bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation of the Electrochemical Properties of Copper Hydroxide and Related Copper Oxides in Sodium-Ion Batteries
Authors: Mamiya Mikito , Akimoto Junji 
Published: February 2020

Recently, CuO shows high charge and discharge capacity in Na-ion battery. The number of electrode materials for Na-ion battery is much less than that for Li-ion battery. Copper oxide and related materials are candidate for the high potential electrode materials for Na-ion battery. The theoretical capacity of CuO is 674 mAh g-1. When the charge-discharge reaction evaluated the range between 0 and 3.0 V, the discharge capacity shows 600 mAh g-1 at 1st. However, the discharge capacity in 2nd cycle is decreased to near 300 mAh g-1. The low cycle performance is one of the week points. In order to improve the cycle performance, we evaluate the properties in various voltage ranges and research the best performance condition. The charge-discharge reaction evaluated using a 2032 type coin cells. The working electrode was prepared by mixing the samples, acetylene black (AB) and plytetrafluoroethylene (PTFE) in a 70:20:10 weight ratio. Na metal was used as a counter electrode. The 1M NaClO4 in EC:DMC(1:1) solution was used as the electrolyte. The current density was 10 mA g-1. When we set it between 1.0 and 4.0 V, which is 1.0 V higher than before, CuO shows reversible charge-discharge reaction up to 20 cycles. The maximum discharge capacity is nearly 150 mAh g-1. Cu2O was also evaluated the properties, however the material did not show reversible reaction. The maximum discharge capacity is below 10 mAh g-1. Cu(OH)2 is a novel material as an electrode of Na-ion battery. The charge-discharge reaction was also evaluated. Figure 1 shows the charge-discharge profiles up to 10 cycles. The maximum discharge capacity is 247 mAh g-1. There is a plateau around 1.3 V, which is corresponded to the redox reaction of Cu2+ to Cu+ (vs Na+/Na). When the voltage range expands to 0 V, the redox reaction of Cu+ to Cu would increase the capacities. However, the redox reaction makes disadvantage effect of the cycle performance. Figure 2 shows the cycling performances of Cu(OH)2 in the voltage range of 1.0 to 4.0 V. The reversible charge-discharge reaction is observed, although the discharge capacities above 200 mAh g-1 show only first 4 cycles. The cycling performance is not good. We are investigating the best matching of the measurement ranges and the electrolytes. Furthermore, we develop an in-situ measurement of X-ray diffraction and charge-discharge reaction. It will clear the mechanism of the reaction from the view of changing crystal structures.

Figure 1
Sulphur Substitution As an Effective Way to Promote the Structural and Electrochemical Performance of the LiMn2O4 Cathode Material
Authors: Bakierska Monika , Molenda Marcin , Dziembaj Roman 
Published: February 2020

