bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electrochemical Performances of Si Nanocrystals Embedded SiOx Nanosphere As a High Capacity Anode Material for Lithium-Ion Battery
Authors: Park Eunjun , Park Min-Sik , Lee Jaewoo , Kim Young-Jun , Kim Hansu 
Published: February 2020

Si has gained much attention as anode materials for lithium-ion battery due to its high theoretical capacity (3,580 mAhg-1) and low standard oxidation potential (0.4 V vs. Li/Li+). Despite these features, Si anode materials still have limits to commercial uses by poor cycle performance associated with their mechanical pulverization of Si due to severe volume change during alloying/dealloying with Li. To overcome this problem, various approaches have been suggested. In particular, the composites, which are composed of active Si and inactive buffer material, showed promising approaches for reducing the mechanical strain during cycles. On the other hand, nanostructuring of active materials would be helpful for further improvement of cycle performance. After heat treatment of Si/SiOx precursor at 1200 °C under inert atmosphere, we obtained Si nanocrystals embedded SiOx nanospheres with a size of 200 nm, in which about 10 nm sized Si nanocrystals are embedded in amorphous SiOx matrix. In order to improve electrical conductivity of Si/SiOx nanocomposites, carbon layer was coated on the surface of Si/SiOxnanocomposites.
The Si/SiOx nanospheres and C-coated Si/SiOx nanospheres were characterized by a field emission scanning electron microscope (FESEM), a high-resolution transmission electron microscope (HRTEM), X-ray diffraction (XRD) patterns, solid state 29Si magnetic angle spinning nuclear magnetic resonance (MAS NMR) and X-ray photoelectron spectroscopy (XPS) analyses.
The C-coated Si/SiOx composites showed a reversible capacity of 950 mAh/g-1 at current density of 200 mAg-1 with stable cycle performance over 100 cycles and high rate capabilities. In this presentation, the electrochemical properties of the C-coated Si/SiOx nanocomposites will be discussed in more detail.
Li Storage Properties of (1-x-y)Li[Li1/3Mn2/3]O2-xLiFeO2-yLiNiO2 Solid Solution Cathode Materials
Authors: Li Jiangang , Wang Lei , Chen Jiuhua , He Xiangming 
Published: February 2020

In view of cost and safety, some Fe-Mn based cathode materials such as LiFeO2-Li2MnO3 solid solution [1], Li(Li0.15Ni0.21Fe0.21Mn0.45)O2
[2] and Li1.2(Mn0.32Ni0.32Fe0.16)O2
[3] etc., were investigated in recent years. Our research group also developed a new cobalt free LiFeO2-Li2MnO3 based solid solution with a composition of Li(Li0.23Mn0.47Fe0.2Ni0.1)O2 to obtain high capacity of 277.4 mAh/g and better cycling stability [4]. In order to further optimize the solid solution composition to obtain the best electrochemical performance, the effects of solid solution composition on Li storage properties should be investigated thoroughly.
In this paper, a series of materials with the composition of (1-x-y)Li[Li1/3Mn2/3]O2-xLiFeO2-yLiNiO2(x+y£0.5)were prepared by sol-gel method, and the effect of annealing condition on the structural and electrochemical properties of as-prepared materials were investigated. The results reveal that all of materials prepared at 600 oC ~800 oC show pure layered a-NaFeO2 phase. However, the electrochemical performance varies with the solid solution composition. As shown in Fig.1, as-prepared materials with x+y=0.3~0.4 exhibit better cycling performance, indicating that suitable amounts of composited LiFeO2 and LiNiO2 in the solid solution is benefit for reducing the transformation of layered Li[Li1/3Mn2/3]O2 to spinel phase, and suitable amounts of composited Li[Li1/3Mn2/3]O2 can also restrain cubic LiFeO2 formation. Obvious cooperative effects are observed. In addition, as-prepared samples with high capacity of >210 mAh/g also distribute in this composition range, as shown in shadow area of Fig.1. However, high capacity of above 240 mAh/g can only be obtained while the material with composition of x/y<0.6 and x/y>2 in the shadow range. Further detailed discussion will be presented in the meeting.
References
[1] M. Tabuchi, Y. Nabeshima, T. Takeuchi, K. Tatsumi, J. Imaizumi, Y. Nitta, J. Power Sources 195 (2010) 834.
[2] X. Zheng, L. Cao, W. Zhu, X. Qiu, Acta Chimica Sinica,65 (2007) 571.
[3] K. Karthikeyan, S. Amaresh, G.W. Lee, V. Aravindana, H. Kim, K.S. Kang, W.S. Kim, Y.S. Lee, Electrochim. Acta 68 (2012) 246.
[4] Jiangang Li, Li Wang, Lei Wang,et al., J. Power Sources 244 (2013) 652.
Fig.1 The investigated (1-x-y)Li[Li1/3Mn2/3]O2-xLiFeO2-yLiNiO2 solid solution cathode materials
Production of Silicon Particles for High-Capacity Anode Material Yielding Outstanding Production Capacity
Authors: Andersen Hanne Flåten , Filtvedt Werner , Mæhlen Jan Petter , Mongstad Trygve Tveiterås , Kirkengen Martin , Holt Arve 
Published: February 2020

