidaloate framework-8 (ZIF-8). ZIF-derived nitrogen-doped ZnO-carbon scaffold was obtained by pyrolysis of ZIF to construct the novel structure for Li deposition. The porous electrode can reduce intensive local current density for Li metal growth. The three-dimensionally interconnected porous surface confines the metallic Li within the nanostructure leading to filling the ZnO-carbon scaffold as well as covering the electrode surface. We demonstrate a design of ZIF-derived lithiophilic ZnO-carbon nanostructure to use as a Li metal anode. The obtained porous electrode provides fast electron transfer and Li ion diffusion as well as reduces the local current density. As a result, the structure leads to flat voltage profiles and stable cycle life over 100 cycles at a current density of 2 mA cm–2.
Mobility of Intermediates in Highly Channeled Reaction Cascades
Authors: Xie Yan , Calabrese Barton Scott
Published: February 2020

Novel and energy systems and synthetic processes can benefit from multistep chemical cascades, which allow combination of multiple reaction in a single overall process. Such cascades are ubiquitous in nature, and have been applied to of biosensors and biofuel cell designs as well. But, the efficiency of cascade reactions is significantly limited by the transport of intermediates. Intermediate channeling phenomenon is found to be one of the solutions to this problem in nature, and can include confinement, electrostatic interactions, and other mechanisms. Here we describe the quantitative tools we have developed to describe these channelling systems quantitatively, and to interrogate them experimentally. We specifically apply analysis techniques for infrequent events such as occur with tightly bonded intermediates to probe the tradeoff between retention of intermediates near or within catalytic complexes, and the reduction of mobility such retention entails. We show that because of the very short time scales of transport as compared to reaction, strong retention of intermediates is advantageous even if such retention dramatically reduces intermediate mobility.
Online Electrochemical Mass Spectrometer (OEMS): A Smart Pathologist for Batteries
Authors: Sharma Rosy
Published: February 2020

Online Electrochemical Mass spectrometry (OEMS) is a very important tool for in-operando detection of evolved gases as a function of applied potential on the real-time scale. In-Operando gaseous evolution studies are very important to know the battery health and the reasons behind its failure. We herein, show with examples that OEMS analysis can give a deep insight into the reactions happening inside the battery. It can be used to trace onset potential for parasitic reactions like electrolyte degradation, electrode corrosion and thus can help in optimizing the working conditions and interfacial protection strategies. Using the OEMS studies, the reaction products like HF, POF3, CO2, O2 etc. can be analyzed even in trace quantities.
Impact of a Maturation Procedure on the Morphological Dynamics of Si-Based Anodes for Li-Ion Batteries Characterized By I
n-Situ Synchrotron X-Ray Tomography
Authors: Vanpeene Victor , Villanova Julie , King Andrew , Lestriez Bernard , Maire Eric , Roué Lionel
Published: February 2020

Thanks to its theoretical capacity ten times higher than graphite (3579 mAh g-1 for Li15Si4
versus 372 mAh g-1 for LiC6), substituting graphite by silicon as anode material in lithium-ion batteries is an attractive way to increase their energy density. However, the huge volume expansion/contraction of silicon (up to ~300%) during its lithiation/delithiation causes major morphological changes of the electrode, which severely degrade its cyclability. In this communication, the dynamics of their expansion and contraction, of their cracking in the bulk and of their debonding at the interface with the current collector are characterized by in situ synchrotron X-ray computed tomography. Two electrodes made with micrometric silicon material are compared: one fabricated according to a standard process and the other one prepared with a maturation step, which consists in storing the electrode in a humid atmosphere for a few days before drying and cell assembly [1]. Various morphological parameters are quantified and followed during the first lithiation/delithiation of the electrode, namely (i) the dimensional change of the electrode, (ii) the volume fraction, size and connectivity of the segmented solid, gas and electrolyte phases, (iii) the volume fraction, size and connectivity of the produced macrocracks, (iv) the surface area of the produced delaminated zones from the current collector and (v) the variation of the Si inter-particle distances. All morphological degradations are significantly restrained for the matured electrode, confirming the great efficiency of this maturation step to produce a more ductile and resilient electrode architecture, which is at the origin of the major improvement in their cyclability.

