bluuebunny/crossref_metadata_2025_split huggingface dataset:
Deformation of Lithium-Ion Battery Anodes during SEI Formation: a Probe for the Structure of the SEI
Authors: Jones Elizabeth M. C. , White Scott R. , Sottos Nancy R. 
Published: February 2020

Lithium-ion batteries are ubiquitous in small, portable electronics, where the lifetime of the battery now exceeds the expected lifetime of the device (ca. 2 years). Capacity fade over time, however, remains a significant challenge hindering the use of lithium-ion batteries in more demanding applications with long life-time requirements, such as in electric vehicles. One of the primary contributors to capacity fade is lithium trapping within the solid-electrolyte interphase (SEI) on the anode, making understanding the SEI critical to the design of more reliable lithium-ion batteries. The size-scale (tens of nanometers) and reactivity of the SEI, though, make characterization of the SEI difficult.
In this presentation, we present a new method to probe the structure of the SEI that is formed on lithium-ion battery anodes. A custom battery cell employs an unconstrained (i.e. not on a current collector) graphite composite electrode and allows optical access to the electrode during electrochemical cycling. Electrolyte is reduced on the electrode surface potentiostatically, and the resulting deformation of the electrode is measured using digital image correlation (DIC), an optical, full-field strain measurement technique. The amount of deformation of the electrode induced during SEI formation is related to the structure of the SEI layer. The strain measurements are then compared to galvanostatic cycling results, and the effects of different electrolyte salts, solvents, and additives on the SEI structure and battery capacity retention are evaluated.

Figure 1
The Limited Effect of VC in Graphite / NMC Cells
Authors: Deshpande Rutooj , Ridgeway Paul , Fu Yanbao , Zhang Wei , Cai Jinshu , Battaglia Vince 
Published: February 2020

Degradation at the electrode surfaces is one of the major reasons behind capacity fade in a well-constructed battery. The presence of electrolyte additives is known to alter the electrode particle surface which may in turn lead to changes in rates of intercalation as well as side-reactions. In particular, VC has been studied extensively for different lithium-ion chemistries and been shown to improve columbic efficiency of some electrodes. In the present study, the effect of vinylene carbonate (VC) as an electrolyte additive in a graphite/NMC 333 (lithium-nickel-manganese-cobalt oxide) cell is investigated. The study shows that the addition of VC improves the rate performance especially at moderately high rates. A new three-electrode cell design with Li as a reference electrode was used in this study. The three-electrode cell was particularly useful in studying the effect of VC on the rate performance of each electrode. The rate of side reactions is found to decrease with the addition of VC. Despite these important performance improvements, no significant improvement in the capacity retention is observed. This suggests that the side reactions in Gr./NCM cells consist of two types, those that go to repair cracked SEI on the anode and results in a net consumption of Li from the cathode and those that reform SEI components that dissolve from the anode and are oxidized at the cathode. The VC appears to reduce the second type but have negligible effect on the first. This also indicates that columbic efficiency measurements are not a reliable indicator of cell life with regard to short term capacity fade.
N-Doped Graphene-CNT Cathode Composites for High-Performance Li-S Batteries
Authors: Noorbehesht Nikan , Hollenkamp Anthony F. , Church Tamara L. , Harris Andrew T. , Minett Andrew I. 
Published: February 2020

Reaching beyond the horizon of Li-ion batteries is a formidable challenge, as energy storage will be more important in the future than at any time in the past. This requires the exploration of new chemistry, especially electrochemistry, and new materials. Among the available choices, lithium-sulfur (Li-S) batteries are attractive because of their low cost, environmental friendliness, and superior energy density (theoretically 2500 Wh/kg). Despite their great promise, the commercialization of Li-S batteries is hindered by low cycle stability, fast capacity fading, and low efficiency; these problems are induced by the polysulfide shuttle reaction that occurs through dissolution into electrolyte, the loss of active sulfur material, and the electronically insulating nature of sulfur. To tackle these issues, we synthesized a novel nanostructured composite consisting of Graphene and Carbon Nanotubes (CNT), each pre-doped with Nitrogen (N), as a host material for sulfur impregnation. In this unique composite, not only do CNTs act as the spacer units between the graphene sheets, avoiding losses in performance through restacking and agglomerate formation, but they also contribute to the material activity, overall surface area/nanoporosity, and the composite conductivity over the effective doping method strategy. In the next step, a new method of sulfur impregnating into the composite structure was implemented to effectively confine the sulfur into graphitic clusters, voids, and defects in N-doped graphene–CNT composite. The carbon nanostructured framework serves not only as a conductive layer for encapsulating sulfur and polysulfides without direct contact with electrolyte, but also as a nano-electrochemical reaction chamber. Cyclic voltammetry (CV) of the sulfur-impregnated N-doped graphene-CNT in high-dielectric solvent behaved similar to low-dielectric solvent, indicating that the material was not solvent dependent. Strong interaction between N-doped composite and sulfur or polysulfides enabled us to demonstrate Li–S cells
with a high reversible capacity (1005-1592 mAh/g), outstanding cycling stability, and great Coulombic efficiency (~97.5%). The results indicate that the sulfur-impregnated N-doped graphene-CNT nanocomposite is a very promising cathode material for high-performance lithium–sulfur batteries.