Silicon is proven to have a great potential as an anode material in lithium-ion batteries due to its high theoretical electrochemical capacity. The standard, commercial graphite anode has a theoretical capacity of less than 400 mAh/g, whereas the silicon anode can potentially deliver a tenfold capacity as a result of multiple Li-ion incorporation in the structure. However, silicon anodes deteriorate quickly during cyclic charging and discharging, rendering them useless in only a few cycles. This has been attributed to stresses induced by the large volume change of the material during cycling. The methods explored in order to overcome these problems such as using lithography, advanced nanotechnology, incorporation of silicon in carbon nanotubes or similar methods are too slow and too expensive for commercial use.
This work presents results from using a silane-based decomposition reactor in order to produce silicon particles with a suitable nanostructure for use in lithium-ion battery anodes. The silane gas is decomposed in a controlled environment at a temperature of 500-600 °C. The current pilot reactor has demonstrated production of up to 350 g/hour in an easily up-scalable lab version. Particles of diameter ranging from 50 nm and up to 500 nm have been produced with relatively narrow size distribution. This method may produce both amorphous and crystalline particles and the surface of the particles can be terminated by hydrogen or other elements if desired.
The silicon particles were mixed with an organic binder in an aqueous slurry and coated on a Cu-foil, The electrochemical performance was tested with CR-2032 coin cells. In the course of the presented work studies of cyclic voltammetry, cycling stability (Figure 1), voltage profiles and electrochemical impedance were performed. Besides electrochemical methods, SEM (Figure 2), XRD, ICP-MS and particle size distribution measurements were implemented. The silicon particles achieved a high capacity, relatively good stability, as well as a high yield and production capacity. Further developments on the silicon particles, such as doping of Si and in-line surface coating, are feasible.
Studies of Si-Fe-C Electrode Materials Prepared By Combinatorial Sputter Deposition
Authors: Al-Maghrabi M A , Dahn Jeff , Dunlap Richard A 
Published: February 2020

Introduction

Based on our previous studies (e.g. [1]) and other work [2], it is our opinion that silicon-based amorphous alloys are promising for use as a negative electrode. This is due to the fact that the volume expansion of amorphous silicon (a-Si) upon Li insertion is homogeneous and causes less pulverization as compared to the crystalline material. In addition to the homogenous expansion, the two-phase regions are inhibited once a-Si is used.
Herein, a combinatorial study, on Si-Fe-C sputtered films covering a wide range of compositions is presented. The intention is to study the effect of both Fe and C within the electrode on the electrochemical performance. Carbon was added in the hope that some carbon would remain “free” and could transport intercalated Li effectively to the interior of the particles, whereas iron can form an inactive matrix that reduces the overall volume expansion.

Experimental

Four combinatorial libraries in the Si-Fe-C system were produced using a Corona Vacuum Coaters model V3-T multi-target sputtering system described in [3]. Different targets, two inches in diameter, were used: a Si target, an Fe target and a C target. The targets and a plasma scrubber were mounted on magnetrons. The desired deposition profile was be achieved by using different stationary masks placed over the targets. Figure 1 summarizes the produced compositions.
X-ray diffraction was used to study the structure of these libraries and Mossbauer spectroscopy was employed to probe the atomic environment. Cyclic voltammetry measurements were performed using a multichannel pseudopotentiostat to study the behavior of these materials as negative electrodes for Li-ion batteries

Results and Discussion

Structural Studies:

X-ray patterns obtained from all compositions produced in this study were amorphous or nanostructured and no Bragg peaks indicative of any crystalline phases.
In order to understand the microstructure, as XRD measurements provide little detailed structural information, room temperature Mössbauer spectroscopy was performed on two libraries denoted by solid triangles and circles. The formation of Si-Fe phases were evident.

