bluuebunny/crossref_metadata_2025_split huggingface dataset:
Omc for Poorly Conductive Products in Rechargeable Sodium-Air Batteries
Authors: Shin Hyeon-Ji , Kwak Won-Jin , Chen Zonghai , Yoon Chong seung , Lee Joong-Kee , Amine Khalil , Sun Yang-Kook 
Published: February 2020

Development of renewable energy resources requires high-efficiency energy conversion and large-scale, low-cost, high-density energy storage devices. The energy density of traditional Li ion batteries is inadequate to meet the increased requirements, especially for electric or hybrid electric vehicles. Metal air batteries1-5 have attracted a great deal of attention mainly because of the extremely high energy density of the metal-air battery system, which is close to the energy density of fossil fuels. One advantage of Na–air batteries over Li-ion or Li–air batteries is its low material cost and its natural abundance, as sodium is 30 times cheaper than lithium. Moreover, the energy density of a Na–air battery is similar to the maximum practical energy density of a Li–air battery (1600 Wh/kg).6 As a common challenge to be addressed for all air-based battery technologies, excessive discharge products can accumulate on the cathode surface; most of these have very low electrical conductivity, and thus tend to inactivate surface reaction sites and block oxygen diffusion channels. Hence, the over-accumulation of discharge products can lead to the increase in polarization during charging of the Na–air battery and eventual termination of the oxygen evolution reaction.7 To reduce the accumulation of discharge products for decreased charge potential and improved cycling performance, morphological properties of the cathode (e.g. surface area, pore volume, and pore size) need to be tailored while employing different catalysts. However, to the best of our knowledge, there have been no reports of research efforts to confine the size or arrangement of discharge products in the vicinity of the cathode to decrease the charge potential and improve the cycling behavior of Na–air batteries. In the present work, OMC having 2.7 nm size pore (OMC-2.7) was employed as a cathode material to control the formation and subsequent decomposition of discharge products, and thus to reduce polarization and improve cycling behavior.

References

[1] Abraham K. M., Jiang Z., J. Electrochem. Soc. 1996, 143, 1−5.
[2] A. Inoishi, S. Ida, S. Uratani, T. Okano, T. Ishihara, Phys. Chem. Chem. Phys. 2012, 14, 12818–12822.
[3] G. Cohn, Y. Ein-Eli, J. Power Sources 2010, 195, 4963–4970.
[4] J.-S. Lee, S.-T. Kim, R. Cao, N.-S. Choi, M. Liu, K. T. Lee, J. Cho, Adv. Energy Mater. 2011, 1, 34–50.
[5] S. Yang, H. Knickle, J. Power Sources 2002, 112, 162–173.
[6] Peled E., Golodnitsky D., Mazor H., Goor M., Avshalomov S., J. Power Sources 2011, 196, 6835-6840.
[7] Pascal Hartmann, Conrad L. Bender, Joachim Sann, Anna Katharina Du¨rr, Martin Jansen, Ju¨rgen Janek, Philipp Adelhelm, Phys. Chem. Chem. Phys. 2013, 15, 11661-11672.
Fast Assembly of Si-CNFs Anodes for High-Performance Lithium-Ion Batteries
Authors: Yao Meng , Liu Xingbo , Zhang Hui 
Published: February 2020

A hybrid lithium-ion anode material, made of acid-functionalized carbon nanofibers (CNFs) and amino modified Si nanoparticles (SiNPs), was synthesized by fast homogeneous electrophoretic deposition (EPD). Regular distribution of SiNPs in the three dimensional electro-active frameworks with the help of the interactions of surface functional groups can effectively improve the electron transport and restrict volume expansion during Li insertion/extraction. The as-deposited composite film exhibits a stable capacity of 790 mAh g-1 for 100 cycles at a current density of 400 mA g-1. The stability of suspension and weight ratio of Si to CNFs plays the key roles in the electrochemical performance. It provides a possible environmentally friendly and cost-effective preparation method for future high-performance Li-ion battery applications.
Geometric Characteristics of Three-Phase Porous Microstructures for All Solid-State Lithium Ion Batteries
Authors: Lim Cheolwoong , Penumaka Rani V , Murakami Sho , Song Zhibin , De Andrade Vincent , De Carlo Francesco , Kim Youngsik , Zhu Likun 
Published: February 2020