Figure 1
Strong Lithium Polysulfide Chemisorption on Electroactive Sites of Nitrogen-Doped Carbon Enables High-Performance Lithium-Sulfur Battery Cathodes
Authors: Song Jiangxuan , Yu Zhaoxin , Huang Qingquan , Gao Yue , Wang Donghai 
Published: February 2020

Lithium-sulfur (Li-S) batteries have attracted great of interest due to their high theoretical capacity of 1672 mAh/g and low cost.1 Unlike batteries with intercalation chemistries, Li-S batteries experience dissolution and diffusion of reaction intermediated (lithium polysulfides, Li2Sx, 2<x≤8) in the electrolyte. This behavior can lead to loss of active material from the cathode and to a polysulfide shuttle phenomenon, resulting in capacity fading and poor coulombic efficiency.2
,
3

Here, we report a novel functional carbon composite (carbon-nanotube-interpenetrated mesoporous nitrogen-doped carbon spheres, MNCS/CNT) as a sulfur host which can strongly adsorb lithium polysulfides. The nitrogen functional groups of this composite enable effective trapping of lithium polysulfides on electroactive sites within the cathode, leading to much improved electrochemical performance (1200 mAh/g after 200 cycles). The enhancement in adsorption can be attributed to chemical bonding of lithium ion with nitrogen functional groups in the MNCS/CNT framework. In addition, the micron-sized spherical structure of the material yields a high areal capacity (~6 mAh/cm2) with a high sulfur loading of ~5 mg/cm2, ideal for practical applications of Li-S batteries.

Acknowledgements

This work was supported by the Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Vehicle Technologies of the U.S. Department of Energy (DOE) under Contract No. DE-EE0005475.

References

1. A. Manthiram, Y. Fu, S.-H. Chung, C. Zu and Y.-S. Su, Chem. Rev., 2014.
2. J. Song, T. Xu, M. L. Gordin, P. Zhu, D. Lv, Y.-B. Jiang, Y. Chen, Y. Duan and D. Wang, Adv. Funct. Mater., 2014, 24, 1243-1250.
3. J. Song, Z. Yu, T. Xu, S. Chen, H. Sohn, M. Regula and D. Wang, J. Mater. Chem. A, 2014, 2, 8623.

Figure 1
Composite Prussian Blue Analogues Utilized As Cathode Materials in a Sodium Ion Battery
Authors: Sawicki Monica , Shaw Leon 
Published: February 2020

Increased environmental pollution and the inherent reliance of foreign import for fossil fuels and lithium have made the need for research towards alternative electrical energy storage systems. In this context, research in sodium ion batteries (NIBs) has become more prevalent since the price in lithium has increased due to its demand and reserve location. Sodium is an abundant resource that is low cost and safe which makes it an attractive alternative to lithium. Its chemical properties are similar to that of Li which makes the transition into using Na chemistry for ion battery systems feasible.
In light of the requirements for grid scale energy storage: ultra-long cycle life (>20,000 cycles and calendar life of 15 to 20 years), high round trip efficiency (>90%), low cost, sufficient power capability, and safety, the need for a suitable cathode material with excellent capacity retention such as Na2MnFe(CN)6/K2MnFe(CN)6 composite will be investigated. Prussian blue (A[FeIIIFeII (CN)6], A=Na+ or K+) and its analogues have been investigated as alkali ion hosts for use as a cathode material. They have a cubic face-centered structure in which two different metal centers Fe3+ and Fe2+ are bridged by C≡N- groups which provides large ionic channels along the <100> direction enabling facile insertion and extraction of alkali ions. This material is also capable of more than one Na ion insertion per unit formula which holds great promise in increasing the energy density of the NIB. Electrochemical impedance spectroscopy will be used to determine the conductivity of the composite Na2MnFe(CN)6/K2MnFe(CN)6 material. The electrochemical performance of the cathode material will be analyzed using cyclic voltammetry, and galvanostatic charge/discharge investigation.
Conductive Additive for Si/Mesoporous C Anode in Li-Ion Batteries: Conductive Graphite Vs Carbon Black C65
Authors: Rezqita Arlavinda , Trifonova Atanaska 
Published: February 2020

Silicon exhibits the highest theoretical capacity of 4200 mAh g-1, which is 10 times more than the capacity of graphite. Therefore, Si is a promising candidate for anode in lithium-ion batteries. However, Si has low electrical conductivity (theoretical: 6.7 x 10-4 S cm-1). To reach the high performance anode, the proper conductive additives are still needed in order to improve the electrical conductivity of Si-based anode. Here we investigated the effects of conductive nano-graphite and Carbon Black (CB65) on electrochemical performance of silicon-mesoporous carbon composite anode (Si/MC). The material has been synthesized by pyrolysis of polymer aerogel with embedded Si nanoparticles. The electrode was made by 75% active material, 15% conductive additive, and 10% polyacrylic acid (PAA) binder. The electrochemical characterization using impedance spectroscopy, voltammetry, and galvanostatic charge/discharge tests were conducted for both samples. Impedance spectroscopy showed that Si/MC anode with conductive graphite exhibited lower charge-transfer resistance (Rct ≈ 150 Ω), compared to those with carbon black (Rct ≈ 380 Ω). The collected results showed that the graphite additive improved significantly the electrochemical performance of Si/MC anode. In addition, the thermal and long cycling tests will be demonstrated.
Electrochemical Performance of Gas-Atomized Si-Alloy Anode for Lithium-Ion Battery
Authors: Kimura Yuta , Matsuoka Masashi , Tago Yuichiro 
Published: February 2020