[1] C.R. Hernandez, A. Etiemble, T. Douillard, D. Mazouzi, Z. Karkar, E. Maire, D. Guyomard, B. Lestriez, L. Roué, Adv. Energy Mat.
2017, 8, 1701787.

Figure 1
In Situ Chemo-Mechanical Responses of Lithium Iron Phosphate Electrodes during Electrochemical Cycling
Authors: Çapraz Ömer Özgür , Bassett Kimberly , Gewirth Andrew A. , White Scott R. , Sottos Nancy R.
Published: February 2020

Rechargeable Li-ion batteries (LIBs) have been successfully commercialized for portable electronics in the last two decades. Although there has been a great interest to use LIBs in more demanding applications such as electric vehicles, adoption of LIBs has been hindered by capacity loss and poor performance. The current stage of the cathode performance is a limiting factor for the development of higher performance LIBs. Lithium intercalation induces considerable volumetric changes with associated stress generation in the electrode. Even small strain can cause particle fractures in brittle cathode materials. The formation of a fracture particles leads to the capacity fade and limits the lifetime of batteries. To investigate chemo-mechanical response of the cathodes, we previously calculated electrochemical stiffness changes cathodes by coordinating in situ stress and strain measurements1. The electrochemical stiffness response of lithium manganese oxide revealed that the underlying mechanisms governing stress and strain are intrinsically different. In this study, our objective is to evaluate chemo-mechanical responses of lithium iron phosphate (LFP) cathode.

In situ stress measurements were carried out with the beam curvature method whereas digital image correlation (DIC) is utilized to measure in situ strain generation. Electrodes are constrained on the cantilever for stress measurement, whereas free-standing electrodes were fabricated for strain measurements. LFP electrodes were fabricated with a composition of 8:1:1 weight ratio of LFP, carboxymethyl cellulose binder and carbon black. Electrodes are cycled with cyclic voltammetry technique at different scan rates (between 10 and 250μV/s) in various electrolytes. Stress and strain derivatives are calculated with respect to applied potential. Derivatives present crucial information to probe potential-dependent surface stress evolutions and structural changes in the electrode. As expected, strain derivatives are well-correlated with the changes in the crystal structure during delithiation and lithiation. Interestingly, stress derivatives reveal that electrolyte solution has a role on the evolution of surface stress. Changes in stress and strain during electrochemical cycling reveal underlying mechanisms governing chemo-mechanical responses in the LFP electrode.

References

1- Ö. Ö. Çapraz, K. L. Bassett, A. A. Gewirth, and N. R. Sottos, Adv. Energy Mater., 1601778–7 (2017).

Acknowledgement

This work was supported as part of the Center for Electrochemical Energy Science (CEES), an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences.”
Effect of Ionomer Binder on Performance and Durability of Catalyst Layers
Authors: Park Jong-Hyeok , Lim Seohee , Park Jin-Soo
Published: February 2020

Energy conversion devices often needs movement of ions between two electrodes, i.e., anode and cathode. Ions reached in front of electrodes should be transported within electrodes to participate in anodic and cathodic reactions. Pathway for ions is normally in an aqueous phase. Regardless, the introduction of any aqueous phase in energy conversion devices causes many problems during fabrication, operation, maintenance, and so on. Thus, much efforts have been devoted to develop quasi-solid electrolytes such as gel polymer, ion exchangeable polymers, impregnation of ions in porous matrix and so on. Among the candidates, ion exchangeable polymers are quite often chosen as ion conducting media for energy conversion devices. The technique to introduce ion exchangeable polymers within electrodes for oxidation and reduction reactions is to solidify catalyst inks consisting of electrocatalyst, dispersion of ion exchangeable polymers, controlling solvents and additives by evaporation of all solvents in catalyst inks. Ion exchangeable polymers could be dispersed in various solvents. It causes different shapes of ion exchangeable polymers in solvents, for instance, cylindrical rods, a less-defined large particles, coils and so on. Such different types of ion exchangeable polymers form distinguished structure catalyst layers. In this study, the effect of solvents dispersing ion exchangeable polymers on the performance and durability of catalyst layers was investigated. Electrochemical characterization such as I-V polarization, cyclic voltammetry, impedance and so on and microscopic characterization such as SEM and TEM were carried out to evaluate the performance and durability of catalyst layers.

