bluuebunny/crossref_metadata_2025_split huggingface dataset:
(Keynote) Reactions in Lithium Ion Batteries - Focusing on Interfacial Li+ Transfer -
Authors: Ogumi Zempachi 
Published: February 2020

Lithium ion batteries (LIBs) can be defined as

Rechargeable batteries based on rocking-char type reactions of Li+

Batteries are prepared at a discharged state.

In this rocking-chair type batteries, insertion & extraction of Li+play a main role of battery reactions and electron transfer takes place between active materials and current collectors. The reaction seems simple compared with traditional batteries like lead-acid battery but not so simple.
In discharge of LiC6 / LiPF6, EC-DEC / Li1-xCoO2, Li+ inside graphite diffuses to the surface area and jumps out to electrolyte and solvated mostly with EC. The solvated lithium ion diffuses to the interface area between Li1-xCoO2 and electrolyte. Solvated Li+ removes their solvent shell and jump into Li1-xCoO2. The Li+ moves to inner of Li1-xCoO2.
The slowest step determines the reaction rate of the system. Under conditions that diffusion path is short and electronic conduction of the active materials is high and ionic conduction of electrolyte is high, de-solvation process become the slowest step. The activation energy of the step reaches Ca. 60 kJ/mol that depends slightly on electrolyte and is almost independent of host lattice.
Extraction of Li+ from C6Li cause the decrease in valence of carbon (graphene layer) and insertion into Li1-xCoO2 decreases the valence of cobalt forming host lattice. The valence change must cause atomic distance of host lattice, interlayer contraction of graphene forming graphite and elongation of Co-O length, i. e., phase transition must occur in solid phase. No information is available on the rate of this phase transition and we can consider that only oxide and other materials that can change the phase smoothly at the valence change are useful as active materials of lithium ion batteries.

Figure 1
Vanadium and Chromium Molecular Cluster Batteries (MCB): Li- Storage in Transition Metal Complexes
Authors: Rinck Julia , Das Bijoy , Fichtner Maximilian 
Published: February 2020

Increasing energy demands and the requirement to reduce carbon dioxide emissions at the same time accelerated the world-wide research on renewable energy sources and energy storage. However, for future applications in personal electronics, electro-mobility and decentralised energy storage, new LIB electrode materials based on light-weight and earth abundant components with superior redox activity, long-term stability and high energy density are urgently required.
The concept of using molecular transition metal clusters as active electrode materials for reversible Li ion shuttling opens up a new direction for energy storage.[1] These metal complexes are interesting electrode materials due to the ability of the transition metal ions to exist in several oxidation states and reversibly reacting with Li.[2,3]

In this study we introduce LIBs based on molecular cluster systems of the early transition metal ions vanadium and chromium as the cathode active material, in a so-called molecular cluster battery (MCB).
Transition metal complexes of different ligand systems were characterised by IR, XRD and SEM techniques. Their Li cycling behaviour was investigated by galvanostatic cycling and cyclic voltammetry (CV). High reversible specific capacities with low capacity loss were found and multi-step redox processes were observed reflecting the various oxidation states of these metal ions. The 2D channels of the crystalline compounds, which are revealed in their crystal packing diagram, are suitable for an easy Li ion transportation trough the structure. The Li ion diffusion coefficients were determined by various electrochemical techniques, such as GITT, CV and EIS to understand the Li ion kinetics of these molecular metal clusters.
The various oxidation steps of molecular cluster compounds allow multi-step redox changes making these materials interesting compounds with potentially high specific capacities and allow a study of the kinetics of the lithium ion diffusion pathway.
References:
[1] H. Yoshikawa, C. Kazama, K. Awaga, M. Satoh, J. Wada, Chem. Commun. 2007, 3169-3170.
[2] H. Wang, Z. Zeng, N. Kawasaki, H. Eckert, H. Yoshikawa, K. Awaga, Chemistry, 2013, 19, 34, 11235-40.
[3] H. Yoshikawa, S. Hamanaka, Y. Miyoshi, Y. Kondo, S. Shigematsu, N. Akutagawa, M. Sato, T. Yokoyama, K. Awaga, Inorg. Chem., 2009, 48, 19, 9057-9059.
A High-Voltage and High-Capacity Li1+XNi0.5Mn1.5O4.0 (0 < x < 1) Cathode Material: From Synthesis to Full Lithium-Ion Cells
Authors: Mancini Marilena , Axmann Peter , Gabrielli Giulio , Kinyanjui Michael Kiarie , Kaiser Ute , Wohlfahrt-Mehrens Margret 
Published: February 2020

