bluuebunny/crossref_metadata_2025 huggingface dataset:
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
First-Principles Study on Charge Transport Mechanism of Lithium Sulfide (Li2S) in Lithium-Sulfur Batteries
Authors: Kim Do-Hoon , Lee Buyngju , Park Kyu-Young , Kang Kisuk
Published: February 2020

The lithium–sulfur chemistry is regarded as a promising candidate for next-generation battery systems because of its high specific energy (1675 mAhg-1). Although issues such as the low cycle stability and power capability of the system remain to be addressed, extensive research has been performed experimentally to resolve these problems. Attaining a fundamental understanding of the reaction mechanism and its reaction product would further spur the development of lithium–sulfur batteries. Here, we investigated the charge transport mechanism of lithium sulfide (Li2S), a discharge product of conventional lithium-sulfur batteries using first-principles calculations. Our calculations indicate that the major charge transport is governed by the lithium-ion vacancies among various possible charge carriers. Furthermore, the large bandgap and low concentration of electron polarons indicates that the electronic conduction negligibly contributes to the charge transport mechanism in Li2S
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
Analysis of Electrochemical Properties of Li Iron Phosphate Cathode Material Doped with Aluminium
Authors: Sirigineedi Jagadish Babu , Bhattacharya Indranil , Penumaka Rani
Published: February 2020

With the advent of Phospho-Olivines as cathode material for rechargeable lithium ion batteries in 1997 by Padhi et.al. intensive study with primary focus on LiFePO4 have been carried out owing to its certain advantages like low cost, non – toxic, environmental friendly, and high safety . Even with cathode materials like LiCoO2 with higher capacity than the LiFePO4, LiFePO4 is proven to be more stable since it is more tolerant to overcharge and discharge. However, the theoretical capacity is not attained till date at 1C current. The major problem lies with the low electronic conductivity and slow Li ion diffusion. To improve the conductivity several techniques have been proposed like carbon coating technique, heavy cation doping into the olivine structure etc. In this paper LiFePO4 was selectively doped with aluminum at the Fe position retaining the olivine structure and synthesized using a novel modified solid state synthesis method.
Optimized Temperature Effect of Li-Ion Diffusion with Layer Distance in Li(NixMnyCoz)O2 cathode Materials for High Performance Li-Ion Battery
Authors: Cui Suihan , Wei Yi , Liu Tongchao , Zheng Jiaxin , Wang Xinwei , Pan Feng
Published: February 2020

Understanding and optimizing temperature effects of Li-ion diffusion by analyzing crystal structures of layered Li(NixMnyCoz)O2 (NMC) (x + y + z = 1) materials are important to develop advanced rechargeable Li-ion batteries (LIBs) for multi-temperature applications with high power density. Combined with experiments and ab initio calculations, the layer distances and kinetics of Li-ion diffusion of NMC materials in different states of Li-ion de-intercalation and temperatures are investigated systematically. An improved model is also developed to reduce the system error of “Galvanostatic Intermittent Titration Technique” (GITT) with a correction of NMC particle size distribution. The Li-ion diffusion coefficients of all the NMC materials are measured from -25 to 50 °C. It is found that the Li-ion diffusion coefficient of LiNi0.6Mn0.2Co0.2O2 is the largest with the minimum temperature effect. Ab initio calculations and XRD measurements indicate that the larger Li slab space is benefited to Li-ion diffusion with minimum temperature effect in layered NMC materials.

