bluuebunny/crossref_metadata_2025_split huggingface dataset:
HQ - US Army Development of High Voltage Olivine Cathode
Authors: Allen Jan L. , Delp Samuel A. , Wolfenstine Jeff , Jow T Richard , Liu Dong , Kim Chi-Su , Cho Myunghun , Guerfi Abdelbast , Zaghib Karim 
Published: February 2020

The need for environmentally friendly, safe, stable, and low cost materials for application in lithium-ion batteries has led to strong interest in developing olivine-type LiMPO4 (M = Fe, Mn, Co, Ni) cathode materials. Among them, LiFePO4 (LFP) has been extensively studied and commercialized. However, LFP has some special shortcomings in practical applications, such as low potential plateau (3.4 V vs. Li/Li+) and small packing density (due to the inclusion of large-volume carbon), which lead to relatively low specific energy density (580 Wh kg-1). Whereas LiCoPO4 (LCP) in the olivine family has been considered as an attractive cathode candidate due to the large theoretical capacity (167 mAh g-1), high operating voltage (4.8 V vs. Li/Li+) and high specific energy density (800 Wh kg-1).
However, LCP suffers from severe capacity fade due to the low intrinsic electronic/ionic conductivity, structure deterioration and electrolyte decomposition [1]. In this work, Hydro Quebec and US Army Research Laboratory dedicated to develop the high voltage olivine cathode. Specifically, partially Co-substitution strategy with a carbon coating was successfully used to improve the cycling stability of LCP cathode [2]. FIG. 1 shows the cyclability of substituted-LCP olivine cathode at room temperature under C/3 rate, from which no obvious capacity loss was observed in 100 cycles. Moreover, phosphate based cathodes may provide higher abuse tolerance than oxides at a given voltage due the strong covalent band of P-O. Therefore, the substituted high voltage LCP olivine cathode has the apparent potential to be a next decade success story in lithium-ion technologies and to find large application in the next generation lithium-ion batteries.

References

[1] K. Tadanaga, F. Mizuno, A. Hayashi, T. Minami, M. Tatsumisago, Electrochemistry
71, 1192 (2003).
[2] J. L. Allen, J. L. Allen, T. Thompson, S. A. Delp, J. Wolfenstine, T. Richard Jow, J. Power Sources, 327, 229 (2016).

Figure 1
Direct Visualization of Li Dendrite Growth Process at Short-Circuit Condition Via Transmission X-Ray Microscopy
Authors: Park Jeung Hun , Raj Abhishek , Steingart Daniel A 
Published: February 2020

Lithium is one of the most favorable materials for next-generation secondary energy storage devices due to its low redox potential, high gravimetric/volumetric capacities, and fast reaction kinetics [1]. However, the use of metallic lithium as the anode has been largely limited by the inherent safety concerns with lithium dendrite growth - causing short-circuits, leading to thermal runaway reactions, and fires/explosions [2]. Many efforts have been devoted to understanding dendrite morphologies with the influencing factors - temperature, electrolyte composition, current density and over-potentials [3]. However, the studies are limited to the nucleation and growth of Li dendrite at early stages [1,2]. At present, the growth mechanism and morphological changes taking place in Li dendrite formation near/after short-circuit condition, which presumably form the basis for its improved performance and safety, are not well understood.
Recent advances in in situ electrochemical transmission X-ray microscopy (EC-TXM), with its unique ability to provide simultaneous temporally and spatially resolved information as well as electrochemical parameters, enable exploration of the underlying physics of the electrochemical reactions that occur at the surface and inside of secondary energy storage devices during cycling [4,5]. Here, we focus the direct visualization of the propagation of Li dendrites at short-circuit condition using in situ EC-TXM. After the short-circuit, we follow three-dimensional morphological and microstructural changes of Li dendrites to explore relationships between electrochemical parameters and failure mechanisms during cycling. We further characterize the structural evolution of Li dendrites using in situ X-ray diffraction.

References:

