bluuebunny/crossref_metadata_2025_split huggingface dataset:
Improved High Voltage Electrochemical Properties and Thermal Stability of LiNi0.6Co0.2Mn0.2 By Li3PO4 Surface Modification
Authors: Lee Suk-Woo , Kim Myeong-Seong , Youn Hee-Chang , Kim Young-Hwan , Kim Jisoo , Kim Kwang-Bum 
Published: February 2020

LiCoO2 is the most commercialized in lithium ion batteries (LIBs) for portable electronics because of its high volumetric energy density compared to the other commercialized cathode materials. However, low specific capacity (145 mAh/g @ 4.3 V cut-off) hinders its application to emerging technologies, such as power tool and plug-in hybrid electric vehicles. As a result, layered Ni-rich LiNixCoyMn1
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x
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yO2 materials have attracted much attention as promising alternative cathode materials because of their high capacity and relatively low cost. However, Ni-rich layered cathode materials suffer from structural instability by direct contact with electrolyte at high voltage (>4.3V), resulting in poor cyclability, rate capability and thermal instability.
To solve these problems, a lot of researches have been carried out to coat the surface of layered cathode materials using oxide or phosphate, such as TiO2, Al2O3, and Li3PO4.
Among these coating materials, Li3PO4 has attracted a great attention as coating material due to its high ionic conductivity and thermal stability due to strong P=O bonding.
Recently, Zhao et al., reported on the Li3PO4 coating on LiFePO4 cathode material, but they used Li3PO4 nano particle as a coating material, resulting in non-uniform coating. Also, Xiong et el, tried to coat the Li3PO4 on LiNi0.8Co0.1Mn0.1O2 cathode material using the reaction between (NH4)2HPO4 and lithium residues, but the Li3PO4 coating layer is not confirmed.
In this study, we report on the synthesis of Li3PO4-coated LiNi0.6Co0.2Mn0.2O2 using a citric acid assisted sol-gel method in which nm-thick Li3PO4 layer was uniformly coated on the LiNi0.6Co0.2Mn0.2O2. It exhibited improved cyclability at high voltage (4.7V) and rate capability than those of bare LiNi0.6Co0.2Mn0.2O2. In addition, Li3PO4-coated LiNi0.6Co0.2Mn0.2O2showed improved thermal stability at elevated temperature.
More details on the synthetic procedure, electrochemical and physical properties will be presented at the meeting.
Crystallographic Analysis of Structural Changes in Lithium Nickel Manganese Cobalt Oxides at Different Stages of Lithiation
Authors: Fröhlich Katja , Kahr Jürgen , Abrahams Isaac , Trifonova Atanaska 
Published: February 2020

Mixed transition metal oxides are among the most promising cathode materials for lithium ion batteries. The high specific capacity, low cost and thermal stability makes Li(Ni1/3Mn1/3Co1/3)O2, so-called NMC, an excellent material for power tool applications. Therefore, main leading battery manufacturer focus on the combination of these three transition metals to combine the strengths of each of them [1].
The development and design of battery materials require deep understanding of the relations between chemistry, structure and its properties. Nowadays, the commercialized NMC can only reach around 60 % of its theoretical capacity when cycled up to 4.2 V. Higher specific capacities might be reached when the upper voltage limit is raised up to 4.5 V [2], but the lifetime of the cathode then decreases drastically. The deintercalation of more than 0.6 moles of lithium in the charge process of the battery leads to irreversible capacity losses.
Lithium nickel manganese cobalt oxides with different transition metal ratios were successfully synthesized via coprecipitation route. The cathode materials were characterized physico- and electrochemically and the composition was confirmed via inductive coupled plasma atomic emission spectroscopy (ICP-AES).
Structural changes of non-symmetric NMC compounds at different stages of lithiation were recorded using x-ray diffraction. The resulting patterns were analyzed and the structures refined using the Rietveld method implemented in the GSAS (General Structure Analysis System) package [3].
The same procedure of crystallographic characterization of the NMC structure was carried out for different transition metal ratios cycled up to 4.5 V. The results are presented and comparison between symmetric and non-symmetric lithium nickel manganese cobalt oxides will give better insight into structural changes at higher voltages and the relation to their compositions.
Acknowledgement
This work was financially supported by the Austrian Federal Ministry for Transport, Innovation and Technology (bmvit) and the Austrian Research Promotion Agency (FFG).
[1] N. Yabuuchi, T. Ohzuku, Journal of Power Sources 119-121 (2003): 171-174
[2] Q. Yu, Z. Chen, L. Xing, D. Chen, H. Rong, Q. Liu,W. Li, Electrochimica Acta 176 (2015): 919-925
[3] A. C. Larson, R. B. Von Dreele, Los Alamos National Laboratory Report, No. LAUR-86-748, (1987)
On the Asymmetry of Charge-Discharge Curves of Lithium-Ion Battery Electrode Materials
Authors: Hall Florian , Wussler Sabine , Buqa Hilmi , Bessler Wolfgang G. 
Published: February 2020