Acknowledgement

This work was supported by the New and Renewable Energy of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) granted financial resource from the Ministry of Trade, Industry & Energy, Republic of Korea (No. 20173010032100).
Effects of Various Graphite Cathodes on Self-Discharge Behavior of Rechargeable Aluminum Batteries
Authors: Li Chi , Rath Purna Chandra , Chang Jeng-Kuei
Published: February 2020

Renewable energy technologies, such as wind power and solar energy, have become great importance in modern society [1]. Unfortunately, the intermittent nature of these energies leads to a huge barrier in energy generation and stabilization in electricity supply [2]. The rechargeable batteries received a lot of attention due to high energy density and satisfactory cycle life. Rechargeable aluminum batteries (RABs) gain a great amount of research interest in recent times due to the low cost of aluminum compared to that of lithium. Aluminum, being the most abundant metal in the earth crust, has three-electron transfer characteristic, high volumetric capacity, and great safety, which make RABs suitable for large-scale energy storage [3].

However, problems like low discharge voltage, high corrosion of electrolyte, serious self-discharge impede the growth and development of RABs. Jiao’s group demonstrated self-discharge phenomena for Ah-level RABs, where self-discharge rate was about 6%/day [4]. Their research only presented the self-discharge phenomena, but not studied the factors affecting self-discharge behavior. Self-discharge is an important issue for practical applications. The self-discharge rate of RABs is much higher than that of commercial lithium-ion batteries, whose self-discharge rate is approximately 5%/month. It is thus necessary to investigate the factors affecting self-discharge properties of RABs.

In this work, effects of various types of graphite cathodes on charge-discharge properties and self-discharge behavior in ionic liquid electrolyte are studied. The results demonstrate that the changes in d-spacing and morphology of the graphite are crucial. The phase transformation of the graphite cathode during charging/discharging and self-discharge is examined using in-situ X-ray diffraction (performed at National Synchrotron Radiation Research Centre, Taiwan). The reaction mechanism is discussed in details.

References

[1] B. Huskinson,M. P. Marshak, C. Suh, S. Er, M. R. Gerhardt, C. J. Galvin, X. Chen, A. Aspuru-Guzik, R. G. Gordon, M. J. Aziz, Nature, 505 (2014) 195.

[2] Z. Yang, J. Zhang, M. C. Kintner-Meyer, X. Lu, D. Choi, J. P. Lemmon, J. Liu, Chem. Rev., 111 (2011) 3577.

[3] G. A. Elia, K. Marquardt, K. Hoeppner, S. Fantini, R. Lin, E. Knipping, W. Peters, J. Drillet, S. Passerini, R. Hahn, Adv. Mater., 28 (2016) 7564.