[1] D. Lin, Y. Liu, & Y. Cui. Nat. Nanotechnol. 12, 194−206 (2017).
[2] W. Xu, J. Wang, F. Ding, X. Chen, E. Nasybulin, Y. Zhang, & J.-G. Zhang. Energy Environ. Sci. 7, 513−537 (2014).
[3] D. X. Liu, S. Frisco, P. Mandal, J. Whitacre, S. Litster, C. T. Love, & K. Swider-Lyons. ECS Meeting Abstracts MA2016-01 213.
[4] P. R. Shearing, D. S. Eastwood, R. S. Bradley, J. Gelb, S. J. Cooper, F. Tariq, D. J. L. Brett, N. P. Brandon, P. J. Withers, & P. D. Lee. Microsc. Microanal. 27, 19−22 (2013).
[5] J. Nelson, S. Misra, Y. Yang, A. Jackson, Y. Liu, H. Wang, H. Dai, J. C. Andrews, Y. Cui, & M. F. Toney. J. Am. Chem. Soc. 134, 6337−6343 (2012).
[6] We gratefully acknowledge funding supports from the BP Carbon Mitigation Initiative.
Capturing Solid Solutions during a First-Order Phase Transition of Li1+XMn2O4
Authors: Song Bohang , Veith Gabriel M , Whitfield Pamela , Schmidt Robert , Kirkham Melanie J. , Huq Ashfia 
Published: February 2020

Lithium-ion batteries (LIBs) offering the highest energy density among the known battery chemistries are the major contenders for both transportation and stationary storage applications. In order to satisfy the demands of energy density for these applications, new full cell configuration with either improved working voltage or specific capacity is needed to further enlarge its energy density. One candidate that has received a great deal of attention is the spinel cathode LiMn2O4, which offers the advantages of a high operating voltage (4.0 V vs. Li+/Li) and an excellent rate capability. Nonetheless, the relatively low specific capacity of 125 mAh·g-1 is mainly due to the restricted operating voltage between 3 and 4.5 V. In theory, LiMn2O4 cathode can deliver a capacity of ∼297 mAh·g-1 when 2 mole of lithium ions are inserted/extracted into/from both 8a tetrahedral and 16c octahedral sites of the spinel lattice at the voltages of, respectively, ∼4.0 and ∼2.7 V.1 Phase transition related to 4.0 V plateau is highly reversible, involving only two similar cubic spinel phases. However, phase transition related to 2.7 V plateau is partly reversible because a cubic spinel transforms to a tetragonal spinel with Jahn-Teller distortion occurring as a result of Mn3+ formation. The increase in the axial ratio from c/a = 1.0 in the cubic phase to c/a = 1.6 in the tetragonal phase due to the cooperative Jahn-Teller distortion leads to a fracture of large particles, which induces a loss of electrical contact with the current collector upon cycles.2 These effects cause serious capacity fading. However, the dynamic process of this phase transition has never been fully understood due to a lack of characterization techniques.
Based on the above considerations, we report an in operando neutron diffraction study to fully understand the ~2.7 V related phase transition in the Li1+xMn2O4 spinel upon electrochemical cycling. We found solid solution formation upon reversible discharge and charge process, although a first-order phase transition is widely believed. The solid solution formation is possibly due to a thick electrode configuration that we applied and a large overpotential it could generate, which is cosistent with the phenomenon that observed under high-rate charging/discharging of LiFePO4 using in situ synchrotron XRD.3

J. B. Goodenough, M. M. Thackeray, W. I. F. David, P. G. Bruce, Rev. Chim. Miner., 1984, 21, 435.

S.-H. Kang, J. B. Goodenough, and L. K. Rabenberg, Chemistry of Materials, 2001, 13, 1758-1764.

H. Liu, F. C. Strobridge, O. J. Borkiewicz, K. M. Wiaderek, K. W. Chapman, P. J. Chupas, C. P. Grey, Science 344, 7 (2014).
New Lithium-Excess High-Capacity Positive Electrode Materials with Reversible Three-Electron Redox Reaction of Mo3+/Mo6+
Authors: Hoshino Satoshi , Ichikawa Shinnosuke , Ozaki Tetsuya , Inamasu Tokuo , Yabuuchi Naoaki 
Published: February 2020

The demand for the increase in energy density of lithium batteries is steadily growing. The use of three-electron redox of transition metals is expected to be an important strategy to further increase the energy density of positive electrode materials with less transition metal ions. Recently, our group has reported that Mo3+ ions are diluted in lithium-excess oxides, Li2Ti4+O3, Li3Nb5+O4, and Li4Mo6+O5, which have higher lithium contents, and proposed as a new series of high-capacity electrode materials.[1] For instance, Li9/7Nb2/7Mo3/7O2 delivers a large reversible capacity of ca. 280 mAh g-1, which nearly corresponds to the theoretical capacity based on Mo3+/Mo6+.
In this study, this concept is extended into other lithium-excess compounds, and the use of Li3PO4 is targeted. A new binary system with Mo3+ is prepared according to the chemical formula of x Li3PO4 – (1 – x) LiMoO2. Since the molar mass of P is much smaller than that of Nb, the P-based samples are expected to deliver higher reversible capacity. Crystal structures and electrode performance in this binary system are systematically examined. A mixture of Li3PO4 and LiMoO2 was mechanically ball milled at room temperature with a ZrO2 container and balls. The samples of x = 0.4 (Li9/7P2/7Mo3/7O2) and 0.6 (Li11/8P3/8Mo1/4O2) show a relatively small reversible capacities in Li cells (Figure 1). In contrast, the sample of x = 0.2 (Li7/6P1/6Mo2/3O2) delivers the highest reversible capacity of ca. 330 mAh g-1with relatively higher operating voltage compared with the samples without P ions.[1]
From these results, we will discuss the possibility of a new series of high-capacity positive electrode materials with Mo3+ions for rechargeable lithium batteries.