Fast lithium ion conducting inorganic solid materials are considered superior candidates for lithium ion batteries (LIBs) to overcome flammable characteristics, leakage, and tight electrochemical window issues of organic liquid electrolytes. Besides high ion conductivities of the inorganic materials, their wide electrochemical window and good chemical stability with electrode materials are great advantages as an electrolyte [1]. However, there are remained challenges to utilize the inorganic solid-state electrolytes for LIBs because of a low specific capacity, rate capability, and cycle life. Our previous study [2] showed a large capacity decay after the first charge and poor cycle life of an all solid-state LIB (Li1+xMn2O2 + Li1.3Ti1.7Al0.3(PO4)3 | Li1.3Ti1.7Al0.3(PO4)3 | Li1-xMn2O2 + Li1.3Ti1.7Al0.3(PO4)3). We concluded that the large capacity decay was caused by dismantled ion and electron pathway due to the structural change after the first charge. The electrochemical impedance spectroscopy results showed that the internal resistance of the solid-state cell has reduced by applying higher pressing pressure. Therefore, it is necessary to investigate the realistic microstructure to understand the capacity decay and poor cycle life of the all solid-state LIB.
By using synchrotron nano-computed tomography (nano-CT) at Argonne National Lab, we implemented quantitative study of the microstructures of all solid-state LIBs. The three-phase electrode was fabricated from a 47:47:6 (wt%) mixture of Li(Ni1/3 Mn1/3 Co1/3)O2 as active material (NMC), Li1.3Ti1.7Al0.3(PO4)3as Li-ion conductor (LTAP), and Super P carbon as electron conductor. The electrodes were packed under two different pressures (700 psi and 1300 psi) to control the volume fractions of void phase. To obtain the morphology data of the electrodes, TXM measurements were carried out adjusting energy levels of a synchrotron x-ray source. The x-ray generated images of solid-state electrodes with a 60 nm of spatial resolution at 8 keV are shown in Fig. 1. The gray-scaled intensity values of the images indicate the x-ray absorption rate of the materials. From the Fig. 1 (a) and (b), NMC particles, LTAP particles, and pores can be distinguished due to their different intensity values. Based on the reconstructed microstructure, the geometric characteristics will be presented to understand the lithium ion and electron pathways in all solid-state LIBs.
Acknowledgments: This work was supported by US National Science Foundation under Grant No. 1335850.
References
1. P. Knauth, Solid State Ionics, 180, 911 (2009).
2. N. M. Asl, J. Keith, C. Lim, L. Zhu, and Y. Kim, Electrochimica Acta, 79, 8 (2012).
Figure 1. Nano-CT images of solid-state electrode (NMC+LTAP) by full-field TXM measurements at an 8 keV of x-ray under packing pressures (a) 700 psi and (b) 1300 psi

Figure 1
Oxygen Reduction and Evolution Examined Using Quartz Crystal Microbalance and Electrochemical Methods in Non-Aqueous Li-O2 Batteries
Authors: Lindberg Jonas , Wickman Björn , Lindbergh Göran , Behm Mårten 
Published: February 2020

The Lithium-Oxygen battery is one of the most promising battery technologies being researched, it is also one of the more challenging ones due to the various problems associated with the battery. One of these problems is the poor understanding of the reaction occurring during oxygen reduction and evolution. It is known that the intermediates of the reaction are highly reactive and take part in unwanted side reactions. It is also known that the oxygen reduction products are poorly soluble in the electrolyte.
This study sets out to further examine these effects. Qualitatively these aspects are somewhat known but quantitatively the answer is less straight forward. By combining a Quartz Crystal Microbalance with electrochemical techniques the mass, current and voltage can be measured simultaneously to help shed further light on the species solubility and occurrence of side reactions. Obtaining this information about the chemical nature of the species formed will serve as a well needed compliment to the more frequently used surface characterization methods used when trying to determine the reactions occurring at the oxygen electrode.
New Metal Phosphide with Topotatic Reaction As an Anode Material for Lithium Ion Rechargeable Battery
Authors: Lee Sang-Min , Sim Sungju , Kim Jeom-Soo , Park Gumjae 
Published: February 2020

