bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Novel Intercalation Cathode Material with 1.7 Li per Transition Metal
Authors: Chen Ruiyong , Ren Shuhua , Cambaz Musa Ali , Hahn Horst , Fichtner Maximilian 
Published: February 2020

Vanadium-based materials have received considerable attention for lithium ion batteries due to the facts that vanadium is the fifth most abundant transition metal in the earth’s crust, its relatively low atomic mass, its multiple oxidation states. The redox operating voltage (typically < 4.5 V) of vanadium-based materials is typically within the stability limit of conventional electrolyte, and vanadium oxides have rich crystal structures [1]. The ability of layered V2O5 for Li+ insertion has been well characterized. Intercalation of one Li+ per formula unit corresponds to a specific capacity of 147 mAh g-1. Further Li+ ions (x > 1 in Li
x
V2O5) insertion may cause irreversible structural transformations [2].
In this work, a new high-capacity (> 400 mAh g-1) and high energy density (> 1000 Wh kg-1) cathode material comprising of lithium metal oxyfluoride with a representative composition of Li2VO2F has been synthesized through a mechanical ball-milling method. In comparison with the prior art, several remarkable features of this new compound Li2VO2F are (i) two-electron reaction based on V3+/V5+ is accessible per transition metal, (ii) the initial composition is at lithiated state, (iii) it has a high theoretical specific capacity of 462 mAh g-1. Furthermore, in comparison with the start-of-the-art commercial cathode materials, this new material offers the opportunity to reach higher capacity and energy density.
References:
[1] N. A. Chernova, M. Roppolo, A. C. Dillon, M. S. Whittingham, J. Mater. Chem. 2009, 19, 2526
[2] C. Delmas, H. Cognac-Auradou, J. M. Cocciantelli, M. Ménétrier, J. P. Doumerc, Solid State Ion. 1994, 69, 257.
On the Oxidation State of Manganese in Li-Ion Cells: A New Perspective
Authors: Halalay Ion C. , Ziegelbauer Joseph M. , Li Zicheng 
Published: February 2020

It has been long recognized that dissolution of transition metals, particularly Mn, at the positive electrode is the starting point for a major performance degradation mechanism in Li-ion batteries (LIBs).1-4 We present recent X-ray absorption spectroscopy data on components from LixMn2O4 spinel – graphite (LMO-GR) cells with 1M LiPF6in an ethylene carbonate : diethyl carbonate (1:2 v/v) electrolyte, after 20 days of cycling at 50 °C with 100% depth of discharge and C/5 rate.
Results from the Mn K edge (6539 eV) XANES analysis indicate average oxidation states near +3 for Mn cations in the graphite electrodes and separators from cells that were subjected to a 48 hour stand (in either discharged or charged state) subsequent to the high-temperature galvanostatic cycling, see Fig. 1. This suggests that Mn metal or in oxidation state +2 can only be minor fractions of the Mn existing outside the positive electrode of a Li-ion battery. Our results run counter to the prevailing view that Mn2+ cations arising from a disproportionation reaction of two Mn3+cations at the positive electrode, followed by dissolution into and migration through the electrolyte, and ending with deposition at the negative electrode, are widely responsible for the performance degradation observed in graphite-LMO LIBs. We will discuss the possible sources of discrepancy between our results and previously published data, as well as the implications of our results for measures to mitigate the Mn dissolution related LIB performance degradation mechanism, see Fig. 2.

References

1. D. H. Jang, & S. M. Oh, J. Electrochem. Soc.
144, 3342 (1997).
2. Y. Xia, Y. Zhou, & M. Yoshio, J. Electrochem. Soc.144, 2593 (1997).
3. G. Amatucci, C. N. Schmuts, A. Blyr, C. Sigala, A. S. Gozdz, D. Larcher, & J.-M. Tarascon, J. Power Sources
69, 11 (1997).
4. N. Kumagai, S. Komaba, Y. Kataoka, & M. Koyanagi, Chem. Lett.1154 (2000).