The lithium-ion batteries are considered as the most dominant technology in the field of energy storage due to their high energy density [1]. Since they were introduced into market, the application targets have expanded from small portable devices to large-scale applications including hybrid electric vehicles (HEV), electric vehicles (EV) and stationary energy storage systems [2,3]. Lithium manganese oxide spinel has been recognized as a potential alternative cathode material. In comparison with LiCoO2, LiNiO2 and related systems, LiMn2O4 spinel possesses many advantages, e.g. high abundance, non-toxicity, low cost and great safety characteristics [4]. Nevertheless, it is well known that stoichiometric lithium manganese spinel suffers from significant capacity fade during the electrochemical cycling which is generally attributed to structural changes caused by Jahn Teller distortion of Mn3+ ions [5]. One of the various approaches to achieve better structural stability and hence, improve capacity retention is modification of oxygen sublattice in the LiMn2O4spinel by partial substitution with sulphur [6].
The aim of this work was to investigate how sulphur substitution affect the structural and electrochemical properties of LiMn2O4-ySyspinel materials.
Nanosized LiMn2O4-ySy (y = 0 or 0.01) spinel materials were obtained by a modified sol-gel method based on the hydrolysis and condensation processes. The prepared Li-Mn-O-S spinel systems were investigated with regard to the physicochemical properties using X-ray powder diffraction (XRD), elemental analysis (EA), nuclear magnetic resonance (NMR), low-temperature nitrogen adsorption-desorption measurements (N2-BET), differential scanning calorimetry (DSC) and electrical conductivity (EC) studies. The electrochemical performance of Li/Li+/LiMn2O4-ySycells was examined by galvanostatic charge/discharge tests (CELL TEST) and electrochemical impedance spectroscopy (EIS).
It was established that the introduction of a small amount of sulphur leads to the stabilization of the spinel structure and consequently, the enhancement of the cycling behavior what confirmed that sulphur substitution is an efficient way to advance the structural and electrochemical properties of the LiMn2O4spinel.
References:
[1] J. M. Tarascon, M. Armand, Nature 414 (2001) 359-367.
[2] K. Amine, J. Liu, I. Belharouak, S. H. Kang, I. Bloom, D. Vissers, G. Henriksen, Journal of Power Sources 146 (2005) 111-115.
[3] R. Mukherjee, R. Krishnan, T. M. Lu, N. Koratkar, Nano Energy 1 (2012) 518-533.
[4] J. W. Fergus, Journal of Power Sources 195 (2010) 939-954.
[5] L. Yang, M. Takahashi, B. Wang, Electrochimica Acta 51 (2006) 3228-3234.
[6] M. Molenda, R. Dziembaj, D. Majda, M. Dudek, Solid State Ionics 176 (2005) 1705-1709.
A Novel CNT Anode Material for Li Battery Applications
Authors: Riehl Bill , Riehl Bonnie , Banks Craig 
Published: February 2020

Carbon nanotubes hold excellent promise for lithium based energy storage and conversion applications. The use of typical nanophase sp2 carbon as a host material has two principal disadvantages, chief of which is the substantial presence of electrochemical impurities and low lithium storage ability when compared with metallic lithium. A process is shown that produces electrochemically clean, high defect rate carbon nanotubes through the corrosion of silicon carbide fibers to produce a low internal resistance, high activity anode material for Li battery applications. This material is shown to be superior to conventional chemical vapor deposition grown CNTs electrochemically and physically. Residual material present in carbide derived CNTs are electrochemically inert carbides and oxides. The resulting CNT bundles are more consistent in chirality, as well as defect rate and physical dimension than the CVD grown counterparts.
Under optimal conditions Li intercalates into graphitic material in the form of LiC6, which leads to a specific capacity reduction from 3860 mAh/g for metallic Li to 372 mAh/g for the graphitic anodes. We describe a process, carbothermal carbide conversion, for the production of a uniquely valuable carbon nanotube material for electrochemical applications comprised of bundles of SWCNTs of high defect rate. As carbide conversion nanotubes form, the CNTs aggregate into bundles which consist of single-wall nanotubes held together by van der Waals forces roughly equivalent to graphitic sheet spacing, approximately 5 angstrom. These ropes display increased energy storage capabilities as Li ions can intercalate both into the channels between the nanotubes, and into the interior of the nanotubes themselves. This gives an anode stoichiometry of approximately LiC2, which is considerably higher than the value of conventional Li-graphite anodes. Studies have shown that the entry of Li ions preferentially enter through defects such as kinks or open ends of nanotubes. We show higher edge plane character of carbide derived CNTs via Raman spectroscopy, transmission electron microscopy and electrochemical deposition of nickel.

Figure 1
Microwave-Assisted Synthesis of Tin Sulfide/Reduced Graphene Oxide Nanocomposites As Anode Material for High-Performance Lithium-Ion Batteries
Authors: Lin Jeng-Yu , Ho Hsin-Ping 
Published: February 2020

