bluuebunny/crossref_metadata_2025_split huggingface dataset:
Using Computer Simulations to Understand and Predict the Properties of Paradigmatic Lithium-Ion Storage Materials
Authors: Otero Manuel , Urquiza Laura , Chauque Susana , Gavilan Maximiliano , Perassi Eduardo , Velez Patricio , Oviedo Oscar Alejandro , Cámara Osvaldo Raúl , Luque Guillermina , Oliva Fabiana Yolanda , Barraco Daniel E , Franco Alejandro A. , Leiva Ezequiel Pedro Marcos 
Published: February 2020

In terms of sustainable development and environmental issues, the use of efficient storage systems is an increasingly critical point. The world has undergone a great technological revolution in the past 20 years led by lithium ion batteries, due to their high energy density. However, in order to meet the energy demand of our modern life, a new generation of lithium batteries, more powerful, efficient and cheaper, is desirable. Depending on the problem to be addressed, it is useful to model the system at different scales. For example, while first-principles calculations may be useful to predict equilibrium potentials, semiempirical potentials along with molecular dynamics or Monte Carlo simulations may be applied to understand collective phenomena. In the present work we show in
terms accessible to experimentalists
how the use of different simulations tools may be helpful to analyze different aspects of lithium storage materials. The topics to be addressed in the present work are:

Use of first- principles calculations to optimize the stability of Si-Graphite nanostructures.

Application of Monte Carlo simulations to get thermodynamic information on the storage of Li ions into graphite.

Optimization of composites using coarse-grained models.
Porous Si/C Composite Anode Materials for Lithium Ion Batteries
Authors: Fan Li-Zhen , Wang Mingshan 
Published: February 2020

Among all the anode materials, silicon is one of the most attractive anode materials for lithium-ion batteries because of its highest capacity of 4200 mAh g-1, satisfactory voltage window for lithium insertion and extraction (<0.5 V vs. Li/Li+), high safety and low cost. However, the practical utilization of Si as anode material is hindered by its huge volume changes (300%) induced by the lithium-ion insertion and extraction processes, culminating in the pulverization of electrode structure as well as the poor cycling performance. In addition, the low electrical conductivity of pristine Si and the difficulty in the formation of stable solid-electrolyte interface (SEI) films have also restrained the commercialization of Si anode material. Here we report a series of silicon based composites [1-10], such as self-supporting grapheme/Si film, three dimensional porous carbon/silicon composites, three dimensional silicon/TiOx/carbon framework, etc, aiming at solving the problems of current silicon anode materials. Those porous silicon based anode materials have demonstrated to be effective in maintaining good electronic contact among particles and accommodating the mechanical stresses experienced by the huge volume change of active silicon associated with Li insertion/extraction processes.
References
[1] M.S. Wang, Y. Song, W.L. Song, L.-Z. Fan*, ChemElectroChem. 1(2014) 2124-2130.
[2] M.S. Wang, L.Z. Fan*, M. Huang, J.H. Li, X.H. Qu, J Power Sources. 219(2012) 29-35.
[3] M.S. Wang, W.L. Song, J. Wang, L.Z.Fan*, Carbon. 82(2015) 337-345.
[4] M.S. Wang, W.L.Song, L.Z.Fan*, J. Mater. Chem. A, 3(2015) 12709-12717.
[5] H.C. Tao, M. Huang, L.-Z. Fan*, X.H. Qu. Electrochim. Acta, 2013, 89: 394-399.
[6] H.C. Tao, L-Z Fan*, Y.F. Mei, X.H. Qu. Electrochem. Comm., 2011, 13: 1332-1335.
[7] H.C. Tao, M. Huang, L.-Z. Fan*, X.H. Qu. Solid State Ionics, 2012, 220: 1-6.
[8] H.C. Tao, L.-Z. Fan*, W.-L. Song, M. Wu, X.B. He, X.H. Qu. Nanoscale, 2014, 6 (6): 3138-3142.
[9] H.C. Tao, M. Huang, L.-Z. Fan*, X.H. Qu. Electrochim. Acta, 2013, 89: 394-399.
[10] H.C. Tao, M. Huang, L.-Z. Fan*, X.H. Qu. Solid State Ionics, 2012, 220: 1-6.

