bluuebunny/crossref_metadata_2025_split huggingface dataset:
Lithiated Polyacrylic Acid Binder to Enhance the High Rate and Pulse Charge Performances in Graphite Anodes
Authors: Chiu Kuo-Feng , Leu Hoang-Jyh , Su Shih-Hsuan , Wu Rong-Zong 
Published: February 2020

Polyacrylic acid (PAA) was used as water-soluble binder for graphite anodes of lithium ion batteries, and was further lithiated by titration using LiOH aqueous (Li-PAA). PAA and Li-PAA films with different degree of lithiation were controlled by adjusting the pH value during titration. Graphite anodes with conventional polyvinylidene fluoride (PVDF) binder were also fabricated for comparison. The graphite anodes with PAA binder exhibit a low capacity of 25 mAh/g at high current rate of 2 C, whereas the electrode with PVDF binder exhibits a higher capacity of 75 mAh/g. However, graphite anodes with the Li-PAA binder show greatly improved high-rate capability, with a 2 C capacity (> 225 mAh/g) three times higher than the conventional anodes. These results can be attributed to the increase of Li+ ion concentrations in the vicinity of the active materials, which reduces the charge transfer resistance at the interface of electrode/electrolyte, as measured by electrochemical impedance spectroscopy. In addition, to test the durability of pulse current charge in the conditions of green grids, all samples were operated with 50 pulses of 5 C currents during a 0.2 C charge process to simulate the conditions of green energy grid. It was found that the graphite anodes with Li-PAA of higher Li+ ion concentrations exhibit higher durability under pulse current charge, compared with the conventional anodes. However, too high a Li+ ion concentration weakens the binding strength, and therefore a high stability Li-PAA/graphite anode requires optimized Li+ ion concentration. The results indicate that Li-PAA is an appropriate binder for anodes in green energy grid application.
Primary Influence Factors on Li-Ion Battery for High Power and Low Temperature Applications
Authors: Gu Hong-Hui , Gao Lei , Cheng Guangyu , Li Lanqiang 
Published: February 2020

Lithium ion batteries are currently being considered for using in a wide range of aerospace applications[1]. Batteries for these aerospace applications, such as aircraft and UAV (unmanned aerial vehicle), are required to operate at high rates(up to 15C or higher) and low temperatures (-40°C or lower). To address these requirements, a series of experiments have been undertaken to empirically determine those factors that limit the performance. For example, a reference electrode is introduced in the battery. The reference electrode enables the diagnosis of individual electrodes. The voltage profile of 50C high power pulse discharge is shown in Figure 1 left. The result indicates that the positive voltage drops from 4.500V to 2.638V, and that the negative voltage rises from 0.083V to 0.689V, which means that the positive electrode dominates the polarization. Hence, further experiments would be aimed at the positive side, such as the weight loading and diverse positive materials. The voltage profile of 5C pulse discharge at -40°C is described in Figure 1 right. The result indicates that the positive voltage drops from 4.500V to 3.595V, and that the negative voltage increases from 0.054V to 0.925V, which means that the majority of the polarization is ascribed to the positive side and negative side, no dominations could be seen from that result. In order to reveal the limiting factors, further experiments could be aimed at the electrolyte or the separator possibly.
Fig. 1 Voltage profile for 50C pulse discharge at 25°C and Voltage profile for 5C pulse discharge at -40°C
References
[1] Richard Van Noorden.Nature.507 (2014)26-28.

Figure 1
Lithium Plating Simulations in Commercial Lithium-Ion Batteries during Low-Temperature Charging
Authors: Cabañero Martínez Marian , Gebel Ajana , Lorrmann Henning , Sextl Gerhard , Hein Simon , Kallo Josef , Latz Arnulf 
Published: February 2020

Fast charging of Li-ion cells is one of the main challenges in automotive battery applications. As a particular problem at low temperatures and high charging rates, lithium deposits as metal on the anode surface instead of intercalation. Capacity loss resulting from lithium plating is the main aging effect at low temperatures [1][2]. Moreover, the deposited Li can form dendritic deposits which are known to trigger internal short circuits when piercing through the battery separator [3].
In this work a micro-scale model [4] [5] was used to investigate the onset of lithium plating during charging at low temperatures in commercial lithium-ion batteries. The model was parameterized and validated with materials from NMC-Graphite commercial cells. The cells were opened in a glovebox with controlled argon atmosphere and the transport properties of the electrode materials at different temperatures were measured by Potentiostatic Intermittent Titration (PITT) and Galvanostatic Intermittent Titration Technique (GITT). The mean particle size, thickness and porosities were determined by SEM microscopy (Figure 1a).
The model predictions of the onset temperature for lithium deposition on graphite electrodes were validated through experimental measurements on laboratory full cells. The reversible plating can be identified by the Li stripping plateau during discharge. Figure 2 shows the onset temperature (-10 °C) of lithium plating during CCCV charge at 1C. Irreversible plating on the graphite electrode was measured by inductively coupled plasma optical emission spectroscopy (ICP-OES).
The developed model is used to establish suitable operating conditions that avoid lithium plating in Li-ion batteries while maximizing charge rates and minimizing heating requirements.