Rechargeable Lithium ion batteries (LIBs), as a great promise power source for next generation electric vehicles such as electric vehicles (EVs). Demands for batteries with higher energy density, better cycle performance, lower cost and more safety are increasing. Graphite is mostly used as anode material for the commercial Lithium ion batteries with the theoretical specific capacity 372 mAh g-1 only. However, in order to overcome the lower capacity problem, many alternatives as anode materials are concerned including metals or metal sulfides.
Recently, tin-based materials (e.g. Sn, SnO2, SnS) have been widely studied as anode materials because they have relatively high theoretical capacities, less toxic and low cost. In particular, tin sulfides has such as high theoretical capacity 782 mAhg1.However, the great volume expansion and the agglomeration of particles for the tin sulfides during the charge/discharge process could possibly result in pulverization of the electrode and thus to lead to rapid decrease in capacity and poor cycle life.
Graphene or reduced graphene oxide (RGO), as one of the highly potential materials in lithium-ion batteries, is also used to be decorated with metal oxides or metal sulfides due to their high specific surface area, excellent electronic conductivity and porous structure. Therefore, an improved electrochemical performance can be achieved. More recently. Lots works have demonstrated that the incorporation of graphene within tin sulfide-graphene nanocomposites can provide a large area contact for tin sulfide particles and inhibit the volume change of tin sulfides, thus enhancing the electrochemical performance of tin sulfide-graphene nanocomposites.
Thus, in this work, SnS/RGO nanocomposites was synthesized via a facile microwave-assisted method. The physical and electrochemical properties of the as-prepared nanocomposites were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis, cyclic voltammetry, galvanostatic charge/discharge tests and electrochemical impedance analysis. Indeed, the SnS nanoparticles were successfully decorated on the surface of RGO, and the resultant SnS/RGO nanocomposite demonstrated an improved electrochemical performance because the incorporation of RGO provided a large area contact for SnS nanoparticles and inhibited the volume change of SnS during charge/discharge process.
Li-Ion Nanotubes for Li-Ion and Li-Sulphur Batteries
Authors: Yokota Nanami , Alfredsson Maria 
Published: February 2020

Rechargeable lithium-ion batteries are considered to be the most promising energy storage due to their long cycle life and high specific capacity.[i] However, existing lithium-ion batteries use graphite as anode material and this is not efficient enough to reach market level to be employed in vehicles. There are still some challenges to develop more in anode material to enhance their performance to meet the requirements for efficient energy storage. [ii] Silicon has been regarded as the most promising candidate to replace graphite anode material due to its excellent merits in high theoretical electrochemical capacity. It is safe to use in high-power applications due to its low discharge potential. [iii] However, the commercial application of Silicon in the battery is still not progressed due to severe mechanical damage because of volume expansion and contraction of Si electrodes during cycling operation. This could cause pulverisation and loss of capacity[iv] An effective way to solve this problem is the employment of nanostructure which are capable of minimising the volume change due to small size and available surrounding free space.[v]
The aim is to synthesise and lithiate silicon nanotubes, then employ the lithiated nanotubes as an anode material in both Li-ion as well as Li-sulphur batteries. This would improve the electrochemical performance by enhancing the cycling performance and higher reversible specific capacity may be achieved.

[i] M.Rosa Palacin, Chemical Society Reviews, 2009, 38, 2565-2575.
[ii] S. Flandrois, B.Simon, Carbon, 1999, 37, 165-180.
[iii] J. Cho, Journal of Materials Chemistry, 2010, 20, 4009-4014.
[iv] D. Billaud, E. Mcrae and A. Herold, Mater. Res. Bull., 1979, 14, 857–864.
[v] J. Bae, J. Solid State Chemistry, 2011, 184, 1749–1755.
Towards High-Capacity Silicon Anodes for Lithium-Ion Batteries: On the Influence of Loading and Surface Coating on the Cyclability
Authors: Breitung Ben , Schneider Artur , Baumann Roelf-Peter , Sommer Heino , Brezesinski Torsten , Janek Jürgen 
Published: February 2020