One of the most auspicious materials for lithium-ion batteries is Nickel cobalt aluminum oxide (NCA). It provides a high capacity, excellent rate capability and low costs [1]. NCA-electrodes and NCA-based lithium-ion batteries have been observed to exhibit a distinct discharge/charge asymmetry in the low SOC regime, shown both in the published literature [2,3] and in our own full-cell (see Figure) and half-cell experiments.
The origin of this behavior has not yet been explained. Using elementary kinetics theory, we show that the asymmetry is caused by a two-step electrochemical reaction mechanism, where charge transfer is associated with electroadsorption of lithium ions from the electrolyte onto the NCA surface (s) according to
Li+(electrolyte) + e–+ (s) ⇄ Li(s),
followed by incorporation into the bulk active material,
Li(s) + V[NCA] ⇄ Li[NCA] + (s).
The overall reaction is dominated by the surface reaction, because of the limited surface spots. Both thermodynamics (via Nernst equation) and kinetics (transition state theory) of the electroadsorption reaction are nonlinearly influenced by surface concentrations of the involved surface species. Surface coverages, in turn, nonlinearly depend on the thermodynamics of the incorporation reaction, where different assumptions for the surface thermodynamics and bulk intercalation range are shown to cause different levels and shape of asymmetry.
The asymmetry is shown to prevail in commercial NCA/LTO pouch cells, leading to a strong temperature and rate sensitivity of the cell capacity. Newman-type numerical models that take the two-step behavior into account are able to reproduce experimentally-observed cell discharge/charge measurements over a wide range of temperature and C rate.
The Figure shows a) the experimental charge-discharge curves of a commercial cell in the low SOC regime, b) simulations using a standard model with single-step Butler-Volmer kinetics, and c) simulations using an extended model with an elementary kinetic two-step mechanism.
Literature:
1. W.-S. Yoon, K. Y. Chung, J. McBreen, and X.-Q. Yang, “A comparative study on structural changes of LiCo1/3Ni1/3Mn1/3O2 and LiNi0.8Co0.15Al0.05O2 during first charge using in situ XRD,” Electrochemistry Communications 8, 1257–1262 (2006).
2. P. Albertus, J. Christensen, and J. Newman, “Experiments on and Modeling of Positive Electrodes with Multiple Active Materials for Lithium-Ion Batteries,” J. Electrochem. Soc. 156, A606 (2009).
3. Y. Xu, X. Li, Z. Wang, H. Guo, and B. Huang, “Structure and electrochemical performance of TiO2-coated LiNi0.80Co0.15Al0.05O2 cathode material,” Materials Letters 143, 151–154 (2015).

Figure 1
Electrochemical Properties of Single Crystalline LiMn2O4 cathode Thin Films
Authors: Hendriks Theodoor Anton , Monteiro Cunha Daniel , Singh Deepak , Huijben Mark 
Published: February 2020