Reference

[1] S. Hoshino, et al., and N. Yabuuchi, ACS Energy Letters, 2, 733 (2017).

Figure 1
Improved High-Voltage Stability of NCM523 Cathode Using Functional Electrolyte Additive
Authors: Kim Jae-Hee , Pham Hieu Quang , Lee Hee-Yeol , Hwang Eui-Hyung , Kwon Young-Gil , Song Seung-Wan 
Published: February 2020

Advanced portable electronics, electric vehicles and grid-based energy storage systems demand higher energy density Li-ion batteries than conventional ones as power sources. The energy density of Li-ion batteries can increase by increasing the specific capacity of cathode material, which can increase by raising the charge cut-off voltage. Among various cathode materials, nickel-rich three-components layered oxides of Li(Ni1-x-yCoxMny)O2 (NCM, 1-x-y ≥ 0.5) have been considered as prospective candidates for high-energy density Li-ion batteries because of higher capacity and lower cost than Ni-lean oxides. However, their high-voltage performance is difficult to achieve due to limited anodic stability of conventional electrolyte above 4.2 V vs. Li/Li+ and instability of cathode material at highly charged state. Under such an aggressive charge condition, cathode-electrolyte interfacial reactions often cause a degradation of cathode material and electrolyte consumption by oxidative decomposition of electrolyte, resulting in a rapid performance fade.1-3 We have demonstrated that the use of high-voltage electrolyte additive(s) is efficient and economic because they in situ form a surface protective layer at the cathode during high-voltage cycling, and improve the interfacial stability and cycling performance.1-3

Here we report the development of phosphorus-based additive for the NCM523 cathode to the charge cut-off voltage of 4.6 V. X-ray photoelectron spectroscopic and infrared spectroscopic studies on cathode-electrolyte interfacial phenomena and their correlation to cycling performance would be discussed in the meeting.

Acknowledgements

This research was supported by Ministry of Trade, Industry & Energy (R0004645) and Creative Human Resource Development Consortium for Fusion Technology of Functional Chemical/Bio Materials of BK Plus program by Ministry of Education of Korea.

References

1. Y.-M. Lee, K.-M. Nam, E.-H. Hwang, Y.-G. Kwon , S.-W. Song, J. Phys. Chem.
C, 118, 10631 (2014).
2. D. T. Nguyen, J. Kang, K.-M. Nam, Y. Paik, S.-W. Song, J. Power Sources,
303
, 150 (2016).
3. J. Kang, H. Q. Pham, D.-H. Kang, H.-Y. Park, S.-W. Song, J. Alloys & Compds, 657, 464 (2016).
Study of the Effect of Lithium Precursor Choice on Performance of Nickel-Rich NMC
Authors: Fitch Brian , Yakovleva Marina 
Published: February 2020

According to market research, use of NMC cathode materials for electric vehicle applications will increase dramatically over the next decade. Specifically, migration toward nickel rich NMC532, NMC622 and NMC811 appears likely in all major xEV markets (1).
Nickel-rich layered cathode materials such as LiNi0.8Co0.15Al0.05O2 (NCA) and nickel-rich LiNi1-x-yCoxMnyO2 (NMC), where Ni content is ≥0.6 moles can deliver high specific capacities of over 200 mAh g-1. However, the challenges surrounding synthesis of these materials are well documented (2), (3), (4). As nickel content increases the choice of lithium precursor, LiOH.H2O or Li2CO3, can have a dramatic effect on the performance of these cathode materials.
Here we report the advantages of using lithium hydroxide as the lithium precursor on the performance of nickel-rich NMC cathode materials. Specifically we will show that using lithium hydroxide as the lithium precursor results in:

Superior physical properties, such as higher tap and packing density, can be achieved at lower synthesis temperatures for nickel-rich NMC materials.

Improved material crystallinity as observed by x-ray diffraction, greater structural purity and less mixing of Ni2+ in the lithium layer determined by Rietveld refinement, leading to improved power performance.

Significant cost reduction due to increased process through-put.