[1]
V. Zinth, C. von Lüders, M. Hofmann, J. Hattendorff, I. Buchberger, S. Erhard, J. Rebelo-Kornmeier, A. Jossen, R. Gilles, J. Power Sources 271 (2014) 152–159.

[2]
C. Uhlmann, J. Illig, M. Ender, R. Schuster, E. Ivers-Tiffee, J. Power Sources 279 (2015) 428-438.

[3]
Z. Li, J. Huang, B. Yann Liaw, V. Metzler, J. Zhang, J. Power Sources 254 (2013) 168-182.

[4]
A. Latz, J. Zausch, J. Power Sources 196 (2011) 3296–3302.

[5]
G. B. Less, J. H. Seo, S. Han, A. M. Sastry, J. Zausch, A. Latz, S. Schmidt, C. Wieser, D. Kehrwald, S. Fell, J. Electrochem. Soc 159 (2012) A697-A704

Figure 1
Computational Analysis on the Effects of Different Electrode Designs on the Electrochemical Performance of Lithium Ion Batteries
Authors: Appiah Williams Agyei , Park Joonam , Byun Seoungwoo , Ryou Myung-Hyun , Lee Yong Min 
Published: February 2020

Li-ion batteries (LIBs) as an energy storage device have been established as a leading and a promising candidate for automotive and aerospace applications. But to meet the various application requirements, the energy and power density of LIBs need to be optimized for a given electrode material by controlling its porosity and thickness. Changes in electrode thickness and porosity affect the electrochemical performance of LIBs. Thus we employ a mathematical model to study and optimize the electrochemical performance of Graphite/ LiNi0.6Co0.2Mn0.2O2LIB cells with different cathode thicknesses and porosities. A non-linear least square method is used to provide a better understanding of the different porosities and thicknesses on Li-ion transport in both liquid and solid phases. Ragone plots are generated for the various cell designs where the specific energy and average specific power are evaluated. The LIB cells are optimized for discharge times ranging from 10 h to 2 min in order to map the maximum performance of this electrode chemistry under wide operating range. The study allows us to ascertain the ability of this chemistry to be used in a particular application.
The solid phase Li-ion diffusion coefficient decreased with an increase in current rate. The salt concentration gradient increased with an increase in cathode thickness and porosity at high rate. Based on the experimental data and simulation results from this study, it can be concluded that both solution and solid phase diffusion limitation are the major limiting factors during high rate discharges in thick and less porous electrodes. The optimized designs derived in this work are expected to be starting point for battery manufacturers and to help decrease the time to commercialization.

References

1. W. A. Appiah, J. Park, L. Van Khue, Y. Lee, J. Choi, M.-H. Ryou and Y. M. Lee, Electrochimica Acta, 187, 422 (2016).
2. P. Arora, M. Doyle, A. S. Gozdz, R. E. White and J. Newman, Journal of power Sources, 88, 219 (2000).
3. V. Srinivasan and J. Newman, Journal of the Electrochemical Society, 151, A1530 (2004).

Acknowledgement

This work was supported by the Sebang Global Battery.

Figure 1
First-Principle Calculations on Structure, Thermodynamics and Electrochemistry of Si-O-C Electrodes
Authors: Rohrer Jochen , Albe Karsten 
Published: February 2020