Figure 1
Tuning Structural Stability and Lithium-Storage Properties By D-Orbital Hybridization Substitution in Full Tetrahedron Li2FeSiO4 Nanocrystal
Authors: Yang Jinlong , Zheng Jiaxin , Pan Feng
Published: February 2020

Full tetrahedron connected structures possess considerable potential as cathodes for Lithium-ion batteries (LIBs) due to more lithium storage sites to obtain high specific capacity. However, different from the full octahedron and octahedron/tetrahedron hybrid structures with coplanar or collinear, the tetrahedron network is connected by common vertex, which provokes structural instability and poor electrochemistry performance. Here, using first principles calculations combined with experiments, we found that a heavy distortion and big volume expansion during delithiation for full tetrahedron (LiO4, FeO4 and SiO4 tetrahedra) Li2FeSiO4 nanocrystal lead to phase change or even structure fracture, and the optimized Ti(IV) doped in Fe sites can enhance the coupling effect among the tetrahedra by the strong d-orbital hybridization and like “spring” to hold these tetrahedra and prohibit structure fracture. Meanwhile, the Ti(IV) doping can also shorten the distance of two adjacent Li sites to decrease the activation barrier for Li-ion diffusion. Furthermore, the n-type doping effect increases the electronic conductivity. This discovery can be extended to other tetrahedron structures as well, providing a general approach to develop promising next-generation cathode materials for high-energy and long-life lithium-ion batteries.

Figure 1
A Polyborosiloxane Binder for Silicon Battery Anodes in Lithium-Ion Batteries
Authors: Shariaty Darius Allen , Odom Susan A , Cheng Yang-Tse , Casselman Matthew D
Published: February 2020

Harnessing silicon (Si) as the anode material in lithium-ion batteries offers the possibility of a nearly ten-fold capacity increase over traditional graphite anodes. However, the 300% volume expansion and contraction upon charging and discharging hinders its practical use due to a significant loss in capacity with cycling.  Unique geometric arrangements of Si particles, as well as modifications of polymer binder, have resulted in advances in capacity retention over time, but many modifications are cost-prohibitive for producing a commercially viable electrode.  Our strategy to minimize the loss in capacity retention of this high-capacity anode material involves the utilization of a viscoelastic cross-linked polysiloxane polymer binders.  This presentation will discuss the mechanical properties and cycling characteristics of the electrodes prepared with this binder and comparable polymers. A highlight of our progress is a retention of charge capacity over >100 cycles.  In addition to the retention of capacity, we highlight the low cost and simple synthesis of this polymer binder.
Modeling and Electrochemical Characterization of a LiFePO6 / Activated Carbon Electrode for the Construction of a Hybrid Electrochemical Device with High Density of Energy and Power
Authors: Ramírez Tangarife Luis Adrián , Sanchez Saenz Carlos Ignacio , Roncancio Gomez Robin Alejandro
Published: February 2020

The lithium-ion batteries are a promising technology for be to use how energy sources for hybrid and electrical vehicles. Those batteries have the highest energy density among the secondary batteries for mobile applications.

However, their power density is not enough for to satisfy the requirements of the electrical vehicles. For this reason, it is proposed the construction of a hybrid electrochemical device using a lithium battery and an electrochemical capacitor.

The hybrid electrochemical device combines the features of the devices used for his construction, in this case, the high power density of the electrochemical capacitor and the high energy density of the lithium battery by which this hybrid device is ideal for electrical vehicles.    

The hybridization consists in to combine the material of battery electrode and the capacitor electrode in a new hybrid electrode.

In this work, the hybrid electrode is the combination of LiFePO6 whit high surface area carbon and a metallic current collector. The LiFePO6 was synthesized by a hydrothermal process using how precursor compound lithium hydroxide. The lithium compound was characterized using SEM and XRD.

Additionally, an electrochemical model was proposed for to predict the behavior and performance of hybrid electrode of LiFePO6/Carbon and the hybrid device constructed with this electrode. This one dimensional model has been based in the transport phenomena, porous electrode theory, double lawyer theory and the electrochemical kinetics.

 The setting of experimental parameters of model was carried out through the electrochemical characterization of LiFePO6 using cyclic voltammetry, EIS, and stationary technics.