Higher energy density materials at lower production energy consumption.

Also in this study statistical design of experiments has been used to evaluate the effect of temperature, nickel content and synthesis temperature on NMC discharge rate capability and lithium content in the lithium layer. The results show statistically significant interaction between temperature, nickel content and lithium precursor. Linear regression modeling of the DOE data predicts as nickel content in NMC increases, synthesis temperature has a dramatic effect on high rate discharge capacity. The model predicts that the optimum synthesis temperature for NMC622 is 850oC. At this temperature material synthesized using LiOH
.
H2O as the lithium precursor performs significantly better under high rate discharge conditions compared to material synthesized using Li2CO3.

References

Avicenne Energy, International Battery Seminar and Exhibit, March 20th, 2017.

B. H. Kim, et al., The effect of oxygen pressure on the synthesis of LiNiO2. Solid State Phenomena, Vols. 124-126, (2007), p. 1043-1046

P. Kalyani, N. Kalaiselvi, Various aspects of LiNiO2 chemistry: A Review. Science and Technology of Advanced Materials, 6, (2005), p. 689–703

Kim, M.-H., Shin, H.-S., Shin, D. & Sun, Y.-K., Synthesis and electrochemical properties of Li[Ni0.8Co0.1Mn0.1]O2 and Li[Ni0.8Co0.2]O2 via co-precipitation. Journal of Power Sources, (2006), 159, p. 1328-1333

Figure 1
Synthesis and Electrochemistry of High Energy LiVOPO4 with Enhanced Electronic and Ionic Conductivity
Authors: Shi Yong , Zhou Hui , Omenya Fredrick , Whittingham M. Stanley 
Published: February 2020

Lithium ion batteries (LIBs) have been widely used in many fields as power suppliers for mobile equipments. Recently, ε-LiVOPO4 has been regarded as a promising multi-electron cathode material that is capable to intercalate two Li per vanadium to achieve a very high theoretical capacity of 318 mAh/g, which exceeds any cathode material in the market today. However, the experimental capacity at useful current densities currently falls short of the theoretical one, and there is no data on long-term cycling behavior. In this study, pure ε-LiVOPO4 was successfully synthesized by an optimized solid-state reaction. This material demonstrates capacities close to the theoretical at moderate current densities. The long-term cycling data was obtained over various voltage windows. The electrochemical results demonstrate that this material suffers capacity loss upon long-term cycling. It is found the phase transformation from LiVOPO4 to VOPO4 is not completely reversible after several cycles, which is likely driven by low electronic and Li ionic conductivity. In this work, different carbon additives were applied to increase electronic conductivity; and surface modification was conducted to improve ionic conductivity. The results demonstrate that the optimized ε-LiVOPO4 has achieved great improvements of electrochemical performance in terms of capacity, rate capability, reversibility and cyclibilty.
This project is supported by the U.S. Department of Energy’s Office of Energy Efficiency and Renewable Energy (EERE) program under Award No. DE-EE0006852.
Understanding the Evolution of Cathode Material in Electrochemical Process at Multi-Scale
Authors: Wang Xuelong , Hu Enyuan , Bak Seong-Min , Liu Yijin , Yu Xiqian , Xiao Ruijuan , Li Hong , Chen Liquan , Yang Xiao-Qing 
Published: February 2020

Nowadays it’s well recognized that developing renewable energy resources and energy conservation are key technique for us to meet with a sustainable future. Lithium ion batteries (LIBs) stood out as promising candidates for energy storage devices. Further increasing energy density and reducing cost are the major goals of researchers. Though for now, on increasing energy density more progress seems to be made with anode rather than cathode, there are still several kinds of cathode material with great expectations such as high-voltage LiCoO2, Li-rich material and Nickel-rich layered material. However, they all suffer from surface degradation, transition metal reduction and structure instability accompanied by oxygen release to some extent during the electrochemical process. Therefore, understanding the chemical compositional change and local structure transformation inside the cathode material is essential for us to contain these hazardous deteriorations from the beginning.
Transmission X-ray microscope (TXM) has been proven to be a powerful experimental method for investigation on material systems at particle level especially when energy resolution is feasible and combined with data-mining technique. With this technique, we can monitor chemical compound evolution and their spatial distribution in cathode material during the electrochemical process. More excitingly it shows the possibility to see the emergence of unexpected minor phase which isn’t anticipated in the first place. Furthermore, with the aid of atomic DFT calculation and mesoscale mechanical simulation we could relate the practical performance of material in real cell with the subtle changes inside a particle. In this report by combining these methods at different length scale we offer our own insights on transition metal dissolution and precipitation, variation of chemical composition in different region of a single particle and the behavior of transition metal at different charge voltage. In general, we hope these findings could benefit our understanding on the material evolution in actual electrochemical process.