Figure 1
In-Situ Solid State NMR for Characterizing Battery Materials
Authors: Lorie Lopez Jose L. , Co Anne C. , Grandinetti Philip J. 
Published: February 2020

The demand for inherently safe, large capacity, high-rate capability energy storage has led to the investigation of a class of metallic and semi-metallic elements that form stable intermetallics with lithium, providing Li+ storage capacities of three to ten times that of today’s lithium-ion batteries. Unfortunately, such high capacity intermetallic anodes undergo structural transformations from crystalline to amorphous states with large volume expansions upon intercalation, changing the anode's microstructure and local chemical environments, which lead to reduced capacity. Because of their amorphous nature, the atomic-level structures of the intermetallic are not amenable to study by conventional diffraction techniques.
Solid-state nuclear magnetic resonance (NMR) spectroscopy is an ideal technique to probe amorphous materials and understand how kinetically driven compositional changes affect the material microstructure and the local chemical environment. We have measured the 7Li and 119Sn NMR spectra of electrochemically lithiated tin ex-situ and have identified a number of different lithium environments. Furthermore, we have measured in-situ 7Li NMR spectra as a function of lithiation and de-lithiation of different materials, including graphitic carbon, silicon, and tin. We will discuss the findings and their implications for the design of various nanostructured intermetallic anodes.
Cycle Stability of Silicon Nanoparticles Coated with Nitrogen-Doped Carbon Layer for Lithium Ion Battery Anode
Authors: Cho chae Ryong , Choi hun Seok , Pham-Cong De , Cho Jin Hyuk 
Published: February 2020

Silicon is one of the promising candidate materials for lithium ion anode. This anode has a theoretical specific capacity of 4200 mAh/g which is about 10 times higher than the commercial graphite anode. However, Si anode has a short cycle life during the lithiation-delithiation process because of its volume expansion of up to 400%. In this study, to improve the cycle stability of Si anode through the control of volume expansion, we fabricated the single crystal Si nanoparticles (dia. ~50 nm) by using laser photo-pyrolysis technique and then the nitrogen-doped carbon layer was coated on them by using FeCl3 source. The electrochemical performance of samples according to the amount of FeCl3(0.3-2g) was investigated. The capacity retention of the Si nanoparticle with N-doped carbon layer (Si@NC) sample was approximately 74.9% at 1C after 300 cycles. Surface chemical states for elements of the anode materials according to the thickness of nitrogen-dpoed carbon layer are mentioned in detail. The effect of the coating layer is very strong to prevent Si volume change, so our experimental result for cycling test could be expected.
Surface Modifications of LiFePO4 Electrode for Aqueous Lithium Ion Batteries
Authors: Tron Artur V. , Kim Jaemin , Ryu Ji Heon , Choi Wonchang , Mun Junyoung 
Published: February 2020

1. Introduction

The rechargeable lithium-ion batteries (LIBs) with organic electrolytes have become the alternative energy supply for portable equipments, consumer electronic devices and high power applications such as electric vehicles and power storage for renewable energy [1]. However, their safety issue and high cost limit their application for large scale energy storage because LIBs use the flammable and expensive organic electrolytes. An aqueous rechargeable lithium battery (ARLB) was first reported by Dahn et al., which has advantages such as safety and low cost [2]. However, its practical application was hindered due to its poor cycling and not good rate capability. Here, we have shown that surface modifications of LiFePO4 showed a much better rate capability in aqueous electrolyte than pristine LiFePO4.

2. Results and discussion

The influence of the surface coating on the electrochemical properties of LiFePO4 cathode in aqueous electrolyte solution was investigated by systematic electrochemical and instrumental analyses. The electrochemical performance of pristine LiFePO4 and coated LiFePO4 is presented in Fig. 1. Despite the high ionic conductivity of the aqueous electrolyte (1 M Li2SO4 in water), the pristine LiFePO4 did not show the high rate capabilities. In detail, the pristine LiFePO4 and coated LiFePO4 in aqueous electrolyte, which can deliver the initial discharge capacity of 127.5 and 132.1 mAh g−1 at 1 C, respectively. The pristine LiFePO4 and coated LiFePO4 have still the discharge capacity of 108.9 and 122.7 mAh g−1 after 100 cycles. Based on these results, it is confirmed that the resistance from the surface failure mode of LiFePO4 could be a main hurdle for cycle decaying especially in the aqueous electrolyte. After the surface modification of the electrochemically stable inorganic species, the rate capability and the cycle life are further improved. This coating enhance the surface stability to the aqueous solution and presents very promising cycle and rate capabilities for the development of ARLBs. Furthermore, they are investigated in detail by using XPS, SEM and TEM analyses.