The model was validated at small scale in the laboratory using only the hybrid electrode.
A Link Between Lithium Diffusivity, Interplane Distance and Ni Redox State in Ni-Rich Ncm
Authors: Kondrakov Aleksandr O. , Berkes Balázs B. , Geßwein Holger , Sommer Heino , Brezesinski Torsten , Janek Jürgen
Published: February 2020

Both enhanced Li diffusivity and high discharge capacities make Ni-rich LiNi1-x-yCoxMnyO2 (NCM) cathodes attractive for application in high energy density Li-ion batteries with good power [1]. However, further improvement in power density requires a thorough understanding of the mechanisms underlying the Li diffusion kinetics. Here, we investigate changes in Li diffusion coefficient (D
Li) during charging of NCM/Li cells and link the evolution of D
Li to the atomic structure and material resistivity.

Results from galvanostatic intermittent titration technique show that Li diffusivity in NCM cathodes evolves non-monotonically during charge and discharge. The most significant changes are observed in the potential range from 3.6 to 4.0 V with respect to Li/Li+. Electrochemical impedance spectroscopy suggests that the lithium intercalation kinetics is primarily controlled by the charge transfer resistance at the cathode/electrolyte interface, while in operando X-ray diffraction indicates that the spacing along the c-axis increases, which we attribute to an increase of the repulsion between the oxygen slabs in the absence of screening Li. Furthermore, we observe a drastic decrease in the interplane spacing between 4.0 and 4.3 V, and a gradual decrease of the in-plane spacing (a,b-axis) during Li-deintercalation. The latter indicates shortage of the O-Me bonds with oxidation of Ni. Overall, our research data demonstrate that Li diffusion in Ni-rich LiNi1-x-yCoxMnyO2 is strongly controlled by the interplane spacing of the host structure, and the overall kinetics appears to be limited by high interfacial charge transfer resistance at the beginning of charge.

References

[1] Wei, Y.; Zheng, J.; Cui, S.; Song, X.; Su, Y.; Deng, W.; Wu, Z.; Wang, X.; Wang, W.; Rao, M.; Lin, Y.; Wang, C.; Amine, K. & Pan, F. Kinetics Tuning of Li-Ion Diffusion in Layered Li(NixMnyCoz)O2, Journal of the American Chemical Society, 2015, 137, 8364-8367.
Simple Hydrothermal Preparation of High Performance LiMn0.7Fe0.3PO4/C Nano-Particle Cathode Materials
Authors: Li Jiangang , Yao Qiong , Wang Liyuan , He Xiangming , Wang Li
Published: February 2020

Olivine LiFePO4 has been widely used as cathode material in lithium-ion batteries for electric vehicles (EV) due to high safety and long life. Its main drawback is low voltage plateau (3.5V).  Recently, studies of LiMnPO4 have been paid more attention because it possesses the same structure and theoretical capacity as LiFePO4, but higher voltage plateau (4.1V). However, the poor conductivity limits its uses. Some modification methods such as ion-doping, carbon coating etc. have been investigated to improve its electrochemical properties, and the results in many papers indicated that LiMn1-xFexPO4/C (x=0.2~0.5) nano-particle composite cathode materials prepared by hydrothermal method can present promising electrochemical performance. For such method, how to use simple process to achieve LiMn1-xFexPO4/C nano-particles with high crystallization and dispersion is an important issue to be solved urgently at present.

In this work, a simple and high effective hydrothermal preparation process for LiMn0.7Fe0.3PO4/C was proposed. In such process, the synthesis and carbon coating of LiMn0.7Fe0.3PO4 was completed in one-step. The structural and electrochemical properties of as-prepared materials were studied by using XRD, SEM, electrochemical impedance and charge-discharge tests technologies. The carbon sources and surfactant added in the process were optimized.