The development of efficient energy storage systems is of great importance in view of the increasing demand in electrical energy both for stationary and mobile applications. Silicon (Si) is an abundant and nontoxic material and provides one of the highest theoretical specific capacities (approx. 4000 mAh/g) of all known anode active materials. However, severe mechanical stresses, low coulombic efficiencies and irreversible capacity losses during cycling of silicon anodes are critical issues that need to be addressed.
For “real world” applications, it is indispensable to increase the gravimetric and volumetric energy densities of Li-ion batteries (e.g., by tailoring the areal loading of electrodes). Low active material loadings lead to high rate capability and good cyclability but result in low practical energy densities (and areal capacities). In this work, we show that systematic investigations of Si-based anodes with different silicon loadings help finding the optimum between cycling stability and areal capacity. Furthermore, we describe a straightforward pyrolysis process that allows for carbon encapsulation of silicon nanoparticles, which thus enhances the electrode stability, including rate capability and capacity retention. Batteries using the silicon/carbon nanocomposite demonstrate specific capacities of >2000 mAh/g and areal capacities of approx. 2 mAh/cm² over 200 cycles. The different materials employed were analyzed in detail via TEM, REM, Raman- and IR-spectroscopy, and galvanostatic charge/discharge measurements. In addition, we present results on the volume changes (cell “breathing”) and SEI formation upon cycling from in operando AFM measurements.
Studies of Anomalous Diffusion in Composite Silicon Anodes
Authors: Lain Michael J , Beattie Shane D , Loveridge Melanie J , Bhagat Rohit , Dashwood Richard 
Published: February 2020

1. Introduction

The diffusion coefficient is an important parameter of active materials for lithium ion batteries, particularly in higher rate applications like electric vehicles. It is useful to know the diffusion coefficient as a function of state of charge, and other parameters like temperature. Silicon has a very high lithiation capacity (3579 mA hr g-1), but a correspondingly large expansion when fully lithiated (> 270 %). On the first charge, crystalline silicon is converted to amorphous LixSi, and then to crystalline Li15Si4 at full lithiation. The diffusion coefficient in a-LixSi will have an important influence on the movement of these two phase boundaries, which in turn will impact upon the performance and operating life of the electrode. The two main techniques used to measure diffusion coefficients are a. c. impedance, via the Warburg coefficient, and galvanostatic intermittent titration technique (GITT). This report describes the use of both of these methods on composite silicon anodes.
2. Results

Electrodes were prepared using 3 µm silicon powder, with partially neutralised poly acrylic acid as binder and conductive carbon. Following a slow formation cycle (C/20), impedance spectra were recorded in two electrode half cells, at different states of charge. Figure 1 shows typical results at lithiation capacities of 300, 600, 900 and 1200 mA hr g-1. The data was fitted to equivalent circuits, with a series resistance, two resistor // CPE parallel combinations, and a low frequency constant phase element (CPE) tail. Apart from the fully delithiated anode, the tail was always at a much steeper angle than the standard Warburg value of 45o (power term = 0.5). Figure 2 shows plots of the fitted power term {n in Z = (iw)-n C-1}, at three different states of charge, during cycling.
3. Discussion

One explanation for the steeper gradient is that the diffusion is anomalous or non-Fickian [1]. This can occur for charge carrier movement in amorphous solids, like LixSi. After each hop, the charge carrier can wait “for a period drawn from a broad power law distribution” [1], reducing the overall rate of diffusion. Interestingly, a recent theoretical study has calculated a wide range of activation energies for lithium hopping in amorphous silicon (0.1 to 2.4 eV [2]). The difference in the power term at 600 mA hr g-1 during lithiation and delithiation implies a structural hysteresis, which may match the voltage hysteresis observed with silicon anodes.
Further results, including GITT experimental data and analysis, will be presented at the conference.
References

[1] J. Electroanal. Chem. 499 (2001) p. 112 J. Bisquert & A. Compte
[2] J. Phys. Chem. C 116 (2012) p. 22212 G. A. Tritsaris, K. Zhao, O. U. Okeke & E. Kaxiras

Figure 1
Structural Defects and the Impact of Battery Ageing - How Sensitive Are Entropy Profile Measurements, and What Do They Show?
Authors: Schlueter Steffen , Osswald Patrick J , Hoster Harry Ernst , Ghasemi Shahnaz , Maher Kenza , Yazami Rachid 
Published: February 2020

