bluuebunny/crossref_metadata_2025_split huggingface dataset:
Aqueous Alkali Metal-Ion Battery with Hexacyanometallate Electrodes and Concentrated Electrolyte
Authors: Nakamoto Kosuke , Sakamoto Ryo , Sawada Yuki , Zhao Liwei , Ito Masato , Okada Shigeto 
Published: February 2020

Aqueous alkali metal-ion batteries have attracted much attention, because they have three major advantages, namely non-flammability, high ionic conductivity and low cost. In addition, water can dissolve various salts in large amounts to provide a variety of electrolytic solutions. On the other hand, the 1.2 V theoretical electrochemical window of water restricts the selection of the cathode and anode active materials. However, three years ago, this issue was first addressed by U.S. Army Research Laboratory [1]. They successfully expanded the cell voltage of the aqueous Li-ion battery more than 2 V by introducing highly concentrated electrolytes, which effectively suppressed undesired electrolysis of water. To confirm the electrochemical window expansion of the concentrated electrolyte even in Na system, we also tried to realize a high voltage aqueous Na-ion battery by concentrated aqueous electrolyte. In preliminary measurement, 1.4 V average discharge voltage was obtained in the combination of Prussian blue-type Na2Mn[Fe(CN)6] (NMHCF) cathode and NASICON-type NaTi2(PO4)3 (NTP) anode with concentrated (17 mol/kg) NaClO4 aqueous electrolyte [2]. However, according to a CV measurement, the electrochemical window was almost 2.8 V [2]. Therefore, in order to further raise the cell voltage, instead of NTP anode based on Ti4+/Ti3+ redox, Prussian blue-type KMn[Cr(CN)6] (potassium manganese hexacyanochromate; KMHCC) anode based on Cr3+/Cr2+ redox was adopted. Then, 2 V class aqueous Na-ion battery was successfully obtained [3].
As this analogy, we have newly found the rechargeable operation of the aqueous K-ion battery in the combination of Prussian blue-type K2Mn[Fe(CN)6] (potassium manganese hexacyanoferrate; KMHCF) cathode and KMHCC anode with highly concentrated potassium triflate (19 mol/kg KSO3CF3; KOTf) aqueous electrolyte. The average cell voltage was approximately 1.5 V and the specific capacity was 118 mAh/g-KMHCF and 60 mAh/g-KMHCC, respectively. However, the two similar full cells suffered from capacity fading caused by degradation of Prussian blue-type structure induced by side reaction such as electrolysis of water solvent or electrolyte salt decomposition. The mechanism of degradation and our trial to improve the cyclability by changing the condition such as charging rate, cell configuration, electrolyte or its additives will be discussed in presentation.
References
[1] L. Suo, O. Borodin, T. Gao, M. Olguin, J. Ho, X. Fan, C. Luo, C. Wang, and K. Xu, Science, 350 (2015) 938-943.
[2] K. Nakamoto, R. Sakamoto, M. Ito, A. Kitajou, and S. Okada, Electrochemistry, 85(4) (2017) 179-185.
[3] K. Nakamoto, R. Sakamoto, Y. Sawada, M. Ito, and S. Okada, Small Methods, (2018) 1800220.
All Organic Interface Layer Formed from Vinylene Carbonate and Stable Plating of Lithium Metal
Authors: Zhou Hongyao , Liu Haodong , Liu Ping 
Published: February 2020