Most commercial rechargeable lithium-ion batteries deliver energy densities far below their theoretical values. The key problem determining these limitations are the slow electrode process kinetics, low ionic diffusion and low electronic conductivity, particularly at the electrode-electrolyte interfaces. Mastering control of these interfaces is identified as a grand challenge in battery research, even more important than designing new electrode and electrolyte materials.
All-solid-state microbatteries facilitate miniaturization, which will create more flexibility for the design of stand-alone microelectronic devices with enhanced applicability due to the avoided leakage risks. However, the successful application of all-solid-state microbatteries depends strongly on the enhancement of energy density and lifetime. The cycle-life and lifetime are dependent on the nature of the interfaces between the electrodes and electrolyte, whereas safety is a function of the stability of the electrode materials and interfaces. Therefore, perfect control on the interfacial properties between the electrodes and electrolyte is needed, but remains a great challenge.
The crystal structure of the electrode, electrolyte matrix and their interfaces will determine the lithium diffusion mechanism within the complete structure, which will eventually be crucial for the battery performance. To study the variation in electrochemical properties for the different crystalline directions in the spinel crystal structure of the LiMn2O4 cathode material, thin films have been grown by pulsed laser deposition. Control over the deposition parameters (temperature, pressure, etc.) in combination with variation in crystal orientation of the Nb-doped SrTiO3 substrates (e.g. (001), (111) and (110)) enabled the formation of single crystalline LiMn2O4 thin films.
The local variations in surface morphology and phase composition have been analyzed by Atomic Force Microscopy (AFM) and X-Ray Photoelectron Spectroscopy (XPS), while the variations in structural properties have been characterized by X-ray Diffraction (XRD). Electrochemical performance was studied by impedance spectroscopy.
In our study we have investigated the relation between the electrochemical performance and the crystal orientation in LiMn2O4 cathode thin films. This provides important insight for the subsequent creation of solid-state cathode/electrolyte interfaces with controlled crystal structures for optimal interfacial properties.
Novel Li-Titanate Anode Thin Film Structures for Li-Garnet All Solid State Batteries
Authors: Pfenninger Reto , Afyon Semih , Garbayo Inigo , Struzik Michal , Rupp Jennifer L. M. 
Published: February 2020

Next generation energy storage devices for stationary as well as mobile electronics will not only need high gravimetric and volumetric capacity, but also long term stability even in rough environments at elevated temperature. Here, all solid state batteries based on Li-garnet structures are shown as interesting model systems that: i.) can partially use industrial waste heat to increase charging times (increased Li+ diffusion) for stationary, ii.) can integrate new high capacity electrode materials which show conventionally a low stability in standard liquid/polymer based Li-batteries, iii.) are easy transferrable to model thin film battery structures for powering of portable electronics. Going all-solid-state opens up completely new pathways for chip integration and downscaling to the sub-micron range for high energy densities to battle supercapacitors. From a materials perspective, cubic garnet Li7La3Zr2O12-based structures are among the fastest conducting solid state electrolytes[1]. Moreover, their inherent compatibility with metallic Lithium, stability in a wide voltage range as well as their Arrhenius-activated conduction mechanism support their prospering interest for all solid state large-scale and future microbatteries. On the electrode side, Li4Ti5O12 is known as one of the most stable anode material due to its remarkably low volume expansion upon lithiation/delithiation and its good cycle performance [2].
We hereby report our latest progress on nanostructuring different promising anode thin films of Li4Ti5O12 / TiO2 mixed-phase deposited by pulsed laser deposition and constructed bilayer half-cells batteries systems with Li7La3Zr2O12 pellets as the electrolyte. Rate capability studies as well as galvanostatic cycling of this system showed promising initial capacity and acted as a case study for the well-known Li4Ti5O12 thin film anode, shown its good compatibility with the investigated solid garnet electrolyte. Near-order phenomena could be tracked by Raman spectroscopy and gave insight into the process of lithiation and delithiation. To the best of our knowledge, no such study has yet been reported in literature. However, degradation and ageing effects still remain challenging and will be discussed.
References

[1] Thangadurai et al., Chemical Society Reviews 43(13), 4714.