We report on entropy profile measurements at lithium ion full and half cells.1 Those profiles are derived from voltage responses on temperature variations for various states of charge. For LiCoO2 cathodes, measured in half cells, we demonstrate that the entropy profiles are sensitive to particle sizes as varied through the synthesis method, including calcination (Fig. 1). The origin of those variations is further elucidated by in-situ XRD studies and thermodynamic calculations. We discuss, in how far those variations reflect an impact of the particle sizes on the stability of ordered and disordered phases, or rather are related to defects in the crystal structure. The density of such defects may as much depend on the synthesis route as the particle sizes do.
Furthermore, we demonstrate that entropy profile measurements are suitable to track the impact of cycle and thermal ageing2 on full cells. We show how full cell entropy profiles of new and aged cells can be calculated based on the half cell profiles of the fresh electrode materials. As confirmed by in-situ XRD measurements of new and aged cathodes (here: NMC and NCA), the changes observed in the entropy profiles can be explained without considering changes in the crystal structure of anode or cathode.

1 P. J. Osswald, M. del Rosario, J. Garche, A. Jossen, H. E. Hoster, Electrochimica Acta, DOI: 10.1016/j.electacta.2015.01.191

2 K. Maher, R. Yazami, J. Power Sources 261 (2014) 389

Figure 1
Degradation Diagnostics for Commercial Lithium-Ion Batteries
Authors: Birkl Christoph Robert , McTurk Euan , Roberts Matthew , Bruce Peter G , Howey David Alastair 
Published: February 2020

We present a method to diagnose electrode-specific degradation in commercial lithium ion (Li-ion) cells. The method is used to estimate the loss of active electrode material and lithium inventory resulting from long-term cycling of commercial cells.
Li-ion cells degrade due to a complex interplay of physical and chemical processes [1, 2], which lead to performance deterioration and, ultimately, cell failure. The various degradation mechanisms progress at different rates and have distinct effects on cell performance and lifetime. Some mechanisms, for instance lithium plating and dendrite formation, can result in internal short circuits and, in the worst case, fires or explosions [3]. The ability to identify the prevalent degradation mechanisms at any point in time is therefore crucial in order to anticipate the remaining lifetime of a cell accurately and to warn against imminent cell failure.
Many degradation mechanisms have a noticeable effect on the cell’s open circuit voltage (OCV) [4, 5]. The proposed method is designed to harness the information contained in the OCV by fitting a phenomenological OCV model [6] to the OCV of cells measured at different stages of their cycle life. The OCV model consists of parametric electrode sub-models and a full cell model, which combines the electrode OCVs by adjusting the loading ratio (the ratio of anode versus cathode capacity) and the offset (the portion of un-utilized cathode capacity), see Figure 1. Fitting the loading ratio and offset at various stages in the cell’s life allows estimation of the loss of active electrode material as well as the loss of lithium inventory. By tracking the rates of loss of active material and cyclable lithium, projections about the cell’s end-of-life can be made. Moreover, registering the loss of a critical amount of active anode material might prevent lithium plating and associated risks of cell failure.
The OCV model has been fitted to experimental data recorded on a 4 Ah, LiCoO2 pouch cell, which was cycled at 2C and 45°C, with pseudo OCV curves (C/20 charge and discharge) recorded every 100 cycles. Initial results have shown high accuracies of OCV model fits, with RMS errors < 15 mV (see Figure 2). In order to validate identified degradation mechanisms, the diagnostic procedure is repeated on commercial LiNiMnCoO2cells, which are subjected to post mortem analyses including electrochemical analyses on 3-electrode cells, scanning electron microscopy and XRD.

[1]
J. Vetter et al. , J. Power Sources, vol. 147, pp. 269-281, 2005.

[2]
P. Arora and R. E. White, J. Electrochem. Soc., vol. 145, no. 10, pp. 3647-3667, 1998.

[3]
Q. Wang et al., J. Power Sources, vol. 208, pp210-224, 2012.

[4]
M. Dubarry et al., J. Electrochem. Soc., vol. 9, no. 10, pp. A454-A457, 2006.

[5]
M. Dubarry et al., J. Power Sources, vol. 219, pp.204-216, 2012.

[6]
C. R. Birkl et al., Abstract no. 63, 227th ECS Meeting, 2015.

Figure 1