Prevailing demand for lithium-ion batteries with higher energy density draws more researcher's attentions on the use of lithium metal as the anode material. An order of magnitude higher specific capacity and much lower reduction potential of lithium metal compared to graphite makes lithium metal suitable anode for the next-generation lithium-sulfur and lithium-air batteries. However, nonuniform plating or dendrite formation of lithium metal is a major issue for shorting batteries. Stable interface between lithium metal and electrolyte is the key to the uniform growth of lithium. Vinylene carbonate (VC) is a widely used additive in commercial electrolyte for lithium-ion batteries, and the effect of VC on stabilizing lithium metal has been reported. VC is proposed to polymerize on lithium surface to form flexible thin coating layer, which regulates the lithium-ion flux at the interface and put a mechanical pressure on the growing lithium dendrite. The interface layer is composed of multiple decomposition products from organic solvents and fluorinated salt and extremely complex to analyze.
Here we propose a gel electrolyte composed of vinylene carbonate and lithium iodide (LiI) to form polymer coating layer on the lithium surface. FTIR, NMR, and GC-FID analysis confirm polymerization of vinylene carbonate is triggered by lithium iodide through decarboxylation and forms poly(vinylene catbonate). Because iodide is electrochemically irreducible anion, no decomposition occurs on the lithium surface and simplifies the interface composition. Without the formation of inorganic compounds in VC-LiI gel electrolyte, Li//Li symmetric cell cycles for 1000 hours at 1 mA cm-2 and 1 mAh cm-2, with a practical electrolyte thickness of 25 μm (separator free). Coulombic efficiency of lithium plating/stripping in VC-LiI gel electrolyte is 98.6%, which is significantly higher than conventional carbonate-based electrolyte. Cross-sectional SEM image of cycled lithium metal reveals dense polymer coating and dendrite free morphology. Therefore, the simple all-organic interface, differing from conventional heterogeneous inorganic/organic mixture, can stabilize the lithium surface. We present a new perspective on the design of electrolyte and lithium interface.
Understanding the Impact of Composition and Processing on Tortuosity and Electrochemical Performance for Li-Ion Battery Electrodes
Authors: Seeba Jann , Reuber Sebastian , Wolter Mareike , Michaelis Alexander 
Published: February 2020

Li-ion batteries (LIBs) are considered as the suitable technology for electric vehicles, as they offer a combination of power and energy density.
Research principally aims to improve the energy density, e.g. by increasing the specific energy density of the active material. Another approach to enhance the cells energy density is to increase the ratio of active material to inactive parts, for example by increasing the electrodes coating thickness. However, by enhancing the thickness the diffusion length of Li-ions extends which impairs the cells rate capability significantly. To tackle this problem the electrode design has to be optimized
The diffusion path in electrodes is described by the tortuosity parameter, which is defined by the deviation from the shortest diffusion path. By knowing the electrodes tortuosity, the rate capability of thicker electrodes can be optimized within the production process.
In the past the tortuosity was only accessible by tomographic measurements, which are time consuming and have a boundary in resolution or sample size. Newly developed electrochemical methods have been described in the literature, that allow a simple measurement of tortuosity, enabling comprehensive analysis of influences on tortuosity
We present a systematic study of the influence of composition and processing on the tortuosity. For the composition different active materials and conductive additives are evaluated. Furthermore, the impact of different processing of materials is evaluated, for example a change from tape casting with low viscosity slurries to an extrusion based coating process with high viscosity pastes.
Main aim is to improve the rate capability of thick electrodes. This is done by comparing the acquired tortuosity with the measured electrochemical test. Results show small changes in composition can lead to better rate capability with minimal sacrifice of capacity. Lastly, potential impact on the cycle life will be considered, to avoid a sacrifice in cycle life time.
Working Toward Faster Charging Lithium-Ion Cells through Electrolyte Chemistry
Authors: Hall David S , Logan Eric R. , Eldesoky Ahmed , Tonita Erin M. , Ma Xiaowei , Dahn Jeff R 
Published: February 2020

As the adoption of electric vehicles continues to increase, there is a growing demand for faster charging lithium-ion cells to compete with the convenience of fuel-powered vehicles. Yet even for modern designs, rapidly charging lithium-ion cells can cause a decrease in cycle and calendar lifetimes. This is largely attributable to the large overpotentials required to apply large currents, which can lead to unwanted lithium metal plating at the graphite electrode surface. Moreover, as electrode thickness increases for higher energy density cells, lithium-ion transport in the electrolyte becomes limited, leading to even larger overpotentials. This work will present novel electrolytes with improved lithium-ion transport properties. Several co-solvent systems were identified based on the viscosity, permittivity (dielectric constant), and DFT-calculated electrochemical stability windows of the pure compounds. Several formate, nitrile, ketone, and amide co-solvents will be shown to increase the ionic conductivity of LiPF6 in conventional organic-carbonate-based solutions (Figure 1). Based on gas production during the first formation cycle in Li[Ni1-x-yCoxAly])2/graphite-SiO pouch cells, five candidates were identified: methyl formate (MF), ethyl formate (EF), propionitrile (PN), isobutyronitrile (iBN), and dimethyl formamide (DMF). High temperature storage (60°C), ultrahigh-precision coulometry (UHPC), and long-term cycling results will be presented showing that MF offers the greatest balance between conductivity increase and cell lifetime. PN may prove useful for low temperature (< 40°C) applications.
Figure 1 – a) Ionic conductivity of 1.2 mol L−1 LiPF6 solutions prepared with 20% of co-solvent and 80% of a 25:5:70 mixture by weight of ethylene carbonate, ethyl methyl carbonate, and dimethyl carbonate, respectively. b) Solution conductivities relative to control solution, i.e., no co-solvent. Co-solvents include isobutyl acetate (iBA), methyl propionate (MP), methyl butyrate (MB), methyl formate (MF), ethyl formate (EF), n-propyl formate (nPF), isobutyl formate (iBF), propionitrile (PN), isobutyl nitrile (iBN), methyl ethyl ketone (MEK), and dimethyl formamide (DMF).