Electrochemical Analysis:

Figure 1(b) shows the potential versus capacity of the library denoted by the solid circles in Figure 1(a). Data for 64 electrode material are shown. Our combinatorial measurement setup allows for a simultaneous and rapid measurement. The impact of adding iron and carbon on the resulting capacity is illustrated clearly in Figure 1(b).
Through a combined consideration of Mössbauer effect measurements and electrochemical data, the formation of nanoscale regions of inactive Si-Fe and SiC phases was evident.
Organic Electrode Materials, a New Opportunity for Low Cost and High Power Lithium Battery?
Authors: Gutel Thibaut , Bataillé Sonia , Solan Sébastien , Maurel Vincent , Picard Lionel , Chapuis-Rey Marlene 
Published: February 2020

Nowadays electrodes of lithium batteries are mainly constituted by inorganic compounds based on transition metals such as cobalt, nickel or manganese. Although their performances are satisfying, these materials present several important drawbacks. Indeed these compounds are expensive because they are prepared due to energy-consuming techniques from rare mineral precursors. Moreover, some metals are toxic and often hard to recycle. Eventually their reactivity leads to safety issues in abusive conditions.
Organic compounds such as nitroxide based polymers offer a cost-effective and environmental friendly alternative to conventional active materials for high power batteries.1,2Interestingly these polymers can be prepared from low cost precursors using classical organic and polymer chemistry techniques. Moreover these compounds are easy to recycle or reuse at their end of life. But until now, their use in electrodes is still challenging due to their solubility in common electrolytes and their very low electronic conductivity.
Our work is focused on the synthesis and the grafting of nitroxide radical on a polymer backbone to prepare poly(2,2,6,6-tetramethyl-1-piperidinyloxy-4-ylmethacrylate) [PTMA]. Various functional crosslinker have been introduced in order to decrease the solubility and improve the ionic conductivity of these organic materials. These polymers have been fully characterized by Gel Permeation Chromatography, UV spectroscopy and Electron Spin Resonance. Electrolytes compositions have also been optimized in order to prevent the active materials from leaching into the solvent of electrolytes during cycling. In addition, our development of specific formulation allows us to implement these types of materials in electrodes of lithium batteries and some impressive electrochemical performances, especially at high C-rate, have been obtained.
This work is part of the ROPAS project and has been sponsored by the 7thframework of the EC.
1) Nakahara, Chem. Phys. Lett., 2002, 359, 351-354
2) Nishide, Electrochimica Acta, 2004, 50, 827-831
Nanostructured Porous Silicon - Carbon Anodes for Lithium-Ion Batteries: Two Novel Approaches
Authors: Biserni Erika , Xie Ming , Brescia Rosaria , Scarpellini Alice , Hashempour Mazdak , Mohaved Pooria , Bestetti Massimiliano , Li Bassi Andrea , Bruno Paola 
Published: February 2020

Silicon-based electrodes for Li-ion batteries (LIB) have recently attracted much attention because of their high theoretical capacity (~4000 mAh/g) and low average voltage (0.2 V) versus Li. However, the large volume change (~300%) due to Li-Si alloy formation results in poor cycling performance due to mechanical cracking and pulverization. It is believed that nanostructuring can help alleviate the effects of volume change and lead to improved cycling behaviour.
In this work, two novel approaches for composite Si-C anodes for lithium ion microbatteries are presented, based on the deposition of nanostructured porous Si films by Pulsed Laser Deposition (PLD) at room temperature and its coupling to a C layer.
In detail, the one approach is based on covering the as-deposited PLD porous Si films by a disordered graphitic C layer deposited by CVD that promotes the formation of a stable solid electrolyte interphase (SEI) layer, which is a critical step for an effective use of Si in LIB. In addition, the annealing effect induced by the CVD process on the anode is thought to be beneficial for its stability.
In the second approach, nanostructured Si is deposited by PLD on a foil made of carbon nanotubes (CNTs) that acts also as a current collector, thus making the underlying standard copper collector unnecessary. This dramatically reduces the thickness of the overall electrode, thus addressing the requirements for application in innovative microbatteries.
Introducing voids at the nanoscale in the Si film by nanostructuring is meant to accommodate the large volume expansion associated with silicon lithiation with no losses in film continuity (in contrast, for example, with films made of Si nanoparticles), while C is well known to be the standard material for LIB anodes for its good cycle life and capability of forming stable SEI layer with commonly used electrolytes. Moreover, the as-deposited Si film exhibits an amorphous structure in high-resolution TEM (HRTEM) and this avoids its amorphization during the first cycles, turning into lower internal mechanical stresses. Structure and morphology of the C-coated porous silicon samples have been widely investigated by suitable microscopic and spectroscopic techniques and their electrochemical behaviour characterized for different current densities.
With CVD carbon coating, porous silicon promisingly performs in a very stable way, showing areal capacity of ~175µAh/cm2 at 54 µA/cm2, and no decay for at least 1000 cycles.
On the other hand, also porous nanostructured silicon deposited on CNTs performs promisingly, showing areal capacity of ~150µAh/cm2 at 1080µA/cm2 with no decay for at 1000 cycles.
In-Situ SEM Study on Lithium Oxygen Battery
Authors: Zheng Hao , Xiao Dongdong , Li Xing , Liu Yali , Gu Lin , Wei Xianlong , Hu Yongsheng , Chen Qing , Wu Yang , Wang Jiaping , Jiang Kaili , Li Hong 
Published: February 2020