The current level of performances of Lithium Ion Batteries (LIBs) is not enough to meet commercial demands for new applications(xEV, ESS), in particular, with respective to energy density. Graphite and hard carbons are commonly used as a negative electrode material for LIBs, but higher-capacity alternatives are being consistently sought due to their limited capacity as an anode material of next generation LIBs for large-scale power applications. Recently, various Si, and Sn based compound including transition metal oxide, multiphase alloy, and intermetallic compounds have been extensively studied as alternatives to the existing carbon based anode material. These materials show much higher capacities than those of carbonaceous material. However, they are suffering from huge lattice volume change (4.4Li+Si ® Li4.4Si, ΔV>300%) through conversion reaction mechanism during Li insertion, which results in poor cycle life of LIBs.
In this respect, metal phosphides have been alternatively suggested as a promising anode material for their reversibility, and large amount of lithium uptake at relatively low potential. It is not clarified yet until now, but the electrochemical reaction in metal phosphides with lithium might be classified into two reaction mechanisms, depending on electronegativity difference between metal and phosphorous atoms. Obviously, the large difference in electronegativity between constituting elements inevitably brings about decomposition of host composition (structure) with lithium intercalation, which can be readily understood by considering the Gibbs formation free energy. Even if being composed of elements with the very small difference in electronegativity, however, the reaction mechanisms are different with chemical stoichiometry of metal phosphides (MPx). In case of SnPx (Electronegativity : Sn=1.96, P=2.19) intermetallic compounds, the SnP0.75 equilibrium phase shows typical conversion reaction mechanism, on the other hand, SnP0.94metastable phase has been observed to be on intercalation reaction mechanism during lithiation process [1,2].
In this work, we have investigated the reaction mechanism of MoPx(Electronegativity : Mo=2.16, P=2.19) with various stoichiometry, relating with electrochemical properties. We finally propose newly designed metal phosphide with ternary composition showing topotatic reation.

References

[1] Young-Ugk Kim, Churl Kyung Lee, Hun-Joon Sohn, and Tak Kang, Journal of The Electrochemical Society, 151 (2004) A933-A937
[2] Youngsik Kim, Haesuk Hwang, Chong S. Yoon, Min G. Kim, and Jaephil Cho, Adv. Mater.19 (2007) 92–96
Electrochemical Performance of Dual Doped Li4Ti5O10 for Use at Anodes of Lithium Ion Batteries
Authors: Cetin Deniz , Hua Keping , Gopalan Srikanth 
Published: February 2020

Formation of solid electrolyte interphase (SEI) increases the cell internal impedance and reduces the charge rates in lithium ion batteries (LIB) and causes significant cell performance limitations. Lithium titanate, Li4Ti5O10 , (LTO) is a promising lithium storage material for anodes that does not form SEI, but it suffers from poor charge and discharge rates which arise from low lithium ion and electron conductivity at operation temperatures.
In order to improve the performance of the LIB anode, ionic and electronic conductivities should be enhanced. We present a novel approach in this work to simultaneously increase the ionic and electronic conductivities by dual doping of LTO. Doped materials are synthesized at temperatures higher than 800°C and analyzed using electrochemical impedance spectroscopy.
SnOx/Carbon Core Shell Structure: An Efficient Anode for Rechargeable Sodium Ion Batteries
Authors: Kalubarme Ramchandra S. , Park Ga-Eun , Park Chan-Jin 
Published: February 2020