Improvements of currently available LiB technology are needed to meet the requirements for automotive applications especially in terms of energy density. In the current Li-ion battery technology, the cathode active material represents the main limiting factor for reaching higher values of energy density. Therefore, cathode materials with either increased specific capacity or increased working potential with respect to the currently used active materials are necessary to improve energy density. Moreover, increased safety and reduced cost are needed for large scale applications. The substitution of Co in the cathode structure with more accessible elements is the key for the cost reduction.
In this communication, we describe a series of Co-free, Li-rich Li1+xNi0.5Mn1.5O4.0 (0<x<1) compounds obtained via a low-temperature synthetic method. Morphological, structural and electrochemical characterization will be discussed. The lithium‐nickel‐manganese oxide compounds were tailored with respect to morphology, particle size and shape distribution for facile processability during electrode development. The specific particle architecture, consisting of densely packed nano‐sized primary crystallites, allows reaching a tap‐density of 2.4 g cm-3. In the potential range 2.4-4.9 V, the cathode material of composition Li1.5Ni0.5Mn1.5O4 shows a specific capacity of 210 mA h g-1, very good cycling stability and low voltage hysteresis in half-cells vs. lithium.
In addition, we demonstrate for the first time the high-voltage and high-capacity cathode application in full Li-ion cells versus graphite anode with very high cycling stability. The initial Li content can be tailored in order to be used for compensating the irreversible capacity loss of the graphite anode in full-cells.
The electrochemical mechanism in the low-potential region and the involved phase transitions, studied by different techniques including HR-TEM and XRD, will be discussed together with the electrochemical behavior under different operative conditions.
The good electrochemical performance and low cost, together with the feasibility of a chemical method to obtain Li-rich Li1+xNi0.5Mn1.5O4(0<x<1), make practical applications for high-energy density LiBs possible.
Acknowledgements
This work was supported by the German Federal Ministry of Education and Research (BMBF) in the project Li-EcoSafe (03X4636A).
References
[1] S.-H. Park, S.-W. Oh, C.-S. Yoon, S.-T. Myung, Y.-K. Sun, Electrochem. Solid-State Lett. 8 (3) (2005) A163
[2] S.-H. Park, S.-H. Kang, C.S. Johnson, K. Amine, M.M. Thackeray, Electrochem. Comm., 9 (2007) 262
[3] G. Gabrielli, P. Axmann, M. Wholfahrt-Mehrens, J. Electrochem. Soc. 163 (2016) A470
[4] P. Axmann, G. Gabrielli, M. Wohlfahrt-Mehrens, J. Power Sources 301 (2016) 151
[5] M. Mancini, P. Axmann, G. Gabrielli, M. Kinyanjui, U. Kaiser, M. Wohlfahrt-Mehrens, CheSusChem, submitted

Figure 1
High-Voltage Lithium Metal Phospho-Olivines for Li-Ion Batteries
Authors: Allen Jan L. , Allen Joshua L. , Delp Samuel A. , Wolfenstine Jeff , Jow T. Richard 
Published: February 2020

There is an ever-growing need for higher energy Li-ion batteries. Lithium metal phospho-olivines based on LiCoPO4 are promising cathode materials to help fulfill this need owing to their relatively high discharge capacity of up to 167 mAh g-1 at a discharge potential of 4.8V [1]. However, LiCoPO4 based Li-ion cells show a severe loss of discharge capacity upon multiple charge – discharge cycles owing to structure deterioration and electrolyte decomposition [2]. Partial substitution of Co by Fe significantly improves the cycle life [3] and increases Li+ ion and electrical transport [4]. Our most recent studies show that multi-element substitution for Co in LiCoPO4 further reduces capacity fade, substantially improves discharge capacity and reduces reactivity of the cathode with the electrolyte. Currently, we have achieved an energy storage capacity of 670 Wh kg-1 of cathode material (84% of LiCoPO4 theoretical) which can be compared to a maximum theoretical 576 Wh kg-1 for commercialized LiFePO4. The capacity fade of Li / LiCo1-xMxPO4 half cells over 500 cycles is less than 6%. This paper will report on our most recent results. We will discuss synthesis methods, transport measurements, electronic structure[5], the most promising substitutional chemistry and the structure of substituted LiCoPO4 as well as performance enhancements that result from improving the electrolyte high voltage stability [6].
References

K. Amine, H. Yasuda, M. Yamachi, “Olivine LiCoPO4 as 4.8 V electrode material for lithium batteries,” Electrochem. and Solid State Letters, 3 (2000) 178.