Acknowledgments

This research was supported by the Post-Doctor Research Program (2014-2015) through the Incheon National University (INU) and the Basic Science Research Program through the National Research Foundation of Korea (NRF), funded by the Ministry of Science, ICT & Future Planning (NRF-2014R1A1A1038248).

Reference

[1] M.R. Palacin, Recent advances in rechargeable battery materials: a chemist’s perspective, Chem. Soc. Rev. 38 (2009) 2565-2575.
[2] W. Li, J.R. Dahn, D.S. Wainwright, Rechargeable Lithium Batteries with Aqueous Electrolytes, Science 264 (1994) 1115-1118.

Fig. 1. The cycling performance of pristine LiFePO4 and coated LiFePO4 in aqueous solution.

Figure 1
Following Synthesis and Structure of Spinel and Layered Compounds Using Neutron Powder Diffraction
Authors: Huq Ashfia 
Published: February 2020

Sensitivity to light elements in the presence of heavier elements makes neutron diffraction an ideal tool to study oxides, hydrides and compounds containing Li. As a result neutron crystallography has been very successfully used to elucidate structures of electrode and electrolyte materials used in Li-ion battery materials. In this presentation, I will speak about several of these electrode systems where structure helped understand the electrochemical properties and synthesis mechanism.
Structural and Chemical Characterization of Li-Ion Batteries
Authors: Romano Linda , Neuburger Monica , Tsung Lancy , Schneider Yanika , Pajcini Vasil , Robie Steve , Wang Xinwei 
Published: February 2020

Lithium ion batteries have improved rapidly in the last 10 years to become the main power source in portable electronics, telecommunications, and large capacity applications such as in electric vehicles (EV). Ongoing improvements in characterization techniques must also meet industry, regulatory and consumer needs as battery manufacturers and end-users demand higher battery efficiencies, lower cost, and most importantly, safety.
At Evans Analytical Group (EAG, Inc.), we provide a suite of techniques suitable for both the structural and chemical analysis of Li-ion batteries. Both scanning and transmission electron microscopy (SEM and TEM) are used to provide the thickness and microstructure of the various layers in the battery. Ion milling techniques are used to preserve the integrity of the sample to assure an accurate representation of the original state of the battery materials. This is essential in order to properly understand process development or battery failures. TEM combined with X-Ray Diffraction (XRD) can also be used to analyze the phase transformations associated with the diffusion of Li-ions. Additionally, the thickness of the thin SEI layer caused by electrode-electrolyte interfacial reactions can only be visualized by TEM.
Degradation mechanisms of the battery materials can be analyzed with surface analysis techniques such as X-ray photoelectron spectroscopy (XPS) to detect chemical state information and gas chromatography (GCMS) techniques to detect volatile components that can lead to swelling of the battery. These techniques along with Raman and infrared spectroscopy (FTIR), and Glow Discharge Mass Spectrometry (GDMS) can detect the organic and inorganic species present in the battery, including any impurities that may be present. GDMS is commonly used for purity certification of cathode materials such as LiCoO2, LiFePO4, and LiCoMnNiOx
.Inductively coupled optical emission techniques (ICP-OES) can be used to determine the Li/metal ratio to within a 1% uncertainty, which is essential for tuning the cycling stability of Li-ion batteries.
In this presentation we will demonstrate the multi-disciplinary approach of using these various techniques and the importance of proper sample preparation for accurate analyses of Li-ion batteries. This approach enhances the value of the information obtained and can accelerate product development.
Simplification in Processing Lithium-Iron-Phosphate-Powders By Design of Secondary Agglomerates
Authors: Pettinger Karl-Heinz 
Published: February 2020