[4] S. Jiao, H. Lei, J. Tu, J. Zhu, J. Wang, X. Mao, Carbon, 109 (2016) 276.
One-Step Electrosynthesis of Polypyrrole/PbOx Composite in Acetonitrile As Supercapacitor Electrode Material
Authors: Karaca Erhan , Gokcen Dincer , Özçiçek Pekmez Nuran , Pekmez Kadir
Published: February 2020

This study explores the single step electrochemical synthesis of polypyrrole/PbOx composite on the Pb-intercalated (intc.) graphite electrode in acetonitrile medium, including Py, TBABF4, HBF4, H2O, Pb(BF4)2, TX100 and carboxymethyl cellulose. The coatings on Pb-intc. graphite surface are analyzed by SEM-EDX, BET, TEM, XPS, and XRD techniques. The effects of the additives on the capacitive properties are investigated electrochemically in an H2SO4/water medium. PbOx and carboxymethyl cellulose enhance the specific capacitance and the cyclic stability. Although the amount of PbOx in the composite is low (1.2% atomic percentage of Pb), it contributes significantly to the specific capacitance due to the homogenous distribution of PbOx in nanostructures. The amount of specific capacitance of the composite film (4.0 mg cm−2 loading) on the Pb-intc. pencil graphite is calculated as 377 F.g−1 at 2.0 A.g-1 in 100 mM H2SO4
by subtracting that of bare graphite. The two electrode cells (asymmetric and symmetric) are constructed using Teflon Swagelok in polyvinyl alcohol/H2SO4 gel electrolyte. In the symmetric supercapacitor configuration, the composite coating (10 mg cm-2 loading) on Pb-intc. graphite paper electrode has 0.29 kW kg-1 and 22 Wh.kg-1 at 0.5 A g-1. The results also indicate a good cycle performance (94% after 5000 cycles) in the potential range of 0.8 V.
Effect of Electrolyte Salt Concentration on the Electrochemical Performance of K-Ion Batteries Using Diglyme-Based Electrolytes
Authors: Katorova Natalia S. , Rupasov Dmitry P. , Fedotov Stanislav S. , Luchinin Nikita D. , Abakumov Artem M. , Stevenson Keith J.
Published: February 2020

The increased amount of studies has been performed in recent years to attain the capacity and energy characteristics of potassium-ion batteries being competitive to the lithium-ion one. However, the electrolyte choice has been observed to be the bottleneck for the stable electrochemical performance of the potassium-ion batteries in terms of the formed solid electrolyte interface (SEI) and cathode electrolyte interface (CEI). In the presented research the drawbacks of the conventional carbonate-based electrolyte usage are shown. Moreover, the advantages provided by the diethylene glycol dimethyl ether (so-called diglyme) as a solvent is considered. The effect of salt concentration in diglyme-based electrolytes on cycling performance of promising KVOPO4 and K1.69Mn[Fe(CN)6]0.85×0.4H2O cathodes and hard carbon anode for next-generation potassium-ion (K-ion) batteries is investigated. A decrease in free solvent molecular number with increasing electrolyte concentration is found, which results in a better aluminum current collector stability, formation of thinner solid electrolyte interphase (SEI) passivation layers and further inhibition of solvent degradation redox processes occurring at the electrode surface upon cycling. The KVOPO4 and K1.69Mn[Fe(CN)6]0.85×0.4H2O cathodes exhibit an enhanced specific discharge capacity (54 and 105 mA·h·g-1 respectively) in K-ion cells at the highest electrolyte concentrations (2 M and 2.5 M KPF6 in diglyme, respectively) at a C/10 rate. However, the behavior of the hard carbon anode is noticeably affected by the salt concentration over the first few cycles, a phenomenon tentatively attributed to the SEI layer formation and the presence of irreversible intercalation sites for K+ ions in the hard carbon framework. Finally, electrochemical tests of K-ion full cells consisting of the K1.69Mn[Fe(CN)6]0.85×0.4H2O cathode, hard carbon anode and ether-based electrolyte show capacity retention of 86% over 300 cycles at a 0.6C rate (figure 1). The results clearly show the impact of solvent-salt choice on the K-ion battery performance. We believe the achieved results prove the feasibility of full K-ion battery implementation, however, the future study is required.

Figure 1. Comparison of galvanostatic measurements of K full cells comprised of K1.69Mn[Fe(CN)6]0.85×0.4H2O cathode and hard carbon anode with carbonate-based and ether-based electrolytes. a) Variation in the specific discharge capacity with cycle number, and b) Dependence of the Coulombic efficiency on the cycle number.