[2] Kumantani et al. Applied Physics Letters 101(12), 123103.
Nanostructured Lithium Transition Metal Orthosilicates Made By Flame Spray Pyrolysis
Authors: Wagner Nils P. , Vullum-Bruer Fride , Svensson Ann Mari 
Published: February 2020

The polyanion based materials gained significant interest since the discovery of LiFePO4 as a safer cathode material in 1997 [1], and of Li2FeSiO4as a new Li-battery cathode material in 2005 [2]. Lithium transition metal orthosilicates are promising cathode candidates since they allow Li extraction/insertion beyond one Li-ion per formula unit. Additionally, they consist of cheap, environmentally benign and abundant elements [3]. However, these materials suffer from poor conductivity, ionic as well as electronic, which demands the need for nanostructuring and conductive coatings. And in order for the orthosilicates to be real competitors to current commercial cathode technology, it is vital to find cost efficient and scalable methods for production of nanosized powders.
Here, we present a time-efficient and scalable aerosol combustion method with subsequent annealing, leading to nanoscale and carbon-coated Li2FeSiO4 and Li2Fe0.5Mn0.5SiO4. Using liquid-feed flame spray pyrolysis, we demonstrate synthesis of highly phase pure materials in a relatively short time. The work shows the importance of synthesis parameters such as precursor concentration, and its effect on particle size, degree of agglomeration, and long-term performance. In the case of Li2FeSiO4, the optimised precursor concentration yielded particles of about 30 nm, which delivered an initial discharge capacity of up to 150 mAhg-1 at 60 °C and C/20. Furthermore, over 50% of the capacity is retained at a high rate of 5C, and long-term cycling showed outstanding capacity retention of over 90% after 300 cycles at a moderate rate of C/2. Li2Fe0.5Mn0.5SiO4 on the other hand,was shown to suffer from a severe capacity fade, and upon prolonged cycling the redox activity can be attributed solely to Fe.
[1] Padhi A. K., Nanjundaswamy K. S., Goodenough J. B., J. Electrochem. Soc, 1997, 144, 1188-1194.
[2] Nyten A., Abouimrane A., Armand M., Gustafsson T., Thomas J. O., Electrochemistry Communications, 2005, 7, 156-160.
[3] Saiful Islam M., Dominko R., Masquelier C., Sirisopanaporn C., Armstrong A. R., Bruce P. G., J. Mater. Chem., 2011, 21, 9811-9818
Single Wall Carbon Nanotube-Containing PVA Based Carbon Nanofibers for Lithium Ion Battery Anodes
Authors: Serife Pampal Esra , Stojanovska Elena , Uzun Davut , Kilic Ali 
Published: February 2020

Lithium ion batteries have increasing importance due to the urgent demand for widespread applications in electric/hybrid vehicles, electronic devices, and the grid energy storage. Graphite is one of the most commonly used anode material with low theoretical capacity(372mAh/g) and limited rate capability. In order to improve battery Li-ion storage capacity many researchers have investigated different carbonaceous anode materials with various configurations. Among them, carbon nanofiber is of particular interest for providing high capacity and cycling stability due to its high surface area, porous structure and high electric conductivity which not only shorten the lithium ion path through the electrode but also provide large electrode/electrolyte interface for the charge-transfer reaction properties.
Carbon nanofibers can be directly used as free standing and binder free anodes. There are several nanofiber production methods, among which electrospinning is the most promising due to its simplicity and versatility. Carbon nanofibers can be produced with different precursors such as Pitch, polyacrylonitrile(PAN), polyvinypyrrolidone(PVP), polyvinyl alcohol(PVA) etc. Polyvinyl alcohol is a promising material due to its water soluble and environmentally friendly character.
In this study we report a method to produce free-standing binder free single wall carbon nanotube containing carbon nanofibers as anode for lithium ion battery. Composite nanofibers prepared via electrospinning of single wall carbon nanotubes (SWCNT) dispersed into polyvinyl alcohol solution, followed by iodination at 100°C and heat treatment in an inert atmosphere at 800°C. Carbon nanotubes were added to the polymer solution in different concentrations 0,1% , 1%, and 5 %. An increase of the carbon nanotube concentration in the fibers led to carbonized nanofiber mats with increased electrical conductivity. TGA and Raman analyses showed that carbon nanotubes presence improves the carbon yield of the mats and their handleability. Galvanostatic cycling tests of half cells revealed that addition of carbon nanotubes improves battery capacity. We attribute the capacity increase of the composite nanofibers to the carbon nanotubes structure. Moreover carbon nanotubes increased the handleabilitiy of the mat which is crucial for freestanding, binder free anode materials.
Advanced Silicon-Graphene Anodes for High Performance Applications
Authors: Hayner Cary , Lau Joshua , Ha Seonbaek , McKinney James , Wang Francis P. , Mayekar Samir 
Published: February 2020