The results show that when using CTAB as surfactant and glucose as carbon source, one-step process make LiMn0.7Fe0.3PO4/C obtain more uniform coated carbon, more controlled crystal particle growth and dispersion, more excellent electrochemical performance while compared with two-step process including hydrothermal synthesis followed by carbon-coating process. CTAB content exhibits little effect on crystal lattice parameters, structure and coated-carbon amounts of as-prepared materials. However, it displays great impact on the crystal particle size, carbon coating uniformity and particle dispersion. With gradual increase of CTAB content to 2.5g (in 40ml reaction liquid), as-prepared samples show an improved carbon coating uniformity, elevated Li+ diffusion coefficient, reduced electric charge transfer resistance, and remarkable enhanced capacity, rate capability and energy density. It presents a capacity of 143.5 mAh/g at 0.5C and 112.6 mAh/g at 5C, respectively. It is also noticeable that the sample exhibits an energy density of 499.3Wh/kg, 457.8Wh/kg and 349.7Wh/kg at 1C, 2C and 5C rate respectively. In addition, other surfactants that can also be used as carbon sources at the same time were also investigated, and it is found that some surfactant can substitute for CTAB+glucose to further simplify process and lower cost.
Developing a Cheap and Accessible Electrochemical Cell for Operando Neutron Diffraction Investigations of Lithium and Sodium Ion Batteries
Authors: Brant William Robert , Roberts Matthew , Edström Kristina , Gustafsson Torbjörn
Published: February 2020

While the interest and frequency of performing operando neutron diffraction experiments for lithium ion batteries has increased significantly over the past few years, it is still not nearly as popular as operandoX-ray diffraction. A major contributor to this is the high difficulty of constructing an electrochemical cell which balances both electrochemical performance, quality of the obtained diffraction pattern and cost of construction. Up until now most work has been performed on, often complex, custom cells built to target a specific feature such as, fast cycling at the cost of data quality or data quality with high material loading [1-3]. What if, however, a complicated cell was not required? What if commonly used commercial cells could be adapted to obtain a high quality diffraction pattern with minimal effort?

By taking inspiration from operando X-ray diffraction cells based on modified coin cells, we have modified a coin cell to be used for operandoneutron diffraction experiments. The modified cells contain a large quantity of active material (~300-400 mg) to a much smaller quantity of electrolyte (~10-50 μL), separator and lithium metal. The smaller quantity of electrolyte is particularly important as it significantly reduces the cost of the experiment if deuterated electrolyte is employed. Further, despite the large quantity of sample, the cells exhibited favourable electrochemistry when cycled at C/10. Using this cell high quality diffraction data could be obtained (Figure 1).

This contribution will therefore focus on the diffraction results that can be obtained from such a cell by comparing to earlier wound cells. It is anticipated that such a cell design will make neutron diffraction accessible to more research groups and also presents a viable cell design for operandostudies of sodium ion cells.

[1] N. Sharma, X. Guo, G. Du, Z. Guo, J. Wang, Z. Wang, and V. K. Peterson. J. Am. Chem. Soc.134 (2012), 7867

[2] M. Roberts, J. J. Biendicho, S. Hull, P. Beran, T. Gustafsson, G. Svensson and K. Edström. J. Power Sources 226 (2013), 249.

[3] M. Bianchini, J.B. Leriche, J.L. Laborier, L. Gendrin, E. Suard, L. Croguennec, C. Masquelier, J. Electrochem, Soc., 160 (2013) A2176.

Figure 1
Low Dimensional Materials for Lithium-Ion Batteries
Authors: Li Meicheng
Published: February 2020

Along with social progress, the popularity of portable electronic products, the development of new energy such as solar energy and wind energy technology, and the utilization of hybrid electric and electric vehicles all rely heavily on high-performance energy storage devices. Lithium ion batteries are promising storage devices to satisfy these needs due to their advantages of high open circuit voltage, large energy density, long cycle life, no memory effect, less pollution and small self-discharge rate. In fact, the capabilities of electrodes materials show significant effects on the performance of lithium-ion batteries. Nanostructured materials possess reduced sizes, enlarged surfaces, increased boundaries and gaps, which could lead to improved diffusion kinetics, more ion insert channels and release strain for volume changes compared to normal bulk materials. As electrode materials for lithium batteries, nanostructured materials could offer high reversible capacity, fine rate performance and good cycling stability. In this talk, we introduce the design and synthesis of several nanostructured materials, including MoS2-based nanocomposite, NiO porous nanostructure,Hierarchical TiO2 microstructure, and Zn2GeO4/g-C3N4 hybrids, discuss their application for lithium-ion batteries.