Figure 1
Analysis of Transport Properties of Polycarbonate-Based Polymer Electrolytes Containing Lithium (perfluoroalkylsulfonyl)Imides for Possible Application in Lithium-Ion Batteries
Authors: Gerlitz Anna Isabella , Buchheit Annika , Grünebaum Mariano , Wiemhöfer Hans-Dieter 
Published: February 2020

The search for safe electrolytes for the use in lithium metal batteries and high energy density batteries has driven the interest in alternative polymer electrolytes with enhanced performance. The central interest focuses on transport properties as good ionic conductivities and on high electrochemical stability towards lithium metal anodes and cathodes for high voltage batteries. To gain insight in the Li-ion movement in polycarbonates, as dry or gel electrolyte, is necessary for understanding how to improve these systems and achieve better performances. In this context, we present a critical study on polycarbonates as alternative to polyethylene oxide (PEO) in salt-in-polymer electrolytes. [1]

Polymer electrolytes based on PEO as well as some related with grafted PEO side chains along polymer backbones such as polyphosphazenes, polysiloxanes and others are known to reach ionic conductivities in the range of 10-3 - 10-4 S·cm-1 in a favourable temperature range and typical Li+ transference numbers around 0.2.[2,3] In contrast to that, polycarbonates were reported to exhibit transference numbers up to about 0.5 as well as higher ionic conductivities and electrochemical stability.[4]

In this work, the commercially available polycarbonates polyethylene carbonate (PEC) and polypropylene carbonate (PPC) were prepared as flexible self-standing membranes with dissolved fluorinated lithium salts such as LiTFSI and others. With the use of propylene carbonate (PC) novel gel-polymer electrolytes have been fabricated. The ion conducting polymer membranes were examined regarding their electrochemical and transport characteristics with respect to possible battery applications. We studied ionic conductivity and Li-ion transference number as well as the coordination of lithium with different dissolved lithium salts on carefully purified polycarbonate samples. We obtained ionic conductivities in dry state around 10-6 S·cm-1 at room temperature and up to 10-3 in gelled systems. The novel gel systems based on PEC and PPC perform significantly better than the dry alternatives.

Acknowledgements

The authors acknowledge the funding within the project BenchBatt (03XP0047A) by the German Ministry of education and research. We are also grateful for the support by the Helmholtz Association within the Helmholtz Institute Münster (HI MS).
[1] P. Knauth, Solid State Ionics, 180 (2009) 911-916.
[2] M. Grünebaum, M.M. Hiller et al., Prog. Solid State Chem. 42 (2014) 85–105.
[3] M. Hiller, M. Joost et al., Electrochim. Acta 114 (2013) 21-29.
[4] Y. Tominaga, K. Yamazaki, Chem. Commun. 50 (2014) 4448-4450.
Electrochemical Behavior of TiO2 Coating on Ncm Cathode Material for All-Solid State Batteries
Authors: Ban Hee-Jung , Jung Ha-Young , Ryu Hye-Min , Park Sang-Jun , Kim Min-Young , Song Young-Woong , Jeon Se-Hyeon , Nam Su-jeong , Kim Ho-Sung , Kim Yoong-Ahm 
Published: February 2020