Siliconoxycarbides (SiOC) have emerged as promissing electrode material for Li-ion batteries, showing capacities of up to 800 mAh/g and reasonable cycling stability. SiOCs are amorphous networks that are typically obtained by pyrolysis of various precursors. Depending on the choice of the precursor and the pyrolysis temperature, SiOCs with different chemical compositions and thus different morphologies, including an additional free carbon phase, can be obtained. Moreover, Si or Sn nanoparticles can be embedded into SiOC networks, either by mixing or by modification of the precursor. In this way, a further increase of Li capacities has been demonstrated.
Despite numerous experimental investigations our understanding of atomic structure and electrochemical behaviour of SiOCs is still limited. In this contribution, density functional theory (DFT) calculations are used to model lithiation of SiOC from a an atomistic and electronic perspective. We first address the challenge of designing realistic structure models. For pristine SiOC, the lack of the existence of a crystalline phase prevents straightforward structure-generation using a cook-and-quench approach. In recent literature, SiOC models that were obtained by replacing O by C in amorphous SiO2 networks have been presented. However, such models suffer from the fact that O is only 2-fold coordinated in SiO2, while C prefers a 4-fold coordination in the vicinity of Si. Therefore, the carbon in such SiOC models is expected to be more reactive than in reality. We present a strategy that results in model structures that consist of Si and C that are mainly 4-fold coordinated while O is 2-fold coordinated. In addition, a free carbon phase is included in our models. After structural optimization and thermodynamic characterization, we study Li insertion. In particular we present information about Li storage sites, energetic evolution (including voltage profiles), structural evolution (including specific volume changes) and elastic properties. We compare our results to experiment and previous modelling studies.
Lithium Ion Solvation and Diffusion in Bulk Organic Electrolytes from First Principles Molecular Dynamics
Authors: Ong Mitchell T. , Lordi Vincenzo , Draeger Erik W. , Pask John E. 
Published: February 2020

Lithium-ion secondary batteries are commonly used to power many consumer devices such as handheld phones, laptops, portable music players, and even electric vehicles. One of the key properties that influence the performance of lithium-ion batteries is the ionic conductivity of the electrolyte (i.e., the movement of Li ions from one electrode to another). This is dependent on the speed at which Li ions diffuse across the cell and related to the solvation structure of the Li ions. The choice of solvent can greatly impact both solvation and diffusivity of Li ions. In this work, we use first principles molecular dynamics to examine the solvation and diffusion of lithium ions in the bulk organic solvents ethylene carbonate (EC), ethyl methyl carbonate (EMC), and a mixture of EC/EMC. We find that Li ions are solvated by either carbonyl or ether oxygen atoms of the solvents and sometimes by the PF6 anion. Li+ prefers a tetrahedrally-coordinated first solvation shell regardless of which species are involved, with the specific preferred solvation structure dependent on the organic solvent. In addition, we calculate Li diffusion coefficients in each electrolyte, finding slightly larger diffusivities in the linear carbonate EMC compared to the cyclic carbonate EC. The magnitude of the diffusion coefficient correlates with the degree of Li+ solvation. Corresponding analysis for the PF6 anion shows greater diffusivity associated with a weakly-bound, poorly defined first solvation shell. Results from this work can be used to design new bulk electrolytes that will improve the performance of current Li-ion batteries.
Theoretical Investigation of the Oxygen Reduction Reaction in Non-Aqueous Electrolytes
Authors: McKee William C. , Rawal Saurin , Xu Ye 
Published: February 2020

The non-aqueous Li-air (O2) battery has generated a great deal of attention because it potentially possesses far greater gravimetric energy storage density than today’s rechargeable battery technologies.1-4 This has re-kindled the research interest in the O2 reduction reaction (ORR) in non-aqueous electrolytes because the ORR is the central electrochemical process that occurs at a Li-air cathode. Currently Li-air cells suffer from poor cycling efficiency and low current density. Substantial improvements in these key aspects are critical to making rechargeable Li-air batteries a reality, for which it is necessary to understand the ORR and its reaction mechanism.
To that end, we have performed DFT-based theoretical studies of the ORR on metals. Previously we have shown that the intrinsic activity of oxygen reduction by Li forms a volcano-like trend with respect to the adsorption energy of oxygen on different metals.5 Similar to the hydrogen version of the ORR, Pt and Pd are likewise found to be the most active metals and are located at the top of the volcano. The aprotic nature of non-aqueous Li-O2 cells, however, makes the one-electron reduction of O2 to the superoxide anion (O2
-) possible besides concerted Li+/e
- transfer, and indeed often at higher potential than molecular LiO2.5 Our calculations, in conjunction with spectro-electrochemical studies, now identify O2
- as a common intermediate in dimethyl sulfoxide (DMSO) electrolytes containing proton or lithium.6 When the DMSO contains a poor proton source, O2
- appears as the first stable intermediate during the ORR, with H2O2 appearing at higher overpotentials. When DMSO contains a Li+ source instead, O2
- is again the first reaction intermediate, whereas surface LiO2 does not appear until the potential is much more negative of bulk Li2O2 formation potential. Therefore, the superoxide anion plays a key role in the ORR under a diverse range of electrode conditions, and needs to be taken into consideration when predicting the activity of ORR in non-aqueous Li-O2 cells.
1. P.G. Bruce, S.A. Freunberger, L.J. Hardwick, J.-M. Tarascon, Nat. Mater. 2012, 11, 19.
2. J. Lu, L. Li, J.-B. Park, Y.-K. Sun, F. Wu, K. Amine, Chem. Rev.
2014, 114, 5611.
3. A.C. Luntz, B.D. McCloskey, Chem. Rev.
2014
, 114, 11721.
4. R. Black, B. Adams, L.F. Nazar, Adv. Energy Mater.
2012, 2, 801.
5. G. K. P. Dathar, W.A. Shelton, Y. Xu, J. Phys. Chem. Lett.
2012, 3, 891.
6. Z. Peng, Y. Chen, P.G. Bruce, Y. Xu, Angew. Chem. Int. Ed.
2015, 54, 8165.
Free Energy Landscape for Lithium Solvation in Protic Ionic Liquids from Frirst Prinicples Simulations
Authors: Kachmar Ali , Carignano Marcelo , Laino Teodoro 
Published: February 2020