Lithium-ion batteries have been widely used as energy storage media in portable electronic devices, electrical vehicles, hybrid electrical vehicles, etc. In particular, they have become indispensable energy storage devices for intermittent energy conversion applications such as solar cells and wind power. However, the low abundance and uneven distribution of lithium resources show the potential difficulties of the long-term and large-scale applications of lithium-ion batteries in aspects of their availability and cost. Accordingly, the development of new types of batteries, such as sodium-ion and magnesium-ion batteries, is necessary. Among them, sodium (Na)-ion batteries (NIBs) possess electrochemical working principles that are similar to LIBs. In addition, sodium is inexpensive and abundant. Therefore, NIBs could substitute LIBs in applications such as smart grids and large-scale energy storage for renewable solar power and wind power.
The major obstacle in realizing NIBs has been the absence of suitable anodes. Most of all, graphite which has been a commercially well-known anode material for LIBs cannot be used as an insertion host for Na ions due to their large ionic size. Moreover, only few noticeable studies on negative electrode materials, e.g., lead and hard carbon have been reported thus far. Metal oxides are considered to be important electrode materials, as they follow a conversion reaction mechanism. However, metal oxides suffer from several problems when used as anode materials which limit their use, such as swelling and shrinking of active material particles upon the insertion and extraction of Li+ or Na+ ions, which can induce poor contact between the active materials and the electron conducting agents, leading to low electric and ionic conductivity.
In this study, we report the electrochemical activity of carbon coated SnOx nanostructures for NIBs. The nanostructured SnOx were synthesized by a hydrothermal method and their surfaces were coated by carbon to improve the electric conductivity. The effect of solvent used for hydrothermal process and annealing temperature on the structure, morphology and Na storage capacity was investigated. The single phase SnO2 was obtained using ethanol solvent, while the blend of SnO and SnO2 was obtained using DI water and ethylene glycol solvents. The transmission electron microscopic images conform the presence of carbon coating on the SnOx nanoparticles. Further, the anodes made of carbon coated SnOx prepared in ethanol solvent exhibited stable cycling performance and attained the capacity of about 443 mAh/g in the first charge. With the help of the conductive carbon, the carbon coated SnO2 delivered more capacity at high rates; 257 mAh/g at the 1 C-rate, 156 mAh/g at the 5 C-rate and 70 mAh/g at the 10 C-rate. The excellent cyclability and high-rate capability are attributed to the formation of a mixed conducting network and the uniform carbon coating formed on the SnO2 nanoparticles.
3D Nanoarchitecture of Ge/C Core-Shell for Ultra-High Rate Anode for Lithium Ion Batteries
Authors: Ngo Duc Tung , Lee Jae-Young , Park Chan-Jin 
Published: February 2020

The mobile world depends on lithium ion batteries (LIBs), which provide portable power for variety of applications, ranging from personal electronic devices such as laptops, mobile phones and digital cameras to electric vehicles due to their high energy density, low self-discharge and long cycle life.
Currently, the anode material in commercially available LIBs is made of graphite, which has the specific capacity of 372 mAh/g, but it cannot meet the world’s growing demand for batteries with higher energy density, power density and rate capability. For further increasing the energy and power density of LIBs, the replacing graphite carbon anode by new advanced materials with higher reversible capacity and rate capability as well as long-term cyclability is considered an attractive route. In this context, the lithium alloys based material emerged as a promising alternative candidate to replace graphite as an anode material for LIBs due to their high specific capacity.
Here, we propose a facile method to prepare 3D nanoarchitecture of carbon coated Ge (3D-Ge/C) using simple method. The 3D-Ge/C constructed from secondary particles of Ge/C composite with diameter of about 100 nm that composed of nanometer-size (~10 nm) primary particles of Ge coated with carbon. Through carbon coating on the nanosized Ge, the aggregation of Ge particles in nano scale is completely prevented. As a result, outstanding capacity and rate capability can be achieved with this structure, 3D-Ge/C exhibited a high reversible capacity of 1604 mAh/g at the rate of C/10 after 100 cycles and excellent rate capability. In particular, at high rate of 100C (160 A/g) the average capacity of 1122 mAh/g was observed and at ultrahigh rate of 400C (640 A/g) the average capacity of 429 mAh/g was recorded.
New Flame-Retardant Composite Separators Based on Metal Hydroxides for Lithium-Ion Batteries
Authors: Daeyong Yeon , Lee Yunju , Cho Insung , Song Seonghyun , Ryou Myung-Hyun , Lee Yong Min 
Published: February 2020

In order to enhance the thermal stability of conventional polyolefin separators, we propose a novel composite separator based on metal hydroxides. In particular, metal hydroxides not only function as a thermally stable mechanical matrix like alumina (Al2O3) or silica (SiO2) but also flame retardant due to their ability to release absorbed water molecules under some accidental conditions (e.g. higher than 200 oC).
The flame-retardant composite separators are prepared by coating both sides of a microporous polyethylene (PE) membrane with nano-sized metal hydroxide (Al(OH)3 and Mg(OH)2) ceramic powders and poly(vinylidene fluoride-co-hexafluoropropylene) PVdF-HFP binder. Their physical properties are evaluated via scanning electronic microscopy (SEM) for surface morphology, the densometer to measure Gurley number (permeability), electrochemical impedance spectroscopy for ionic conductivity, and uptake amount of liquid electrolyte for wettability. In addition, the flame retardancy of composite separator is investigated by measuring the extinction time. Furthermore, the electrochemical properties of composite separators are evaluated with lithium-ion cells composed of a graphite anode and a LiCoO2 cathode. Comparing to bare separators, the composite separators show improved flame retardancy and rate performances due to water release property and better electrolyte wettability, respectively.