J. Wolfenstine, U. Lee, B. Poese, J.L. Allen, “Effect of oxygen partial pressure on the discharge capacity of LiCoPO4,” J. Power Sources
144 (2005) 226.

J.L. Allen, T.R. Jow, J. Wolfenstine, “Improved cycle life of Fe-substituted LiCoPO4,” J. Power Sources
196 (2011) 8656.

J.L. Allen, T. Thompson, J. Sakamoto, C.R. Becker, T.R. Jow, J. Wolfenstine, “Transport Properties of LiCoPO4 and Fe-substituted LiCoPO4,” J. Power Sources
254 (2014) 204.

M.D. Johannes, K. Hoang, J.L. Allen, K. Gaskell, “Hole polaron formation and migration in olivine phosphate materials,” Phys. Rev. B 85 (2012) 115106.

J.L. Allen, J.L. Allen, S.A. Delp, T.R. Jow, “Electrolyte additives for reducing the irreversible capacity loss, impedance and polarization of a doped LiCoPO4 cathode,” ECS Transactions
66 (2015) 149.

Figure 1
Li Storage in Olivine Structure LiFexMn1-XPO4
Authors: Xia Yong-Yao , Wang Ke 
Published: February 2020

LiMnPO4 shows higher specific energy than that of LiFePO4, but suffers from poor kinetics. The mixed-cation olivine material LiFexMn(1-x)PO4 combined the good rate capability of LiFePO4 and high potential of LiMnPO4. Commonly, LiFe0.5Mn0.5PO4 is considered to exhibit two pairs of plateau in charge-discharge curves associated with MnPO4/LiMnPO4 and FePO4/LiFePO4 phase transformation. We prepared carbon coated LiFe0.5Mn0.5PO4 solid solution material by solvothermal method. This material delivers typical two plateaus in charge/discharge curves at low current rate, but a third plateau appears only during discharge at relative high current rate. The discharge capacity in the addition medium plateau increases with the current rate increases. LiFe0.5Mn0.5PO4 discharge mainly proceeds via the medium plateau at high current rate. Electrochemical measurements demonstrate that the additional discharge plateau can still be attributed to Mn3+ reduction, but with a different mechanism than in pure LiMnPO4 due to the presence of Fe in LiMnPO4 framework that gives the conditions for better kinetics.
Also the battery performance of a full battery consisting of LiFe0.2Mn0.8PO4 and layered transition-metal oxides (NMC) composite cathode and graphite anode was extensively studied. The addition of LMP in NMC greatly improved the battery safety.
Novel Method of Contrast Improvement Applied to Lithium Ion Battery Electrode Materials Enabling Multi Modal and High Resolution 3D Imaging and Advanced Quantification
Authors: Biton Moshiel , Yufit Vladimir , Tariq Farid , Kishimoto Masashi , Brandon Nigel P. 
Published: February 2020

The authors present for the first time a new methodology of contrast enhancement for multi modal 3D imaging, including novel advanced quantification, on a commercial Lithium Iron Phosphate (LFP) LiFePO4 cathode. The aim of this work is to improve the quality of the 3D imaging of challenging battery materials by developing methods to increase contrast between otherwise previously poorly differentiated phases. This is necessary to enable capture of the real geometry of electrode microstructures, which allows measurement of a wide range of microstructural properties such as pore/particle size distributions, surface area, tortuosity and porosity. These properties play vital roles in determining the performance of battery electrodes. In this study we present a novel method of sample preparation with a new type of epoxy impregnation, brominated (Br) epoxy, which is introduced here for the first time for this purpose and found suitable for multi modal imaging, for both focused ion beam scanning electron microscope (FIB-SEM) tomography and X-ray micro tomography. The Br epoxy improves image contrast, which enables higher FIB-SEM resolution (3D imaging), which is amongst the highest ever reported for composite LFP cathodes using FIB-SEM. In turn it means that the particles are well defined and the size distribution of each phase can be analysed accurately from the complex 3D electrode microstructure using advanced quantification algorithms.