 

Reference

Lihua Chu, Meicheng Li, ZiPei Wan, Lei Ding, Dandan Song, Shangyi Dou, Jiewei Chen and Yu Wang. Morphology control and fabrication of multi-shelled NiO spheres by tuning pH value via hydrothermal process.
CrystEngComm
, 2014, 16, 11096

Xiaodan Li, Wei Li, Meicheng Li,* Peng Cui, Dehong Chen, Thomas Gengenbach, Huiyuan Liu, and Guangsheng Song. Glucose-assisted synthesis of the hierarchical TiO2 nanowires @ MoS2 nanosheets nanocomposite and its synergistic lithium storage performance.
Journal of Materials Chemistry A
, 2015, 3:2762-2769 

Lihua Chu, Meicheng Li*, Xiaodan Li, Yu Wang, Zipei Wan, Shangyi Dou, Dandan Song, Yingfeng Li and Bing Jiang. High performance NiO microsphere anode assembled from porous nanosheets for lithium-ion batteries.
RSC Advances
, 2015, 5, 49765 - 49770,    

Peng Cui, Bixia Xie, Xiaodan Li, Meicheng Li,* Yaoyao Li, Yu Wang, Zhuohai Liu, Xin Liu, Jing Huang, Dandan Song, Joseph Michel Mbengue. Anatase/TiO2-B hybrid microspheres constructed by ultrathin nanosheets: facile synthesis and application for fast lithium ion storage.
CrystEngComm
, 2015, 17:7930-7937

Xiaodan Li, Yi Feng, Meicheng Li* , Wei Li, Hao Wei, and Dandan Song. Smart Hybrids of Zn2GeO4 Nanoparticles and Ultrathin g-C3N4 Layers: Synergistic Lithium Storage and Excellent Electrochemical Performance.
Advanced Functional Materials.
2015, 25(44): 6858-6866
Synthesis of Li9V3 (P2O7)3(PO4)2 and Electrochemical Investigation As High Voltage Cathode
Authors: Balasubramanian Prasanth , Mancini Marilena , Axmann Peter , Wohlfahrt-Mehrens Margret
Published: February 2020

Recently, a layered lithium vanadium monodiphosphate Li9V3(P2O7)3(PO4)2[LVPP] has been proposed as a promising cathode material for Li-ion batteries [1, 2, and 3]. Theoretically, extraction of maximum 6 Li ions per formula unit is possible [1, 3]. Thus a theoretical capacity of 173mAhg-1 is achievable through complete oxidation of vanadium from its initial 3+ to 5+ state. Synthesis routes so far reported in literature require either H2rich atmosphere during calcination or use expensive precursors that are air, moisture sensitive. 

Herein we report a low cost and easy two-step solid state synthesis approach to obtain pure LVPP.  A systematic study has been carried out to investigate the influence of crystallite size, carbon coating and working potential window on the specific discharge capacity of Li9V3(P2O7)3(PO4)2 and  is discussed. LVPP, with crystallite size of 40nm and 4% carbon content facilitates the extraction of nearly 5 Li+ ions during the first charge cycle between 2.0-4.8V. Highly reversible specific discharge capacity of 115mAhg-1 could be achieved in the same potential window. When the upper cut-off potential was reduced to 4.6V, a discharge capacity of 75mAhg-1is obtained at charge /discharge rate of 1C.

This contribution presents a facile route to obtain a polyanionic framework material that utilizes more than one electron per transition metal. A much needed boost in capacity with improved cycling stability and rate capability can be achieved with proper tuning of the crystallite size and conductivity.