Rechargeable nonaqueous lithium-oxygen batteries have attracted wide attention recently due to its high theoretical energy density. Numerous challenges hinder its practical applications, including low round-trip efficiency, poor rate capability, cycle life on the side of the oxygen electrode, safety issue at lithium side, suitable and stable electrolytes. Among them, the reaction kinetics (ORR and OER) and the transport kinetics (ion transport and electron transport) are essential problems. Great efforts have been paid on fundamental understanding on the morphology, structure and composition of the products under various discharging and charging conditions. Obviously, direct in-situ investigation on the products during ORR and OER processes are desirable. Recently, a facile micro-scale solid state lithium-oxygen battery has been constructed in the environmental scanning electron microscope (ESEM). Based on the design, direct visualization of discharge and charge process of the lithium-oxygen battery has been achieved. Different discharge product morphology has been observed including sphere, conformal films and toroids. And the particles with the size up to 1.5 mm are formed upon discharge, while upon charge, the decomposition initiates at their surface and continues along certain direction. This new findings indicates that the transport kinetics of the electron and lithium ion seem faster on the surface than in the bulk of Li2O2, and the growth and decomposition process of Li2O2is supposed to be anisotropic.
Acknowledgement: Financial support from CAS project "Strategic Priority Research Program" of the Chinese Academy of Sciences (XDA01020304) and National project 973 (2014CB932300,2012CB932900) are appreciated.
Role of the Lithium Salt in the Performance of Lithium–Oxygen Batteries: A Comparative Study
Authors: Elia Giuseppe Antonio , Park Jin-Bum , Sun Y-K. , Scrosati Bruno , Hassoun Jusef 
Published: February 2020

Due to its high energy density, largely exceeding that of conventional lithium-ion batteries,[1–2] the Li/O2 battery is presently considered as a very promising energy storage system. However, the practical development of this battery is still hindered by several issues, such as: 1) the limited cycle number, affecting its life; 2) the high charge–discharge polarization, resulting in low energy efficiency, and 3) the occurrence of side processes due to moisture and carbon dioxide contamination that preventing its use in open air.
The choice of solvent and of electrolyte salt is expected to play a key role in influencing the cell behavior. To further investigate this important aspect, in this work we have examined the response of a Li/O2 cell using a tetraethylene glycol dimethyl ether electrolyte solutions, with four different salts, that is, LiPF6, LiClO4, LiCF3SO3, LiN(SO2CF3)2. This comparative study demonstrates that LiCF3SO3 salt is the best choice for assuring low cell polarization [3].
[1] B. Scrosati, J. Hassoun, Y.-K. Sun, Energy Environ. Sci. 2011, 4, 3287 –3295.
[2] G. Girishkumar, B. McCloskey, A. C. Luntz, S. Swanson, W. Wilcke, J. Phys. Chem. Lett. 2010, 1, 2193– 2203.
[3] Giuseppe Antonio Elia, Jin-Bum Park, Yang-Kook Sun, Bruno Scrosati, Jusef Hassoun, ChemElectroChem, DOI: 10.1002/celc.201300160.
Alternative Anode Materials for a Highly Stable Lithium Sulfur Battery
Authors: Brückner Jan , Thieme Sören , Althues Holger , Kaskel Stefan 
Published: February 2020