Problems of submicron active powders are their big surfaces, such as lithium iron phosphate. Owed to this the coating process requires a lot of solvent. Result is a low solid content, respectively a high slurry viscosity. Therefore special technology and big efforts are necessary for the industrial mass production to process such submicron lithium iron phosphate powders. To overcome the handling difficulties of the submicron powder, spherical secondary agglomerates have been synthesized from those submicron particles. These agglomerates have the size of standard oxide cathode powders (2 µm – 30 µm).
The tap density of the agglomerates could be reduced and the surface area is much lower (~30%). Due to this fact, high solid contents can be realized in the slurry. This leads to reduced amounts of necessary solvent within the coating process. Advantages for the processability are in summary: higher tap density, reduced surface area, reduced solvent demand, greatly simplified slurry dispersing processes and high areal loadings of the electrodes.
The synthesis of secondary agglomerates with lithium iron phosphate allows much better processability and a higher areal loading in the electrodes by preservation of the advantages of the sub-micron materials.
This work compares electrodes of the newly developed lithium iron phosphate secondary agglomerates with the primary submicron particles in respect to their areal loading, high rate capability and processability. Lithium iron phosphate has a very good rate capability and excellent safety features. The submicron powder has disadvantages that lead to a highly increased effort in processing and a limited areal loading. With the design of spherical agglomerates those disadvantages could be eliminated. Moreover all the advantages of the material itself could be combined with better processability. Processability and the full cell performance of primary particles with those of secondary agglomerates from lithium iron phosphate are compared.
Electrodes prepared from the secondary agglomerates make it even easier to reach higher areal loading ( >2 mAh/cm² or 13 g/cm²). Additionally the electrochemical performance of the primary particles could be enhanced. The increased tap density and the smaller surface area enhance processability. Reduced amount of solvent enable slurries with improved rheology for established dispersing and coating processes.
The design of secondary agglomerates leads to much better processable cathode powders and electrodes with retained or improved electrochemical properties of such prepared with the original powder material.

Figure 1
Effects of Adsorbed Water on Nano Silicon for Lithium-Ion Battery
Authors: Yoshida Shuhei , Masuo Yuta , Shibata Daisuke , Haruta Masakazu , Doi Takayuki , Inaba Minoru 
Published: February 2020

Silicon has been developed as a promising anode in the next generation lithium-ion batteries due to its high gravimetric capacity density of 3580mAh g−1 at room temperature. However, the lithiation and delithiation reactions are accompanied by large volume changes, resulting in the fracture and pulverization of Si particles and leading to the failure of electrical contacts and poor cycleability. To suppress the physical stress due to its large volume change, we have reported Si Leaf Powder® (Si-LP, Oike & Co., Ltd.), which is amorphous Si nano-flake powder exhibited a good cycleability.1-3 Another serious problem for Si-LP anode such as a large irreversible capacity in the initial and during cycleability remain to be solved for practical use. In previous studies, we have reported Li pre-doping technique using direct contact method with Li foil and Li-naphthalene complex solutions, which completely compensated a initail large irreversible capacity. 4-5Unfortunately, irreversible capacity was continually generated during cycleability and coulombic efficiency was hovered at 97.9 % even after 10 cycle, where part of charging Li was considered to be consumed for the decomposition of electrolyte solution as solid electrolyte interface (SEI).
In this study, the effects of adsorbed water on nanolized amorphous silicon and its electrodes were investigated by meas of analysis of Karl-Fischer method and in-situgas generation measurement under different drying condition. In addition, their electrochemical properties including the charge and discharge characteristics were carried out to elucidate the effects of containing water.
1,743 ppm of water in nano-flake amorphous silicon powder were detected at 250°C Karl-Fischer method even after 1 hour drying at 120°C under 3Pa. This result indicated that nano-flake amorphous silicon were strongly bonded with water and the water was not easy to remove in electrode drying process, which were usually conducted around 100°C in practical CMC/SBR binder electrode. In coparision with graphite electrode, more than twenty times of adsorbed water were observed in nano-flake amorphous silicon electrodes and considerred to track inside the cell, leading to low coulombic efficiency not only initial but during cycleability. Actually, H2 gas generation was increased and initial coulombic efficiency was enhanced after dried at 180°C under 3Pa. In addition, remarkable coulombic efficiency improvement of 99.9 % (2140 mAh g−
1) was observed after 10 cycles. The results of this study show that nanoized silicon strongly adsorbed water , which continuously caused the decomposition of electrolyte solution.
References: [1] K. Nakai et al., Electrochemistry, 78 (2010) 438.; [2] M. Saito et al., J. Power Sorces, 196 (2011) 6637.; [3] M. Saito et al., Solid State Ionics, 225 (2012) 506.; [4] T. Okubo et al., Solid State Ionics, 262 (2014) 39.; [5] S. Yoshida et al., Electrochemistry, 83 (2015), 843.
Investigation of Electrochemically Driven Li-Si Phase Formation and Li Diffusion
Authors: Lyons Daniel Joseph , Co Anne C. 
Published: February 2020