Acknowledgment

The work done at Brookhaven National Laboratory were supported by the Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Vehicle Technologies of the U.S. Department of Energy through the Advanced Battery Materials Research (BMR) Program, including Battery500 Consortium under contract DE-SC0012704. Research conducted at ORNL's Spallation Neutron Source was sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, U.S. Department of Energy.
Oxygen Evolution and Phase Transformation in LiCoO2 Cathode: A Phase-Field Modeling Study
Authors: Yurkiv Vitaliy , Sharifi-Asl Soroosh , Ramasubramanian Ajaykrishna , Shahbazian-Yassar Reza , Mashayek Farzad 
Published: February 2020

Thermal runaways, triggered by oxygen release from the oxide cathode materials, pose a major safety concern for widespread application of lithium ion batteries. To allow for a deeper understanding of the processes leading to the thermal runaway, a combined modeling and experimental work of phase transformation and the subsequent oxygen release in LiCoO2 electrodes was undertaken. This contribution presents the modeling part and the accompanied abstract in this meeting reports the experimental details, thus only a brief experimental description is given here. Commercially available and chemically de-lithiated LiCoO2 samples were used. Utilizing in-situ aberration-corrected scanning transmission electron microscopy (STEM) and in-situ electron energy loss spectroscopy (EELS) techniques, phase transformation and the oxygen release from LiCoO2 samples were investigated in the temperature range between 25 °C and 450 °C.1

In order to interpret the experimental measurements and to identify factors governing phase transformation and the subsequent oxygen release, a multiphase-field model (PFM) is established to represent the coupled mechanical, chemical and transport behavior occurring in the LiCoO2 electrodes. The PFM was developed using the MOOSE framework.2,3 The model captures both the kinetics of the oxygen release by employing Fick’s diffusion law, as well as the stress build-up. This is achieved by coupling the evolution equation of the phase-field variables (i.e., oxygen concentration, existed phases) to the mechanical equations allowing to study diffusion induced phase transformation and stress generation. The model was validated against the above described experimental measurements by comparing the rate of phases growth and their thicknesses. This comparison allows the PFM to predict the oxygen composition depth and the stress profile in the layered, spinel and rock salt structures of the LiCoO2 during the heating. The simulation results indicate that the generated stress slows down the oxygen release, and changes the local oxygen concentration within the phases. In addition, the temperature ranges of the critical oxygen release were identified. Thus, this combined work provides suggestions for a safe operating window of the LiCoO2 electrodes.
References
1. S. R. Sharifi-Asl, F. Soto, A. Nie, Y. Yuan, H. Asayesh-Ardakani, T. Foroozan, V. Yurkiv, B. Song, F. Mashayek, R. Klie, K. Amine, J. Lu, P. Balbuena, R. Shahbazian-Yassar, Nano Lett., 17, 2165-2171 (2017).
2. M. R. Tonks, D. Gaston, P. C. Millett, D. Andrs, and P. Talbot, Comput. Mater. Sci., 51, 20–29 (2012).
3. D. Schwen, L. K. Aagesen, J. W. Peterson, and M. R. Tonks, Comput. Mater. Sci., 132, 36–45 (2017)
Improvement of Specific Capacitance in Lithium Ion Batteries By Mesoporous Carbon Hybrid Nanostructures
Authors: Dorvilien Valerio , Rojas Carolina Valeria , Santa Cruz Neida , LopezdeVictoria Monica , Rivera Kevin , Limbu Tej B. , Mendoza Frank , Morell Gerardo , Weiner Brad R. 
Published: February 2020

We propose a low cost and simple method to prepare carbon hybrid structure-based electrodes in this study. Hybrid-structure Carbon Nanostrures were obtained using a zeolite as a template. The resulting carbon nanostructures are mostly configured by Graphene and multiwall carbon nanotubes (G/MWCNTs). The G/MWCNTs were dispersed onto the shallow surface of alumina foil forming as the electrodes. The electrical conductivity and dispersed morphology of the G/MWCNTs -based conductive electrode were examined by atomic force microscope (AFM), scanning electron microscope (SEM) and transmission electron microscope (TEM). Using the standard method we assembled the Lithium Ion Battery in the Ar-filled glove box, we used LiPF6 with EC:DMC::1:2 ratio as the electrolyte, lithium foil as the counter electrode and G/MWCNTs material. The specific capacity and cycle-life stability of the G/MWCNTs-based lithium ion battery was investigated by cyclic voltammetry analysis.