Acknowledgements

Use of the National Synchrotron Light Source, Brookhaven National Laboratory, was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-98CH10886. Use of the Advanced Photon Source, an Office of Science User Facility operated for the U.S. Department of Energy (DOE) Office of Science by Argonne National Laboratory, was supported by the U.S. DOE under Contract No. DE-AC02-06CH11357.
Influence of Convective Drying Parameters on Electrode Performance and Physical Electrode Properties
Authors: Westphal Bastian , Bockholt Henrike , Kwade Arno 
Published: February 2020

As the need for nonpolluting individual mobility is rising, the production processes of lithium-ion batteries are gaining more and more attention. Although a lot of research for new battery materials or even for alternative battery technologies is done, the state of the art production process for large scale automotive lithium-ion batteries is still not completely understood. To get as close as possible to the theoretical performances of the used materials, an optimized process which includes a deep understanding of its influences on electrode structure and in the end on cell performance is essential. For this reason the drying process as one of the key-process-steps in the electrode production process is examined.
Since drying fixes the coating structure by evaporation of the solvent, the sedimentation of active material particles and the formation of the binder and carbon black matrix is influenced in a crucial way. In the present work some of the various drying parameters such as air temperature, outlet speed, air flow rate and residence time are varied and their influence on electrode structure is examined. A pilot-plant continuous convective dryer with three individual adjustable segments and a total length of six meters is basis of these investigations.
In order to analyze the resulting electrode structure measurements like mercury porosimetry (to determine the porediameter distribution of the coating), electrode conductivity (to describe the network of the conductive additives) and adhesion force measurements (to characterize the binder distribution) were carried out. As an example, a strong impact on the coating’s adhesion force to the current collector with increasing drying intensity (or faster solvent evaporation, respectively) and coating thickness could be found and explained by changes in electrode’s structure. Deeper insights in the processes affecting electrode structure can be obtained by determination of the electrochemical cell performance, thus allowing the establishment of process-structure-property relations.
Besides offline measurements to determine the electrode structure the drying process itself is monitored online by detecting the shift from constant rate drying period to falling rate period via infrared temperature sensors which measure the surface temperature of the coating. If the coating speed is kept constant the point of drying period change can be detected within a shorter distance from the dryer inlet when the air temperature is increased (see Fig. 1). The period change is identified for different drying parameters and electrode thicknesses as thicker electrodes tend to show a more distinct influence by the drying process.
In summary recent investigations show that electrode properties (e.g. adhesion force) resulting from solvent evaporation and structure fixation are clearly dependent on drying parameters and thus enabling a way for enhancing the battery’s performance.
Performances and Ageing Mechanisms of LiMn1-XFexPO4 // Graphite Prototype Cells
Authors: Dumont Erwan , Castaing Frédéric , Tessier Cécile 
Published: February 2020

Olivine C-LiFePO4 has been intensively studied since 1997
[1
] due to its high thermal stability and the expected material cost reduction compared to usual cobalt based oxides. However, the energy density loss induced by the low operating voltage of LiFePO4, 3.45V, leads to consider LiMnPO4, 4.0V, as a promising candidate. But without dopants this material is kinetically limited: iron substitution seems to be a solution to make its utilization possible.
Several publications[2
]
,
[3
]
,
[4
]
present promising results on this type of material with good rate capabilities, good cycle life, but these results are mainly obtained in half cells vs Li° with low loaded electrodes.
Our work is focused on C-LiMn2/3Fe1/3PO4which has shown an excellent cyclability in half cells vs Li°.
Prototype cells vs graphite have been assembled using high loaded electrodes, with a design close to industrial cells. Results obtained show:
- excellent rate capability: >90% of capacity is recovered at 5C
- excellent cycle life: 80% of capacity is still remaining after 900 cycles
The study of ageing mechanisms by post-mortem analyses will be discussed.
Acknowledgment: All results presented here have been obtained on a material supplied by Clariant
[1] A. K. Padhi, K. S. Nanjundaswamy and J. B. Goodenough, Journal of The Electrochemical Society 1997, 144, 1188-1194.
[2] S.-M. Oh, H.-G. Jung, C. S. Yoon, S.-T. Myung, Z. Chen, K. Amine and Y.-K. Sun, Journal of Power Sources 2011, 196, 6924-6928.
[3] B. Z. Li, Y. Wang, L. Xue, X. P. Li and W. S. Li, Journal of Power Sources 2013.
[4] L. Hu, B. Qiu, Y. Xia, Z. Qin, L. Qin, X. Zhou and Z. Liu, Journal of Power Sources 2014, 248, 246-252.
Effects of Heat Treatment Temperature on the Electrochemical Performance of LiV3O8 Obtained By Solid-State Method
Authors: Bae Ki Yoon , Yoon Woo Young 
Published: February 2020