REFERENCES:

1)      Q.Kuang, J.Xu, Y. Zhao, X.Chen, L.Chen ElectrochimicaActa 56 (2011)  2201–2205

2)      M. Onoda And M. Inagaki  Journal Of The Physical Society Of Japan 80 (2011) 084801

3)      A. Jain, G. Hautier, C. Moore, B. Kang, J. Lee, H. Chen, N. Twu, and G. Ceder Journal of The Electrochemical Society, 159 (5) (2012) A622-A633

ACKNOWLEDMENTS:   This work was supported by the German Federal Ministry of Education and Research (BMBF) in the project Li-EcoSafe (03X4636A).

Figure 1
Hydrothermal Synthesis and Characterization of Co2GeO4/Rgo@C Ternary Composite As Negative Electrodes for Li-Ion Batteries
Authors: Kalai Selvan Ramakrishnan , Yuvaraj Subramani , Kaliyappan Karthikeyan
Published: February 2020

In this present work, pristine Co2GeO4, binary Co2GeO4/reduced graphene oxide (rGO) composite and ternary composite of Co2GeO4/rGO@C is prepared by single step hydrothermal process followed by calcination. The amount of carbon content and rGO is identified through thermogravimetric analysis (TGA). XRD analysis reveals the compound formation of single phase Co2GeO4. TEM and HRTEM images clearly elucidate the presence of ternary phases of Co2GeO4, r-GO and C in the ternary composite. The Galvanostatic charge-discharge (GCD) curve demonstrates that the initial discharge capacity of pristine Co2GeO4, Co2GeO4/rGO and Co2GeO4/rGO@C composite is 1400, 1284 and 1594 mAh g-1 at 50 mAh g-1, respectively. The observed discharge capacity is higher than the theoretical capacity of Co2GeO4 which is due to reduction of organic electrolyte and the formation of solid electrolyte interphase film (SEI). The cycling stability curve shows the specific capacity of 609, 970 and 1180 mAh g-1 for pristine, Co2GeO4/rGO and Co2GeO4/rGO@C composite respectively over 15 cycles which confirms that Co2GeO4/rGO@C composite exhibits the stable and high specific capacity. The rate capability curve and EIS spectrum is carried out for the prepared samples which indicates that Co2GeO4/rGO@C composite shows the better rate capability and good electronic conductivity.
High Rate Performance of a Mn3O4/C Anode Material Prepared By One-Step Pyro-Synthesis for Lithium-Ion Batteries
Authors: Kim Seokhun , Song Jinju , Kim Sungjin , Jo Jeonggeun , Park Sohyun , Lee Jun , Kim Jaekook
Published: February 2020

In response to the ever-increasing global demand for electronic devices, Lithium-ion batteries have taken an important place in meeting this demand since they provide high voltage, high energy density, and are light weight. Nanostructured binary metal oxides (BMOs) which exhibit high theoretical capacity as a result of a conversion reaction. Among the BMOs, the manganese-based oxide hausmannite (Mn3O4) has attracted much attention due to it being low –cost and environmentally benign. A nanostructured Mn3O4/C electrode was prepared by a one-step polyol-assisted pyro-synthesis without any post-heat treatments. The as-prepared Mn3O4/C revealed nanostructured morphology comprised of secondary aggregates formed from carbon-coated primary particles of average diameters ranging between 20 and 40 nm, as evidenced from the electron microscopy studies. The N2 adsorption studies reveal a hierarchical porous feature in the nanostructured electrode. The nanostructured morphology appears to be related to the present rapid combustion strategy. The nanostructured porous Mn3O4/C electrode demonstrated impressive electrode properties with reversible capacities of 666 mAh/g at a current density of 33 mA/g, good capacity retentions (1141 mAh/g with 100% Coulombic efficiencies at the 100th cycle), and rate capabilities (307 and 202 mAh/g at 528 and 1056 mA/g, respectively) when tested as an anode for lithium-ion battery applications.