Figure 1: High resolution 3D image of (a) LFP particle size distribution (b) Carbon particle size distribution (each colour represent a different particle size)

Figure 1
Electrochemical Performance of Carbon-Coated Cauliflower-like WO3 for Li-Ion Batteries
Authors: Kammari Sasidharachari , Yoon Sukeun 
Published: February 2020

Metal oxides have been considered and investigated as alternative anodes for use in lithium ion batteries. The research focus is on two different mechanism groups: intercalation–deintercalation reaction and conversion (redox) reaction. The intercalation–deintercalation mechanism is that transition metal oxides and other compounds with a multidimensional layer structure can reversibly intercalate lithium ions into the lattice without destroying their crystal structure. While conversion mechanism usually produces metallic nanoparticles embedded in an insulating Li2O matrix and the shows generally much higher theoretical capacity than that of already-commercialized graphite.
Among the metal oxides, tungsten oxides (WO2, WO3, and WO3-x
H2O) as one of the important metal oxides with respect to physicochemical properties, have been extensively investigated for such applications as gas sensors, photocatalysis, electrochromic devices, electronic devices, dye-sensitized solar cells, supercapacitors, and lithium ion batteries. Interestingly, the tungsten oxides have better electronic conductivity (10–10-6 S cm-1) than some of the other oxides; in addition, they also rely on designing a nanostructured particle with a small radius and right crystalline phase for fast lithium-ion insertion and superior electrochemical performance. From this point of view, a wide variety of approaches have been pursued over the years for the synthesis of tungsten oxides, such as nanoparticles, nanowires, nanorods, and nanoflowers using various approaches which include a hydrothermal reaction, combustion process, sol–gel process, solution-phase reaction, template directed method, mechanochemical activation, and hot-wire chemical vapor deposition (HWCVD) method. However, most of the previous approaches led to the formation of monoclinic W18O49, hexagonal WO3, and WO3-xH2O nanostructures. There have been very few studies on nanostructured monoclinic WO3 (m-WO3).
In this study, we will present a facile hydrothermal process that obtains cauliflower-like carbon-coated WO3 oxide with a high rate-capability and good cycling performance for lithium-ion batteries. The motivation in this study is to explore the possibility of using m-WO3 as an anode material for lithium-ion batteries and to elucidate its reaction mechanism with lithium during the charge–discharge process.
Probing the Interfacial Parasitic Reactions Kinetics in Lithium-Ion Battery
Authors: Zeng Xiaoqiao , Chen Zonghai , Amine Khalil 
Published: February 2020

The global R&D effort has been driven by the growing application of high energy-density lithium-ion batteries to electrify the transportation system and achieve significant reduction on non-renewable fuels consumption and greenhouse gas emission. However, high initial energy-density is still generally obtained with the price of a reduction on battery safety and life, which are fundamentally connected to the parasitic reactions in the cell at various temperatures. The practical high energy-density lithium-ion chemistry needs to be carefully balanced between energy-density and safety/lifetime of the chosen chemistry. The electrochemical validation of the effectiveness of those approaches for improving battery life is practically trivial, but extremely time-consuming, especially for those chemistries that have already been demonstrated capable of being charged/discharged for more than thousand cycles. Therefore, the fundamental understanding/measurement of parasitic reactions not only helps to select a proper life improving strategy, but also substantially shortens the lengthy electrochemical validating process.
In this work, a home-built high-precision leakage current measuring system was deployed to investigate the parasitic reaction kinetics between lithium transition metal oxide cathode (LiNi0.6Mn0.2Co0.2O2) and conventional carbonate electrolyte (1.0 M LiPF6 EC/EMC 3:7). The working electrode was held at a specific potential using the source meter, presuming that the state of the charge or the lithium concentration in the working electrode will reach an equilibrium state after the constant-voltage charge/discharge. During this process, the electron obtained from the environment by oxidizing the solvent, will be electrochemically monitored by the external circuit. The kinetic study revealed a strong dependence of parasitic reactions on the practical upper cutoff potential in terms of both the reaction mechanism and the reaction rate. The kinetic data also indicated a significant change of reaction mode at ~4.5 V vs. Li+/Li. The study implies that a different strategy might be needed for effective mitigation of the parasitic reactions for materials targeted for operation at a potential higher than 4.5 V vs. Li+/Li. It demonstrated that the kinetic study could be crucial in developing advanced electrode materials with a fundamental balance between energy density and battery life.