Figure 1
HC-Based Anode Materials: Synthesis, Study and Evaluation of the Charge Storage Mechanism
Authors: Bobyleva Zoia V. , Drozhzhin Oleg A. , Antipov Evgeny V.
Published: February 2020

Hard carbon is a class of carbon materials widely used in sodium-ion batteries which are characterized by sp2 hybridized carbon atoms forming highly irregular structure consisting of randomly oriented graphene layers[1]. These materials have a number of advantages including high capacity, good cycling stability, low cost and can potentially be easily up-scaled. However, hard carbon is still largely underinvestigated and its comprehensive study is of great importance. In particular, a mechanism of sodium ion intercalation should be thoroughly analyzed. Moreover, a controllable and reproducible technology for their synthesis is highly demanded.

The most commonly used precursor for hard carbons are saccharides, phenolic resins, pitch, starch and cellulose. The latter draw great attention due to its abundance and a bunch of carbon materials with various properties can be obtained from cellulose by changing synthesis conditions[2].

In this study, samples of hard carbon were synthesized from cellulose using two different approaches. In the first approach, the samples were obtained by hydrothermal carbonization of cellulose dispersed in water at 185 °C and further hydrochars pyrolysis at 1300 °C under argon atmosphere. In the second approach, dehydration of cellulose powder was performed at 295 °C in air with further pyrolysis at 1300 °C under argon atmosphere.

The morphology and microstructure of the obtained samples were characterized by X-ray scattering diffraction and scanning electron microscopy. Electrochemical methods were used to analyze the obtained materials and it was found that the samples demonstrated capacity more than 250 mAh/g. Charge storage behavior was estimated by linear voltammetry in anodic area at different sweep rates[3].

This work was supported by the Russian Science Foundation (Grant No. 17-73-30006).

References:

[1] Saurel, D., Orayech, B., Xiao, B., Carriazo, D., Li, X., & Rojo, T. (2018). From Charge Storage Mechanism to Performance: A Roadmap toward High Specific Energy Sodium‐Ion Batteries through Carbon Anode Optimization. Advanced Energy Materials, 1703268.

[2] Yamamoto, H., Muratsubaki, S., Kubota, K., Fukunishi, M., Watanabe, H., Kim, J., & Komaba, S. (2018). Synthesizing higher-capacity hard-carbons from cellulose for Na-and K-ion batteries. Journal of Materials Chemistry A, 6(35), 16844-16848.

[3] Wang, J., Polleux, J., Lim, J., & Dunn, B. (2007). Pseudocapacitive contributions to electrochemical energy storage in TiO2 (anatase) nanoparticles. The Journal of Physical Chemistry C, 111(40), 14925-14931.
Etching-Assisted Crumpled Graphene and Graphene Wrapped Spiky Iron Oxide Particles for Li-Ion Hybrid Supercapacitor
Authors: Son Jeong Gon
Published: February 2020

From graphene oxide wrapped iron oxide particles with etching/reduction process, high-performance anode and cathode materials of lithium-ion hybrid supercapacitors are obtained in the same process with different etching conditions, which consist of partially etched crumpled graphene (CG) wrapped spiky iron oxide particles (CG@SF) for a battery-type anode, and fully etched CG for a capacitive-type cathode. The CG is formed along the shape of spikily etched particles, resulting in high specific surface area and electrical conductivity, thus the CG-based cathode exhibits remarkable capacitive performance of 210 F g−1 and excellent rate capabilities. The CG@SF can also be ideal anode materials owing to spiky and porous morphology of the particles and tightly attached crumpled graphene onto the spiky particles, which provides structural stability and low contact resistance during repetitive lithiation/delithiation processes. The CG@SF anode shows a particularly high capacitive performance of 1420 mAh g−1 after 270 cycles, continuously increases capacity beyond the 270th cycle, and also maintains a high capacity of 170 mAh g−1 at extremely high speeds of 100 oC. The full-cell exhibits a higher energy density up to 121 Wh kg−1 and maintains high energy density of 60.1 Wh kg−1 at 18.0 kW kg−1. This system could thus be a practical energy storage system to fill the gap between batteries and supercapacitors.
Development of Low Cost Synthesis Route to Sodium Transition Metal Sulfate Systems
Authors: Driscoll Elizabeth Helen , Driscoll Laura Louise , Slater Peter Raymond
Published: February 2020