Recently, the demand for the middle- or large-sized lithium batteries with safety has increased. To solve this problem, all-solid state batteries (ASSBs) are actively researched. However, it is known that the ASSBs has a higher interfacial resistance than the conventional lithium batteries. Also, the ASSBs are operated at a high temperature of 60 to 80 °C, resulting in the degradation of the cycle performance due to the collapse of the structure of the active material.
In this study, NCM materials were coated with TiO2 via sol-gel process. The crystal structure and surface morphology were observed according to TiO2 content and calcination temperature using X-ray diffraction (XRD), Scanning electron microscope (SEM), and Transmission electron microscope (TEM). Moreover, ASSBs were fabricated by using the TiO2-coated NCM as cathode, composite electrolyte (CE) and lithium metal as anode. Electrochemical characteristics were evaluated on the all-solid cells at 70°C, 0.1C. As a result, it has been found that the lattice parameters and crystal size of the NCM bulk are affected by the sintering temperature and the TiO2 coating content, which also affects the discharge capacity and cycle characteristics of the cells. We describe about the electrochemical behavior of NCM coatings by TiO2 in ASSBs in more detail.
Improving the Cycling Stability of Ni-Rich Layered Cathode Material By Introducing Redox Shuttle Electrolyte Additives
Authors: Zhu Xinhua , Revilla Reynier I. , Bheemireddy Narendraprasad Reddy , Hubin Annick 
Published: February 2020

A systematic post-mortem analysis on a batch of power-optimized commercial LiNi0.80Co0.15Al0.05O2 (NCA) electrodes with different aging conditions was conducted. This aging study provides direct evidence that the intrinsic surface heterogeneity, resulting in locally overcharge reactions, plays a critical role in the degradation of NCA electrodes.
Accordingly, we propose a counter measure, adding redox shuttle electrolyte additive (RSA), to improve the cycling stability of Ni-rich layered cathode materials. The RSA can effectively balance the inhomogeneously distributed state-of-charge by shuttling excess charges between overcharged particles and normal charged particles. The unfavorably local overcharging reactions are thus inhibited. As indicated in the experimental results, with a small amount (0.025 M) of RSA 1,4-di-tert-Butyl-2,5-bis(2,2,2-trifluoroethoxy)benzene, the cycling performance of the commercial Nickel-rich cathode materials is improved about 30% in practical utilizing conditions as shown in the figure. There is a great potential for exploiting this approach in all kinds of commercial lithium-ion battery systems containing a liquid electrolyte. Furthermore, the remarkable effectiveness of the RSA approach further justifies the crucial role that the surface inhomogeneity plays in the cycling aging. Therefore, this issue deserves more attention in future aging studies of lithium-ion batteries.

Figure 1
Development of Foam-Based 3D-Electrodes for High Power All-Solid State Batteries
Authors: Bardenhagen Ingo , Glenneberg Jens , Gräfenstein Alexander , Speckmann Björn , Stenzel Volkmar , Schwenzel Julian 
Published: February 2020

Conventional lithium ion battery concepts are based on two-dimensional electrode structures. They usually comprise electrodes consisting of active material layers deposited on metallic foils that are stacked together with polymer-based separators and soaked with liquid electrolyte.
The concept presented here in contrast makes use of three-dimensional, foam-based structures as substrates for the deposition of the active material layers. The large inner surface of the foams allows for a drastical increase of the available surface area for ion exchange. This allows for high power applications, even when the ionic conductivity of the electrolyte is limited, as is the case for many solid-state electrolytes. Because of the high porosity of the foams of 95% and above, the volumetric energy density can still be kept at a high level in this concept.
The research presented here reports the development of novel three-dimensional, foam-based electrodes for application in lithium ion batteries with liquid or all-solid state electrolytes. By their specialized design, these electrodes are capable of delivering both high power and high energy. Requirements for the foam design are derived from application demands. Next, the foam substrates are coated with active material layers and assembled into cells for proof of concept. Different coating concepts and the impact of pore size and foam material are evaluated. And outlook on all-solid state battery concepts extending the liquid-electrolyte approach is given as well.
The work presented here is part of the project ‘Batt3D’. Financial support by the German Federal Ministry of Economic Affairs and Energy is gratefully acknowledged.