Figure 1
Biogenous Iron Oxide(BIOX)-As a High-Capacity Anode Material for Lithium Ion Batteries
Authors: Furusawa Homare , Takeda Yasuo , Imanishi Nobuyuki , Takada Jun 
Published: February 2020

1.Introduction
Biogenous iron oxide(BIOX) is produced by Leptothrix ochracea, aquatic bacteria living in the world. BIOX is amorphous Fe3+-based oxide containing Si and P, and takes tube-formed structure. In recent years, lithium-ion batteries have been widely used and intensively studied to meet an increasing variety of application in the future. Especially exploitation of high-capacity lithium-ion batteries is very important. The capacity of BIOX is approximately three times larger than that of graphite, so that BIOX is expected as a new high-capacity anode material for lithium ion batteries. BIOX belongs to the category of conversion anode materials and shows superior cycle and rate performance beyond normal conversion anode; however, the large first irreversible capacity remains in disadvantage for the practical use. In this study, we applied lithium pre-doping to BIOX electrode to eliminate the first irreversible capacity, and succeeded to provide the lithium ion battery with high capacity and high cycle performance.<
2.Experimental
The BIOX cultured in Okayama university was firstly mixed with CNF (Carbon nanofiber) as a conductive agent, SBR (styrene-butadiene rubber) / CMC (carboxymethyl acid) as a binder (80:10:10 wt%) and water as a viscosity adjustor in an agate mortar. The slurry was coated on a copper foil, dried in air at 80ºC and vacuum-dried at 120ºC for 3h. The punched out electrode was pressed under the pressure of 2t.
The first irreversible capacity was eliminated by contacting a lithium metal sheet to the electrode in an electrolyte (LiPF6in EC / DEC (1:1)). The charge-discharge behavior was measured in a coin type cell (2025) with Li metal as a counter electrode. The current rate was 0.1 C (the theoretical capacity of BIOX: 666mAh / g) and the voltage range was set between 50 and 3000mV
3.Results
Figure 1 shows the voltage profiles of the first cycle for the as-prepared and Li- contacted electrodes. The former showed the first discharge capacity of 984mAh/g, and the following charged one of 712mAh/g. The first irreversible capacity is considerably large; the coulomb efficiency is only 72.0%. After the second cycle, almost 100% efficiency was obtained. On the other hand, the Li pre-doping by the contact of Li metal brought the high coulomb efficiency. The electrode of 30 s contacting of Li metal showed discharged capacity of 972mAh/g and charged one of 818mAh/g(coulomb efficiency:84.1% ).
The first irreversible capacity due to the SEI formation on the nano-particles in BIOX may be compensable with the reaction of Li metal in advance.

Figure 1
Electrochemical Performance of Graphite-Silicon Alloy Composite Anodes Using Cross-Linked Poly(vinyl alcohol) Binder for Lithium-Ion Batteries
Authors: Yook Seung Hyun , Kim Sang-Hyung , Kim Dong-Won , Kim Seon-Kyong , Park Cheol-Ho 
Published: February 2020

The growing demand for rechargeable batteries requires a great improvement in the energy density of current lithium-ion batteries. In order to increase the energy density of lithium-ion batteries, silicon anode materials have been actively studied, because they exhibit a high theoretical capacity, a low reduction potential, are environmentally benign and are low cost.1 However, they suffer from substantial volume changes during cycling, which are highly detrimental to the cycling stability of lithium-ion batteries. The mechanical stresses caused by repeated volume changes can fracture the electrode, which results in poor electrical contacts between the active materials, electronic conductors and current collector. To solve these problems, many studies have been carried out by different approaches such as controlling the particle size and morphology, alloying with inert metals, embedding silicon in a conductive material, and applying several functional binders. In order to obtain the silicon-based composite anodes with high capacity and good cycling stability, we synthesized silicon alloy that was composed of silicon nanoparticles embedded in Al-Fe-Ti-Ni matrix phases. Using these silicon alloy material, we prepared the composite electrodes composed of graphite powder and silicon alloy particles. In these composite anodes, poly(vinyl alcohol) (PVA)s with different degree of cross-linking were employed as polymer binders. The effect of degree of cross-linking on interfacial adhesion and cycling performance of the composite electrodes was investigated to identify optimum processing condition. A systematic study demonstrated that the appropriate cross-linking of PVA made the electrodes mechanically strong and remarkably improved the cycling stability of the electrodes.

References

1. B. Liang, Y. Liu and Y. Xu, J. Power Sources, 267, 469–490 (2014).