Efficient energy storage devices have come into the spotlight for both consumer devices, transport and large scale grid applications. Whilst Li-ion batteries are a popular choice for the portable electronics and transport market, Na-ion batteries are attracting significant attention for potential use in large scale grid storage, due to showcasing a similar chemistry to lithium but at a lower cost.

Of particular interest are sulfate-based systems due to the advantageous inductive effect of the polyanion influencing the redox couples. Thus on this theme, one notable example which has attracted attention is alluaudite-type Na2Fe2(SO4)3whereby the Fe2+/Fe3+ redox delivered 3.8 V – the highest known redox couple for a sulfate system.1 Work by Driscoll et al., showed that new alluaudite systems, Na3M1.5(SO4)3-x(SeO4)x, could be obtained through dehydration of selenate doped Na2M(SO4)2.2H2O (M = Mn, Fe, Co and Ni).2 In this poster, we present an extension of this work, highlighting the relationship between the obtained structure type on dehydration and the metal cation size/polyanion size.

1 P. Barpanda, G. Oyama, S. I. Nishimura, S. C. Chung and A. Yamada, Nat. Commun., 2014, 5, 1–8.

2 L. L. Driscoll, E. Kendrick, K. S. Knight, A. J. Wright and P. R. Slater, J. Solid State Chem., 2018, 258, 64–71.

Figure 1
Facial Strategy to Production of Pomegranate like Fe3O4 Nano Assembly Embedded 2D-Crumpled Porous Carbon Sheets for a High-Performance Supercapacitor
Authors: Venkateswarlu Sada , Mahajan Hansa , Yoon Minyoung
Published: February 2020

Environmental global warming is a big crisis, due to copious development of industries and depletion of fossil fuels generate deteriorating environmental pollution and appalling economic crisis. Up to now, many materials were developed for electrochemical energy storage. Albeit, there are increasing unmet for developing new technologies for efficient, renewable energy sources based on sustainable storage devices. Herein, we firstly report a unique and facile method to convert agro bio-waste into a wealth economical material. Renewable waste garlic husk (Allium sativum) used for the synthesis of The Fe3O4 MNAs@2D-CCS composite (magnetic nano-assembly (MNAs), 2-dimensional crumpled carbon sheets). Most importantly, no harmful solvents were used, and no secondary waste was generated in the preparation of these nanophase composite materials. The XPS analysis and STEM-EDS line profile reveal the formation of the composite. The Fe3O4 MNAs@2D-CCS composite shows high surface area 687 m2 g-1 and a high specific capacitance of 840 F g-1 at a current density of 0.5 A g-1 and outstanding cycle stability with 90.1% retention of its initial specific capacitance after 2000 cycles, which is better than most of the reported Fe3O4 capacitors. It was found that the Fe3O4 MNAs@2D-CCS composite exhibit high specific capacitances and excellent cycle stability than those of pristine Fe3O4 and pure CCS. Thus, the eco-friendly, economically viable method stimulate a new door for the generation of waste to valuable materials for energy, catalysis, and environmental applications.