Ionic liquids are being considered as an alternative for Li-ion batteries electrolytes since many of them are non-flammable, which is one of the most problematic safety issues in Li-ion batteries [1-3]. In this particular case, we are investigating the solvation of lithium (Li+) in Ethylammonium Nitrate (EAN) [4-5] by means of first principles simulations and metadynamics simulations [6-8]. The structures of the local environment of the lithium cation and its coordination have been analyzed. The simulations show that the Li+cation undergoes different lithium coordination number with the nitrate ions. Analysis of the energy minima for the relevant lithium coordination is also discussed.

References

Handbook of Green Chemistry, Volume 6: Ionic Liquids, Edited by Peter Wasserscheid and Annegret Stark. Copyright©(2010) WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim, ISBN: 978-3-527-32592-4.

A. Leawndowski, Agnieszka Świderska-Mocek, Ionic liquids as electrolytes for Li-ion batteries-An overview of electrochemical studies, J. Power Sources 194, 601-609 (2009).

Douglas R. MacFarlane, Naoki Tachikawa, Maria Forsyth, Jennifer M. Pringle, Patrick C. Howlett, Gloria D. Elliott, James H. Davis, Jr., Masayoshi Watanabe, Patrice Simon, C. Austen Angell, Energy applications of ionic liquids, Energy Environ. Sci., 7, 232-250, (2014).

Robert Hayes, Stephen A. Bernard, Silvia Imberti, Gregory G. Warr, and Rob Atkin, Solvation of Inorganic Nitrate Salts in Protic Ionic Liquids, J. Phys. Chem. C., 118 (36), 21215–21225, (2014).

Meńdez-Morales, T.; Carrete, J.; O. Cabeza, ; Russina, O.; Triolo, A.; Gallego, L. J.; Varela, L. M. Solvation of Lithium Salts in Protic Ionic Liquids: A Molecular Dynamics Study. J. Phys. Chem. B, 118, 761−770, (2014).

R. Car and M. Parrinello, Unified Approach for Molecular Dynamics and Density-Functional Theory. Phys. Rev. Lett. 55, 2471, (1985)

A. Laio, M. Parrinello, Escaping free-energy minima. Proceedings of the National Academy of Sciences of the United States of America 99(20), 12562-12566, (2002).

M. Iannuzzi, A. Laio, M. Parrinello, Efficient Exploration of Reactive Potential Energy Surfaces Using Car-Parrinello Molecular  Dynamics, PRL 90, 238302 (2003).

CP2K, http://www.cp2k.org/
Understanding the Effect of Synthesis Conditions on the Electrochemical Performance of the Mn3+/Mn4+ Redox Couple in LiNi0.5Mn1.5O4.
Authors: Nagasubramanian Arun , Srinivasan Madhavi 
Published: February 2020