The LiV3O8 compounds were synthesized by Solid-state method and calcination at different temperature (with heat treatment temperature ranging from 300 °C ∼ 600 °C) in order to find the relationship between heating temperature and electrochemical properties of LiV3O8.
The effects of precursor and heat treatment conditions on the structure, morphology, and electrochemical properties of the LiV3O8 were investigated by the implementation of X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), transmission electron microscope (TEM), and energy dispersive spectroscopy (EDS). In order to find proper heat treatment temperature, TGA/DSC was performed too. All cells were cycled 50 times at a C-rate of 0.2 with the cut-off voltage ranging from 1.8 to 4.0V (versus Li/Li+). The result was analyzed by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV).
As the heat treatment temperature is increased, LiV3O8 has better crystalline phase but its primary particle size is grown bigger. For the sake of better electrochemical performances, especially high capacity retention, LiV3O8should have a proper size and size distribution.
[1] J. Feng, X. Liu, X. X. Zhang, J.Jiang, Z. Zhao, and M. Wang, J. Electrochem. Soc,
156, A768 (2009)
[2] H. Yang, J. Li, X.G. Zhang, Y.L. Jin, J. Mat. pro. tec, 207, 265 (2008)
[3] D. Wang, L. Cao, J. Huang, J. Wu, Ceram. Int, 38, 2647, (2012)
[4] Y.Q. Qiao, J.P. Tu, X.L. Wang, J. Zhang, Y.X. Yu, and C.D. Gu, J. Phys. Chem, 115, 25508 (2011)
Single Step Aerosol Route Synthesis of Mixed Oxide Nanostructures for Useas Additive Free Lithium Ion Battery Electrodes
Authors: Chadha Tandeep Singh , Fang Jiaxi , Biswas Pratim 
Published: February 2020

Lithium titanate has been successfully used as anode for lithium ion batteries due to its high rate capability, enhanced structural stability and safety, making it suitable for application in electric vehicles (EV) and hybrid electric vehicles (HEV). Current synthesis methods involve multiple steps including the production a nanoparticle powder, followed by coating the powder onto a conductive substrate along with conductive additives and binding agents and finally annealing. These processes do not offer sufficient control over the morphology, crystallinity and orientation of the active material. A single step process for the synthesis of nanostructured thin films directly on the current collector would facilitate the fabrication of nanostructured anodes without the use of any binding agent.
The aerosol chemical vapor deposition (ACVD) process is a single step, low cost method for the synthesis of nanostructured thin films. ACVD has been successfully demonstrated for the synthesis of metal oxides such as TiO2 and NiO and for mixed oxides of Al2TiO5. The process involves decomposition of a metal organic precursor in the reactor to yield metal oxide molecules which grow by homogenous nucleation to yield particles. These particles deposit onto a heated substrate where they sinter to form thin films of different morphologies. The synthesis of mixed oxide thin films involves heterogeneous nucleation of multi-component metal oxides to yield mixed oxide particles. The process allows for the synthesis of different nanostructures with varying morphologies, which include dense, single crystal columnar, granular and branched morphologies, through control over various process parameters.
This work focuses on controlling the composition and morphology of lithium titanate thin films synthesized by the ACVD process. Control over the characteristic times and the reaction rates was used to control the morphology and the stoichiometry of the synthesized thin films. The surface morphology of the films was characterized by scanning electron microscopy and the crystal structure was examined by x-ray diffraction analysis. X-ray photoelectron spectroscopy was used to probe the chemical composition of the films. Electrochemical characterization of the synthesized nanostructured anodes was performed in half cell configurations vs Li/Li+. The effect of stoichiometry and composition of the film on the electrochemical performance will be presented.
Development of Novel Fe2O3-Al2O3 Solid Solution Electrode by Using Mechanochemical Synthesis
Authors: Sawada Eisuke , Takemoto Masahi , Harada Jumpei , Takai Shigeomi , Yao Takeshi 
Published: February 2020

Introduction

α-Fe2O3 is expected to perform as a favorable electrode material for lithium ion battery due to low cost and low toxicity. The cathode reaction is Fe2O3+6Li++6e-→2Fe+3Li2O. It is considered that Fe site in crystal structure of α-Fe2O3 is lost during cathode reaction, and then the specific capacity declines drastically.
When crystal structure of α-Fe2O3 is held, cyclic performance will be enhanced. In this study, we synthesized Fe2O3-Al2O3 solid solution in various molar ratios by mechanochemical synthesis. We investigated cyclic performance of the solid solution for the electrode of lithium ion battery.