The lithium-sulfur battery system is expected to achieve more than double the gravimetrical energy density as state-of-the-art lithium-ion systems. At the same time the material costs can be significantly decreased due to the abundance and low price of sulfur.
What has kept the lithium-sulfur battery from commercialization is its low cycle stability of the system. In our work we demonstrate that the main problem is the metallic lithium anode, which is currently used in most of the publications. The aprotic solvent molecules of the electrolyte are instable versus lithium. When a low amount of electrolyte is used, the cell runs dry and reversible cycling is limited to less than 200 cycles.
Using hard carbon anodes we are able to demonstrate that prolonged, reversible cycling can be achieved for more than 1000 cycles. This system enables balanced lithium-sulfur full-cells with a lithium excess of only 10% and a low amount of electrolyte. The sulfur utilization can be increased to 1470 mAh g-1
sulfur (720 mAh g−1
cathode) by tuning the porosity of the cathode.[1] Our current generation hard carbon anodes achieve a stable areal capacity of 3 mAh cm-2 enabling a combination with high capacity cathodes. Dry processed sulfur cathodes exhibiting an areal loading of 2.5 to 3 mgsulfur cm-2and sulfur mass loading in the cathode of 68 wt% (including carbon matrix, conductive additive and binder) were applied and resulting full cell results will be discussed.
In addition the stable hard carbon anodes can be used to investigate degradation mechanisms in the lithium sulfur battery system. We present results that point toward the fact that nanometer-sized carbon host materials on the cathode side may suffer from increased mechanical degradation. In contrast micrometer-sized porous particles exhibit outstanding cycling performance.
Finally new approaches to transfer these results to high capacity anodes, based on Si/C composites will be discussed.

FIGURE1

Fig. 1: Cycle stability for a metallic lithium and all-carbon anode versus the same carbon-sulfur cathode at 836 mA g-1
sulfurand a limited amount of electrolyte.
[1] J. Brückner et al., Adv. Funct. Mater., 2013. DOI: 10.1002/adfm.201302169.
Investigations on Mechanisms of Ionic Transport and Phase Transition in Insertion Electrode Materials for Lithium/Sodium-Ion Batteries
Authors: Huang Xuejie , Sun Yang , Lu Xia , Pan Huilin , Zhao Liang , Hu Yong-Sheng , Gu Lin , Li Hong , Chen Liquan , Xiao Ruijuan 
Published: February 2020

Insertion electrode materials are included in the majority of ambient-temperature Li/Na-ion batteries, which attract increasing attention in energy storage. Being a commercialized cathode material of Li ion battery, olivine LiFePO4 has undergone intensive research. Previously, the two-phase separation mechanism upon charging was well accepted, while recent experimental results indicates a more subtle atomic structure, lithium-staging, exists upon charging. We show that, through first-principles calculations, the observed lithium-staging configuration in partially delithiated LiFePO4is a kinetically controlled thermodynamically metastable state. Our results shed light on the interactions between electron and ion and hence may have general implications for investigating the ionic transport in other strongly correlated mixed conductor materials. [1]
Spinel Li4Ti5O12 is well-known as a “zero-strain” anode for lithium-ion batteries. We found that it can also accommodate sodium ions, displaying an average storage voltage of 0.91V vs. Na+/Na. Through combined density functional theory calculations and scanning transmission electron microscope imaging techniques, a three-phase separation reaction, which has never been seen in any insertion electrode materials for lithium- or sodium-ion batteries, is confirmed in the sodiation process of Li4Ti5O12. Furthermore, interfacial structure is clearly resolved at an atomic scale in electrochemically sodiated Li4Ti5O12for the first time via the advanced electron microscopy. [2]

Acknowledge:

This work was supported by funding from the “863” Project (2009AA033101), “973” Projects (2013CB934002,2009CB220104)

Reference:

[1] Yang Sun, Xia Lu, Ruijuan Xiao, Hong Li, and Xuejie Huang. Chem. Mater. 24 (2012) 4693.
[2] Yang Sun, Liang Zhao, Huilin Pan, Xia Lu, Lin Gu, Yong-Sheng Hu, Hong Li, Michel Armand, Yuichi Ikuhara, Liquan Chen and Xuejie Huang. Nat. Commun. 4 (2013) 1870