We have carried out extensive ultra-slow scan cyclic voltammetry on nanoscale silicon to elucidate the electrochemical formation of Li-Si alloys and determine diffusion coefficients. Our results suggest a multi-cycle permanent conversion of bare silicon to the first Li-Si phase, Li12Si7, as the least lithiated state. This constitutes a significant part of the capacity fade observed in silicon electrodes. In addition we observe multiple diffusion constants in long-term current transients using established models from literature. The electrochemically obtained data will be complemented by a neutron based technique previously developed in our group, referred to as neutron depth profiling, to elucidate the Li distribution and potential trapping or slow kinetics of Li12Si7 within the material resulting in capacity fade.
Redox Activity of Li3VF6 and Similar Compounds at High Voltages
Authors: Plews Michael Rhys , Krakra Jenine , Neto Wanderlino , Aslam Mohammed , Samreen Maseera , Yi Tanghong , Cabana Jordi 
Published: February 2020

Increased energy density is required for rechargeable batteries to keep up with the consumer demand for electronic devices, electric vehicles, and smart grids. Current lithium ion battery technology utilizes cathodes with high voltage and capacity against a carbon anode, shuttling Li ions back and forth on charge and discharge in a non-aqueous electrolyte. No new commercially viable cathodes with greater capacity than those identified by Goodenough and co-workers1 have been yet found, with no real increase in capacity over the original LiCoO2 composition since 1980. Options to increase energy density in Li-ion batteries can be summarized by increasing the voltage or lowering the molar mass of the active material in the cathode. Families of compounds that have yet to be investigated are scarce, however one such family are those containing fluorides. By introducing a more electronegative anion, higher oxidation states of transition metals can be stabilized which opens up the opportunity of higher redox potentials as well as the possibility of more than one Li+ ion deintercalation per transition metal; a phenomenon yet to be observed in Li-ion batteries. Lithium-transition metal-fluorides have potential as candidates for high voltage, low molar mass cathode materials, resulting in high energy density.
Thus far, it has only been shown that lithium intercalation into Li3MF6 (MIII to MII) structures has been possible2,3, while the elusive reversible deintercalation (MIII to MIV) has not been achieved. Our preliminary studies show that in certain conditions, reversible deintercalation of these family of compounds is possible providing the synthetic methods are carefully controlled. Previously reported synthetic routes for these class of materials utilized aqueous precipitation methods and sol-gel processing methods involving water. It is already a well-established principle that at high voltages, run-away reactions between the electrolyte and water can occur. By synthesizing these materials in a completely air and water free environment, we have observed evidence of reversible oxidation and changes in crystals structure of Li3VF6 through electrochemical analysis at 4.4V vs Li. Changes in the oxidation state of the central transition metal were confirmed by hard x-ray absorption spectroscopy and changes in the crystal structure were shown using high resolution x-ray diffraction. We are currently investigating this family of materials with other transition metals and anticipate these compounds will show similar results.
These promising results have given hope to redox chemistry at much higher operating voltages than has been previously observed for fluoride compounds.
1. K. Mizushima, P. C. Jones, P. J. Wiseman, and J. B. Goodenough, Mater. Res. Bull., 15, 783–789 (1980).
2. A. Basa, E. Gonzalo, A. Kuhn, and F. García-Alvarado, J. Power Sources, 207, 160–165 (2012).
3. G. Lieser et al., J. Power Sources, 294, 444–451 (2015).