Experiment

γ-Fe2O3 and γ-Al2O3 were mixed in molar ratios of Fe:Al=(1-x):x (x=0.05, 0.33, 0.40, 0.45, 0.50, 0.60, 0.65, 0.67, 0.95) by theta composer (Tokuju corp.), then synthesized Fe2O3-Al2O3 solid solution by mechanochemical synthesis with ball mill (Premium line, Fritsch GmbH). X-ray diffraction analysis of the obtained sample was conducted using Ultima IV (Rigaku co.) (CuKα, 40kV, 40mA).
The electrode was fabricated by mixing powder of the solid solution as the active material, acetylene black as a conducting additive and PTFE as a binder at the ratio of 60:40:3 by weight. C。opper mesh was used as current collector. Metal lithium was used as counter electrode and reference. The electrolyte was an 1M LiPF6 EC:EMC (3:7 v/v%).
We discharged the electrode material to the cutoff voltage of 0.1V (vs.Li/Li+) at 0.1A/g and charged to the cutoff voltage of 3.5V (vs.Li/Li+) at 0.1A/g. We measured cyclic performance of the solid solution.

Result and Discussion

We measured X-ray diffraction (XRD) of the samples synthesized with ball mill in various molar ratios from 20 degrees to 80 degrees in 2θ. We obtained lattice constants precisely by fitting the XRD peaks with Lorentz function. Unit cell volume is calculated from the lattice constants. For every molar ratio, the lattice constants and the unit cell volume are almost equal to those calculated from the lattice constants of α-Al2O3 and α-Fe2O3 (JCPDS database) by using Vegard’s law. It is confirmed that the all samples obtained by this mechanochemical synthesis were solid solutions. It is considered that this is the first report of the synthesis of complete solid solutions of α-Fe2O3 and α-Al2O3.
Fig.1 shows an example of charge-discharge curves of the solid solution (Fe0.6Al0.4)2O3. It shows that 1.4V plateau of the discharge curve is getting to ambiguous as number of cycles increases. Fig.2 shows cyclic performance of the solid solution (Fe0.6Al0.4)2O3. It shows that the specific capacity did not decline even after 300 cycles. It is indicated that the obtained solid solution (Fe0.6Al0.4)2O3 has excellent cyclic performance. It seems that α-Al2O3 solved in α-Fe2O3 keeps crystal structure of the active material.

References

T. Yao, S. Esaki, M. Nishijima, T. Yoshie, S. Park, M. Oda and J. Harada, PCT/JP2012/ 83694
Fabrication of Li4Ti5O12 Spinel Thin Films for Li Mirobattery Applications
Authors: Fung Kuan-Zong , Tsai Shu-Yi , Ni Chung-Ta , Orliukas Antanas F. , Bajars Gunars , Chen Mei-Han 
Published: February 2020

Lithium titanium oxide spinel Li4Ti5O12 has been reported to be a zero-strain lithium insertion host material because it exhibits extremely small variations of the lattice parameters during the charge and discharge processes. In general, Poor adhesion between thin-film electrode and substrates is the common cause for performance degradation of thin-film electrode during repeated charge/discharge tests. Thus, Li4Ti5O12 spinel may be the ideal candidate for the anode of thin-film Li ion battery for long cycle applications.
However, different electrochemical behaviors will be expected when Li4Ti5O12 spinel is prepared in thin-film compared to that in power forms. Therefore, the objective of this work is (1) to fabricate thin film of Li4Ti5O12 spinel by using RF-sputtering technique, (2) to investigate the effect of annealing temperature/atmospheres on the electrical/electrochemical properties of thin film Li4Ti5O12, (3) to evaluate the feasibility of using thin film of Li4Ti5O12 as anode for Li microbattery applications.
In this study, the Li4Ti5O12 thin film was deposited on either the Si substrate or glass substrate by sputtering technique. The crystallization of deposited Li4Ti5O12 thin film will be enhanced by annealing at various atmospheres and temperatures. The single phase Li4Ti5O12 was finally obtained after co-sputtering of Li-containg and Ti-containing targets. The crystal structure and crystallization will be examined by glancing XRD. The resistivity of Li4Ti5O12 thin film will be evaluated by four probe technique and our novel micromeaurement system. The capacity of Li4Ti5O12 thin film will be evaluated from charge/discharge tests.
Improving Electrochemical Performance of Cusi Thin Film By Depositing Cu Thin Film Via Magnetron Sputtering
Authors: Polat Deniz Billur , Eryilmaz Levent , Keleş Özgül 
Published: February 2020