Research in rechargeable lithium ion battery (LIBs) systems has recently focussed on improving the operating voltage, specific capacity as well as safety. In this regard, nickel substituted spinel (LiNi0.5Mn1.5O4, LNM) is attractive as a cathode with an operating voltage of ~4.7V vs. Li/Li+. Nickel substitution in spinel LiMn2O4 was initially performed with the aim of stabilizing the material against phase transformation that arose due to co-operative Jahn-Teller distortion of the lattice. But it was discovered that the Ni2+/Ni4+ redox couple was active at a potential of ~4.7 V in a reversible manner[1]. This generated intense interest in this material. Although the material has proven to be robust and maintains structural stability during cycling, the existing electrolytes are unable support such high operating voltages and continue to remain a hurdle in the development of batteries based on this spinel. In this work, we are interested in understanding another redox couple based on Mn3+/Mn4+ which operates at ~2.8V vs Li/Li+ [1,2]. This redox couple has not been explored in detail and understandably so due to the attractive high voltage characteristics offered by the nickel redox couple. But the operating potential (~2.8V vs Li/Li+) makes it an ideal candidate as anode for aqueous rechargeable lithium battery systems (which would operate at ~ -0.24V vs SHE). Furthermore, the effect of co-operative Jahn-Teller distortion that occurs due to the average manganese valence reducing below 3.5 is minimized to a significant extent compared to the counterpart spinel LiMn2O4. It would be possible to insert approximately 0.75 mols of lithium before the average manganese valence reaches 3.5. This would give it a capacity of roughly 110 mAh.g-1. However there are only a few studies that investigate systematically the electrochemical performance of the Mn3+/Mn4+ redox couple in LNM.
In this work, we have investigated the effect of synthesis method and conditions on the electrochemical performance of LNM while storing and extracting lithium using the manganese redox couple in non-aqueous electrolytes. It was found that synthesis conditions had a significant effect on the specific capacity that could be obtained for the manganese redox couple. Lower temperatures of synthesis resulted in higher capacities. This is in contrast to the performance of the nickel redox couple where higher temperatures offered better capacities. Cyclic voltammetry, galvanostatic cycling and impedance measurements were performed to understand the origin of the differences in the behaviour. More results will be presented at the meeting.
References
[1] K. Amine, H. Tukamoto, H. Yasuda, Y. Fujita, J. Power Sources. 504 (1997) 604–608.
[2] K. Amine, H. Tukamoto, H. Yasuda, et al., J. Electrochem. Soc. 143 (1996) 1607–1613.
Stable Lithium Metal Anodes for Rechargeable Lithium Metal Batteries
Authors: Li Nian-Wu , Yin Ya-Xia , Yang Chun-Peng , Guo Yu-Guo 
Published: February 2020

Li metal is an ideal anode material for next-generation energy storage devices due to its extremely high theoretical specific capacity and the lowest negative electrochemical potential [1,2]. However, uncontrolled Li dendrite growth and the side reaction between Li metal and electrolytes have prevented its practical application in rechargeable Li metal batteries. In our contributions, artificial solid electrolyte interphase (SEI) layer and 3D current collector have been developed to address these issues [3,4].
In this presentation, we will introduce an artificial Li3PO4 SEI layer [3] fabricated by in situ reaction of polyphosphoric acid (PPA) with Li metal and its native film (Li2CO3, LiOH, and Li2O). The partial dissolution of the Li native film and formation of the SEI layer lead to a porous structure of the Li surface, thereby promoting Li dendrite formation and growth. In the ingenious design, the native film of Li metal is replaced by the stable and uniform Li3PO4 SEI layer. The artificial Li3PO4 SEI layer with thickness of 50 nm exhibits a smooth surface and a high Young’s modulus (10-11 GPa). Furthermore, the artificial Li3PO4 SEI layer is demonstrated to be stable in the electrolyte and during cycling in a Li|LiFePO4 battery system. The Li-conducting Li3PO4SEI layer can achieve uniform Li deposition, and reduce the side reaction between the Li metal and the electrolyte. Thus, the artificial SEI strategy we described is a promising route to tackle the intrinsic problems of Li metal anodes and other metal based anodes.
Furthermore, we will show that Li metal anode can be accommodated in the reserved pores of the 3D current collector [4] with a submicron skeleton and high surface area, thereby suppressing the Li dendrite growth and solving the associated problems of Li metal anodes. Because of the high electroactive area of the submicron 3D structure, the 3D current collector can improve the Li plating/stripping efficiency and reduce the resistance of the Li metal anode. The utilization of the 3D architecture to accommodate the Li metal anode will highlight the importance of rational design of current collectors and reveal a new avenue for developing Li metal anodes with a long lifespan.
References

Y.-X. Yin, S. Xin, Y.-G. Guo, L.-J. Wan, Angew. Chem. Int. Ed.
2013, 52, 13186.

W. Xu, J. L. Wang, F. Ding, X. L. Chen, E. Nasybutin, Y. H. Zhang, J. G. Zhang, Energ. Environ. Sci.
2014, 7, 513.

N.-W. Li, Y.-X. Yin, C.-P. Yang, Y.-G. Guo, Adv. Mater.
2015, DOI: 10.1002/adma.201504526.

C.-P. Yang, Y.-X. Yin, S.-F. Zhang, N.-W. Li, Y.-G. Guo, Nat. Commun.
2015, 6, 8058