Figure 1
Application of the Hybrid-Ion Battery Concept to Selected Oxide Systems
Authors: Maletti Sebastian , Mikhailova Daria
Published: February 2020

The success of Li-ion batteries led to a steady growth of applications that rely on this energy storage technology. However, the non-abundancy of necessary resources requires the establishment of successor technologies such as Na- or Mg-ion batteries. Both are still missing a breakthrough due to a variety of issues. Recently, the concept of hybrid batteries, which is based on a combined operation of two kinds of cations, has been proposed, bridging the gap between lithium and post-lithium energy storage [1]. Its main idea is to restrict chemical processes of one cation type to only one electrode while the other cation type takes part in processes on the other electrode. This results in the replacement or significant reduction of lithium amounts in a battery. Focusing on Li+, Na+ and Mg2+ ions as charge carriers, three types of hybrid batteries can be considered as Mg-Li, Mg-Na and Na-Li batteries. Currently, the main challenges are the search of a suitable electrolyte system compatible with both anodes and cathodes, as well as obtaining acceptable long-term cycling behavior, which is influenced strongly by many factors such as different SEI compositions.

We studied different types of hybrid batteries with non-aqueous dual salt electrolytes using well-known electrode materials like Li4Ti5O12, TiNb2O7, LiFePO4 and LiV3O8 with the aim to evaluate issues concerning individual materials as well as general correlations referring to the certain type of a hybrid system. For example, we investigated LiV3O8 cathodes in mixed Na-Li electrolytes and found structural changes and the electrochemical behavior to be strongly influenced by the Li/Na ratio (Fig. 1). By obtaining higher capacities than in pure Na-ion batteries and better cycling behavior than in Li-ion batteries, we demonstrated that this concept represents a good compromise between these battery types. However, observed lithium plating on sodium anodes seems to be a general weakness of the hybrid Na-Li battery for the given electrolyte compositions, which has to be overcome [2]. Mg-Li batteries were studied using TiNb2O7 and Li4Ti5O12 operating at intermediate potentials that yielded promising results (Fig.2). A careful examination of structural evolution and the composition in a subsurface region revealed Li+ selectivity for bulk intercalation while Mg2+ is restricted to the anodic reaction. When aiming at higher voltages, electrolytes capable of depositing and stripping Mg become either unstable or reactive towards non-inert current collectors, but the applicability of LiFePO4 and LiV3O8 in dual salt electrolytes using special setups could be demonstrated. For the Mg-Na combination, we studied layered sodium oxides in a broad voltage range, and showed capability of desodiation of the layered structures and anodical deposition of Mg. However, the reverse reaction occurs at significantly lower discharge potentials with a large polarization.

Figure 1
The Marriage of Solid-State Electrolyte and Safe Lithium Metal Anodes in a Working Battery
Authors: Zhang Qiang
Published: February 2020

Li metal is extensively focused due to its ultrahigh theoretical capacity (3860 mAh g−1, 10 times higher than that of graphite) and the most negative electrochemical potential (−3.040 V versus standard hydrogen electrode). Solid-state electrolyte exhibits enhanced safety relative to non-aqueous electrolyte. Therefore, the marriage of Li metal and solid-state electrolyte is expected to inherit the merits of both. However, the competitive solid-state lithium metal batteries encounter formidable challenges, including dendrite issues and poor solid-solid contact. Investigating the interdisciplinary issues of solid-state electrolyte and Li metal in integrated cells is necessary to realize the efficient and safe solid-state lithium metal batteries.

This talk focuses on the energy chemistry issues generated from the marriage of Li metal and solid-state electrolyte, instead of their respective problems. Firstly, the issues generated from the marriage of lithium metal anode and solid-state electrolyte. Specific attentions are paid to the large interfacial resistance, uncontrolled dendrite growth, and low operation current/capacity. The primarily understanding the ionic channels in the composite electrolyte and space charge layers in the interfacial region are also included. Based on these dilemmas and working principles, emerging strategies to render solid-state lithium metal batteries are introduced. Finally, the general conclusion and perspective on the current limitations and recommended research of solid-state lithium metal batteries are presented.