Huge volumetric change occurs in Si anode material during lithiation process results in pulverization or delamination of the thin film from the current collectors, which eventually brings a short cycle life. Previously the use of CuSi as anode material to overcome this problem has been proposed. The results seem promising, even though more improvement has still been required for commercial applications. In this study, we present a strategy to improve the cycle performance of CuSi thin film: depositing a very thin Cu layer on top of the CuSi film. It is believed that Cu presence would improve the electrochemical performance of the anode due to its ductile and electrical conductive behavior.
In this sense, we produced two CuSi films by a magnetron sputtering method. To compare the effect of compliant layer presence on the anode performance, 10nm of Cu film was deposited on the top of the one CuSi film. The electrochemical performance proves that the coulombic efficiency as well as the cycle life of the CuSi film was increased due to the compliant layer existence.
Influence of Doping, Surface Area, and Porosity of Nanostructure Electrodes in Lithium-Ion Batteries
Authors: Stuve Eric M. , Cao Guozhong 
Published: February 2020

Lithium-ion batteries store electrical energy in the form of chemical potential, the same as that in primary batteries; however, the charge-discharge process in lithium-ion batteries is more complex as it involves not only Faradaic reactions at the interface between electrode and electrolyte, but also mass and charge transport and volume change of electrodes that commonly possess low electrical conductivity. One strategy for improving battery performance is the use electrodes away from thermodynamic equilibrium. These include nanostructures with high surface energy, poor-crystalline materials, and materials with significant surface or bulk defects. Such materials are in a higher energy state and more readily undergo phase transformation and nucleation. Their less closely packed structures enhance mass transport, lithium-ion accommodation, and tolerance to volume change.
As an example, Figure 1 shows cycling performance of V2O5 electrodes in pure form (a), after Sn doping (b), and in the nano-belt configuration (c) [1,2]. Both the pure and Sn-doped electrodes exhibit an initial drop in specific capacity followed by an activation period that is somewhat longer for the Sn-doped electrode than for the pure electrode. The specific capacity of the pure electrode decays to about 180 mAh g–1 within 50 cycles. Notably, the Sn-doped electrode retains nearly its maximum capacity of 320 mAh g–1 throughout 50 cycles. Given the similar morphologies of these two electrodes, shown in Fig. 2(a) and (b), the change in capacity is most likely due to a chemical or electronic structure effect brought about by Sn-doping.
In contrast, the Na400 nano-belt electrode, prepared by reaction of V2O5 with H2C2O4 and NaNO3 and subsequent calcining to 400 °C, exhibits a steady yet slightly increasing capacity with cycling. The capacities of the pure V2O5 electrode (a) and the nano-belt electrode (c) become similar at about 40 cycles. This similarity may reflect changes in surface area of the pure electrode. Initially, the nano-belt electrode has, due to its well-formed belt structure [Fig. 2(c)], lower surface area than does the pure electrode. With cycling time the pure electrode eventually loses surface area, reaching a point similar to that of the nano-belt.
The extent of other factors, such as surface and bulk defects and volume change, are currently under investigation. This presentation will consider V2O5 electrodes and a new lithium titanate electrode as two model materials to illustrate the influences of doping, surface defects and carbon coating, and nanostructures on the lithium-ion intercalation properties.
1. Y. Li, J. Yao, E. Uchaker, M. Zhang, J. Tian, X. Liu, and G. Cao, J. Phys. Chem. C, 117, 23507 (2013).
2. S. Liang, T. Chen, A. Pan, D. Liu, Q. Zhu, and G. Cao, ACS Appl. Mater. Interfaces, 5, 11913 (2013).