Acknowledgement

This research was financially supported by the Ministry of Education, Science and Technology (MEST) and National Research foundation (NRF) of Korea through the Human Resource Training Project for Regional Innovation (2014066977) and This research was ﬁnancially supported by Chungcheong Leading Industry Promotion Project of the Korean Ministry of Trade(R0001485).
MoO2/Mo2C hybrid Nanowires As Anode Materials for High Performance Lithium Ion Batteries
Authors: Yang Lichun , Sun Wei , Zhong Zhiwei , Wang Yukun , Gao Qingsheng , Zhu Min 
Published: February 2020

Molybdenum oxides, mainly including MoO3 and MoO2, are attractive materials with potential applications in catalysis, sensors and energy storage. Owing to the good electronic conductivity, high stability and density, MoO2 was proposed as a host material for lithium ions. However, the application of MoO2 as anode material for lithium ion batteries was limited in the early research, due to the low capacity and poor cycling stability resulting from the bulky dimensions, the consequential slow kinetics and huge volume changes during the charge/discharge process. To improve the performance of MoO2, a most promising way is to design and construct nanostructured composites[1-3].
Here we report on a facile synthesis of MoO2/Mo2C hybrid nanowires through simple calcination using MoOx/amine nanowires as a precursor. The small diameters of the nanowires ensure fast lithium ion insertion and extraction, while the long dimensions benefit good electron transport between wires. Besides, The electrochemical inactive Mo2C with a high specific conductance distinctly increases the structural stability and electronic conductivity of the hybrid nanowires. As a result, the cycling and rate performance of the hybrid nanowires is remarkably enhanced. At a current density of 1000 mA/g, a discharge capacity of ~ 700 mAh/g is still retained after 300 cycles, which indicates the MoO2/Mo2C hybrid nanowires a promising anode material for high performance lithium ion batteries.
Acknowledgements
This work was financially supported by the National Natural Science Foundation of China (Nos. 51402110, and 51231003), and the Fundamental Research Funds for the Central Universities (2013ZM0002).
References
[1] Q.S. Gao, L. C. Yang, X. C. Lu, J. J. Mao, Y. H. Zhang, Y. P. Wu, Y. Tang, J. Mater. Chem., 2010, 20, 2807.
[2] L.C. Yang, L. L. Liu, Y. S. Zhu, X. J. Wang, Y. P. Wu, J. Mater. Chem., 2012, 22, 13148.
[3] H. J. Zhang, K. X. Wang, X. Y. Wu, Y. M. Jiang, Y. B. Zhai, C. Wang, X. Wei, J. S. Chen, Adv. Funct. Mater., 2014, 24, 3399.
Bottom-up Synthesis of Copper Fluoride Nanocomposites and Their Application to Rechargeable Li Batteries
Authors: Chun Jinyoung , Kim Youngsik , Lee Jinwoo 
Published: February 2020

Copper fluoride (CuF2) is one of the attractive cathode candidates for rechargeable Li batteries that have high theoretical operation potential (3.55 V vs. Li/Li+) and large specific capacity (528 mAh/g). However, synthesizing nanostructured CuF2, as well as harnessing its potential rechargeability, has been a challenge because of it inherent chemical and electrochemical properties. Only top-down approaches have been reported for down-sizing CuF2, and there are no reports on reversible electrochemical performance of CuF2 even at the first several cycles. Herein, we report a facile and versatile synthetic method for CuF2/mesoporous carbon nanocomposites and their application to the cathodes of rechargeable Li batteries. Through heat treatment with NH4F in a solventless system, CuF2 was easily synthesized from various copper precursors. CuF2 nanoparticles confined in mesoporous carbon exhibited not only superior specific capacity and rate capability at the first discharge in the normal coin-type cell, but also promising cycle performance in the solid-electrolyte-incorporated cell. To the best of our knowledge, this is the first report in which nanostructured CuF2 is synthesized using a bottom-up approach and successfully applied to rechargeable Li batteries.