Figure 1
Characterization of Battery Material Interfaces By Time-of-Flight Secondary Ion Mass Spectrometry
Authors: Walther Felix , Koerver Raimund , Fuchs Till , Ohno Saneyuki , Sann Joachim , Rohnke Marcus , Zeier Wolfgang G. , Janek Jürgen 
Published: February 2020

Energy storage is one of the key issues in the context of renewable energy. Fluctuations in energy production due to the dependence on external conditions, such as the weather, complicate the predictability in the energy supply and the progress in the transition to renewable energy. In this context, batteries based on Li ions are one of the most promising candidates to solve this problem. Also the application in the automotive sector is of general interest, but suffers from limited acceptance in society due to the relatively short range of electric vehicles and long battery charging times.[1]

Progress in the field of Li ion based batteries requires a better understanding of the underlying degradation mechanisms to further increase the battery performance. Therefore, cycling stability needs to be improved and related issues, such as capacity fading, must be solved in order to reduce costs and resource consumption. Investigations regarding the degradation on the interface between the electrodes and the electrolyte are challenging since several materials are contributed in low concentrations and a high lateral resolution is required to determine the local material distribution. Typically, such investigations are based on electrochemical studies, diffraction methods, microscopic investigations and computational methods.[2-4] In contrast, the measuring possibilities of analytical methods such as time-of-flight secondary ion mass spectrometry (ToF-SIMS) are yet not fully exploited.
In this work, we demonstrate that ToF-SIMS can make a significant contribution to the elucidation of degradation processes in batteries. This includes the establishment of ToF-SIMS in optimization processes of individual battery components and the characterization of degradation. Next to surface analysis and conventional depth profiling, we used surface imaging with delayed extraction combined with sputtering to enable analytical 3D tomography of coated particles with simultaneously high lateral resolution up to 100 nm and high mass resolution (m/∆m = ~ 5000). FIB-SIMS tomography was applied to check the particle morphology. The samples examined include cathode and anode materials, such as coated Li[Ni
x
Co
y
Mn
z
]O2 particles (NCM with x + y + z = 1) and graphite.
In summary, we demonstrate that ToF-SIMS is a valuable tool for the tomographic study of battery materials. In combination with delayed extraction, ToF-SIMS can be used to reveal structural information in batteries in the nm range that are not easily accessible by other techniques.
[1] E. Dütschke et al., Technologie-Roadmapping am Fraunhofer ISI: Konzepte - Methoden - Praxisbeispiele, 3, 2012.
[2] B. Wu et al., J. Mater. Chem. A Mater. energy Sustain., 2016, 4, 15266–15280.
[3] A. O. Kondrakov et al., J. Phys. Chem. C., 2017, 121 (6), 3286–3294.
[4] Y. Zhu et al., J. Mater. Chem. A., 2016, 4, 3253-3266.
Vanadium-Based Polyoxometalate As Anode Materials for Lithium–Ion Capacitors
Authors: Huang Shao Chu , Lin Chia Ching , Chen Han Yi 
Published: February 2020

Because of the increasing demand for portable devices, renewable energy systems, and electric vehicles, energy storage system has been developed intensively over the past decade. Researchers have intensively studied low-cost, high energy density, high power density, and high-safety energy storage devices. Lithium-ion batteries (LIBs) have advantages of high energy density and no memory effect. However, the power density is relatively low. In contrast to LIBs, supercapacitors (SCs) exhibit high power density and long cycling life, but low energy density. Therefore, lithium ion capacitors (LICs) which combine the superiorities of LIBs and SCs has been announced recently in order to achieve both high energy density and power density.
Polyoxometalates (POMs) are a class of anionic polynuclear transition metal oxides, and they possess multiple redox reactions which can store many charges per molecule. Hence, POMs have been employed as electrode materials for energy storage devices, such as LIBs, sodium-ion batteries (NIBs), and SCs, and most of them exhibit high capacity.
In this work, a vanadium-based POM (V-POM) was utilized as anode material for LICs. V-POM exhibited high specific capacities as well as good cycling stability. A full cell comprised with V-POM anode and porous carbon cathode were assembled, and it showed high energy density and high power density. These results demonstrated that V-POM anode material is suitable for LIC applications. Furthermore, we also utilized several in operando techniques to investigate the charge storage mechanisms of this V-POM anode including X-ray Absorption Spectroscopy and X-ray diffraction.