References

1. Cheng XB, Zhao CZ, Yao YX, Liu H, Zhang Q. Chem 2019, doi: 10.1016/j.chempr.2018.12.002.

2. Cheng XB, Zhang R, Zhao CZ, Zhang Q. Chemical Reviews 2017, 117, 10403–10473.

3. Zhao CZ, Zhang XQ, Cheng XB, Zhang R, Xu R, Chen PY, Peng HJ, Huang JQ, Zhang Q. Proceedings of the National Academy of Sciences of the United States of America (PNAS) 2017, 114, 11069-11074.

4. Cheng XB, Huang JQ, Zhang Q. A Review of Li Metal Anode in Working Lithium-Sulfur Batteries. Journal of the Electrochemical Society 2018, 165, A6058-A6072.

5. Zhang R, Chen X, Shen X, Zhang XQ, Chen XR, Cheng XB, Yan C, Zhao CZ, Zhang Q. Joule 2018, 2, 764-777.

6. Yan C, Cheng XB, Yao YX, Shen X, Li BQ, Li WJ, Zhang R, Huang JQ, Li H, Zhang Q. Advanced Materials 2018, 30, 1804461.

7 Zhao CZ, Chen PY, Zhang R, Chen X, Li BQ, Zhang XQ, Cheng XB, Zhang Q. Science Advances 2018, 4, eaa3446.

8. Chen X, Li HR, Shen X, Zhang Q. Angewandte Chemie International Edition 2018, 57, 16643-16647.

9. Cheng XB, Yan C, Chen X, Guan C, Huang JQ, Peng HJ, Zhang R, Yang ST, Zhang Q. Chem 2017, 2, 258-270.

10. Cheng XB, Zhang R, Zhao CZ, Wei F, Zhang JG, Zhang Q. Advanced Science 2016, 3, 1500213.
Synergistic Effect of Sulfur Electrode Technology and Nature of Anode Materials to Increasing the Energy and Reducing Self - Discharge the Battery Based on Sulfur Cathode
Authors: Shembel Elena , Markevich Alexandr V , Kolomoyets Olga , Redko Vlad Ivanovich , Pastushkin Timothy V , Straková Fedorková Andrea , Polishchuk Yuliya , Girin Oleg , Kirsanova Irina Viktorovna , Maksyuta Irina M , Zaderey Nelya
Published: February 2020

The goal of the achievements that will be presented is to illustrating how nature on the anode material and technology fabrication the cathode based on the sulfur, can dramatically influence on the properties battery with cathode based on the sulfur:

- Increasing the energy

- Decreasing the self-discharge

- Increasing the safety.

Among important parameters of technology to fabricating Sulfur cathode have been taking in mind the following:

Nature of sulfur: dispersion sulfur or polymeric sulfur;

Conductivity of carbon (graphite and black) that are included in cathode mass;

Resistance of interface between current collector and layer of the cathode electrode mass.

Design of cathode.

As the anode materials have been used not only lithium, but also other anode materials that can results in decreasing the self-discharge battery with sulfur cathode:

- Composition of silicon and graphite that is without binder

- Magnesium alloys

Silicon – graphite composite anode have been fabricated via a proprietary method of gas detonation deposition that developed by Enerize

For evaluation the properties of initial materials, semi-product and final product Enerize developed and used non-destructive non-contact method and devices. This allows insuring the properties the components of electrodes and properties of final product – battery

During presentation will be illustrated and described the parameters of developed battery with Sulfur based cathode.

Acknowledgements. This presentation is connected with the framework of NATO, Science for Peace and Security Programme Project SPS 985148 “Development of New Cathodes for Stable and Safer Lithium-Sulfur Batteries” in the light of development the innovating batteries with high energy and low self - discharge that are based on Sulfur cathode and various type anode. Enerize Corporation is the Industrial Partner / End User of this NATO project. Ukrainian State University of Chemical Technology is active participant of this NATO project. The work was also carried out according to the project of the Ministry of Education and Science of Ukraine, project No. 42/170790 "Development of high energy power sources based on Ukrainian magnesium and manganese raw material for innovative instrumentation”