Rechargeable batteries with improved energy and power density have many potential, high impact applications including advanced portable electronics and electric vehicles. However, most ‘next-generation’ materials capable of providing improved performance suffer from rapid capacity degradation or severe loss of capacity when rapidly discharged.
Silicon is a promising anode material that is widely investigated as a potential successor for graphite since it can store significantly more energy per mass and volume. Tremendous advancement towards commercialization of silicon anodes – including improving cycle life and minimizing electrode swelling – has been made over the past decade. Proper electrode engineering has brought silicon-based anode materials closer to commercialization into consumer applications. However, cycle life and irreversible capacity losses (ICL) due to side reactions continue to be issues that plague their widespread use. However, silicon technology has not yet been significantly commercialized due to a number of shortcomings.
Graphene, an atomically thin version of graphite widely regarded as a wonder material, has the potential to overcome many of the remaining issues due to graphene’s unique combination of high surface area, high in-plane electrical conductivity, excellent tensile modulus and mechanical durability. In this presentation, we will describe the approaches and architectures employed using silicon-graphene composites to accelerate their development as well as remain challenges to be solved.
SiNode Systems is a battery materials venture developing silicon-graphene anodes for the next generation of lithium-ion batteries. SiNode anodes offer higher battery capacity and faster charging rates, all while being produced via a low cost solution chemistry-based manufacturing process. SiNode seeks to change the landscape for lithium-ion batteries so they can meet the demands of a wide range of industries, from consumer electronics to electric vehicles.
High Energy Lithium Ion Batteries Based on Cobalt Rich Composite Cathode and Silicon Anode
Authors: Kumar Sujeet 
Published: February 2020

Batteries are the main limitation to the wide spread adoption of electric vehicles and plug in hybrids. Battery energy density must be improved to increase EV driving range and lower battery cost. State of the art high energy lithium batteries use NCA cathode and graphite anode e.g. cylindrical 18650 cells that can provide specific energy up to 250 Wh/kg. Replacement of graphite with silicon based anode is mandatory to further boost specific energy. However, cells with silicon based anode have poor cycle life and very high swelling. Proper selection of cathode is also important to attain high energy density when paired with Silicon based anode. Although the capacity of Si-based anode materials are high, their intercalation potential is much higher than that of Li or graphite which translates to a lower overall cell voltage (at least 0.4V lower) resulting in lower energy density. A high capacity and high average voltage cathode is required to compensate the overall drop in the average voltage.
In this work, Cobalt-Rich Composite (CRC) cathode has been developed that also contains significant amount of Nickel and Manganese. The resulting CRC cathode shows stable high voltage performance compared to LCO. Traditionally the structure of LCO cathode degrades at high charge voltages (>4.4V) when >0.5 moles of Li are extracted from the structure. The CRC cathode enables high electrode active content (>97%) and high electrode density (>4.0g/cc), high average voltage (3.95V) and high specific capacity (>190 mAh/g in half cell). Most importantly, CRC cathode does not exhibit any voltage fade upon cycling at higher voltages (>4.45V) as observed in lithium rich manganese rich composite cathode.
CRC cathode has been complemented with a high capacity SiOx-based anode electrode in a high energy cell. Typical commercially available Si-based materials suffer from large volume expansion resulting in pulverization and poor cycle life. We present high capacity SiOx-based anode (>1400 mAh/g) electrodes with high percent active content (>80%) that has shown to cycle over 500 times. A novel anode fabrication approach has been used taking advantage of a high strength binder, carbon nanotube network and pre-lithiation. Swelling, cycling and abuse testing results of the cells will be presented. Figure 3 shows 10Ah capacity pouch cells integrating CRC cathode and SiOx anode with specific energy of ~350Wh/Kg. The cells show excellent rate capability as required for automotive and drone applications. There is significant energy above lower cut off voltage 3.0V required by consumer electronic devices. This presentation will also cover remaining challenges associated with CRC cathode and SiOx anode with respect to synthesis, performance and cell manufacturing.

Figure 1