Introduction

Si is focused as high capacity active anode material of lithium-ion battery. However, the large volume changes that occur during charge-discharge cycles cause cracking and falling conductivity of electrode. In order to prevent from these problems, various materilas that have structure covering Si surface by some substances such as SiOx have been studied1,2.
We have improved conductivity of Si anode material by fabricating the unique microstructure that crystalized alloy-matrix phases around Si phases3.Here, the Si-alloy powder was prepared by gas atomization. One of the important features of gas atomization process is to be able to produce quenched powder in large volume.
In this study, we investigated influence of Si composition and paticle size of gas-atomized Si-alloys on electrochemical properties for anode material such as cycle stability, initial clulombic efficiency, swelling of electrode during charge-discharge cycles.

Experiment

Si-alloy powder (d50 = 18 µm) was prepared by gas atomization. Fine powder (d50 = 2~5 µm) was obtained by planetary ball mill. An electrode was prepared by coating slurry of 80 mass% Si-alloy powder, 5 mass% ketjen black and 15 mass% polyamic-acid on SUS foil. The electrode was tested in a 2032-type coin cell assembled using a lithium foil anode, a separator and electrolyte (1M LiPF6 in EC/DEC (1:1 volume ratio)). The charge-discharge performance was evaluated at 25 degrees C and the current density of 0.2 mA (1st cycle), 0.2C-rate (from 2nd cycle to 50th cycle) in the potential range of 0.002-1.0 V vs. Li/Li+.

Results and Discussions

Fig.1 shows SEM image of Si-Sn-Fe-Cu alloy powder. The microstructure of the powder is composed of three phases (Si, Si-Fe and Sn-Cu phases). It can be seen that the Si phase is surrounded by Si-Fe and Sn-Cu phases.
Fig.2 shows cycle life performance of Si-alloy powder anodes having different particle size. When patricle size is large (d50 = 18 µm), the discharge capacity dropped with increasing cycle number. On the other hand, cycle stability of the fine powder (d50 = 2 µm) was drastically improved.
Fig.3 shows the relationship between the initial columbic efficiency and the Si composition of the Si-alloy. The initial coulombic efficiency decreaced by the particle size reduction and improved by increasing of the Si contens in the Si-alloy.
It was clarified that the particle size and the Si contents in the Si-alloy powder affected the electrochemical performance.

References

1.T.Morita, N.Takami, J.Electrochem. Soc., 153(2), A425(2006)
2.M.Miyachi et al., J.Electrochem. Soc., 152(10), A2089(2005)
3.Y.Tago et al., The Electrochemical Society in Japan 80th Spring meeting proceedings,1H22(2013)

Figure 1
Enabling High-Energy Battery Performance of 4.8 V Li-Rich Layered Oxide Cathode with a High-Voltage Additive
Authors: Pham Hieu Quang , Hwang Eui-Hyeong , Kwon Young-Gil , Song Seung-Wan 
Published: February 2020

Li-rich layered oxide of xLi2MnO3.(1−x)Li(Mn,Ni,Co)O2 is an attractive cathode material for high-energy density Li-ion batteries because of a possible attainment of high capacity as much as or higher than 250 mAhg−1 on the operation above 4.6 V vs. Li/Li+.1 Its performance however has been limited by high-voltage operation (> 4.3 V), due to anodic instability of conventional electrolyte and interfacial instability of the cathode. Here we report high performance of half-cell and full-cell with Li1.2Mn0.525Ni0.175Co0.1O2 cathode and fluorinated linear carbonate (di-(2,2,2 trifluoroethyl)carbonate, DFDEC) as a novel high-voltage electrolyte additive, on the high-voltage operation to 4.8 V.2 The full cell consisting of Li1.2Mn0.525Ni0.175Co0.1O2 cathode and graphite anode in the electrolyte of 1M LiPF6/EC:EMC only experiences a rapid capacity fade when being operated at 2.5- 4.75V, resulting in just 32 % capacity retention after 60 cycles. Although the performance improves with the use of DFDEC, a notable performance improvement is achieved when using the blended additives of DFDEC and VC, which is a well-known SEI-forming agent for graphite anode,3 delivering high discharge capacities of 231 − 189 mAhg−1 with the capacity retention of 82 % at the 60th cycle. The full-cell demonstrates doubled energy density (~278 Whkg−1) compared to ~136 Whkg−1 of a commercialized cell of graphite//LiCoO2. Spectroscopic surface chemistry studies indicate that DFDEC plays a critical role in stabilizing the SEI and inhibiting the interfacial degradation of cathode. The details of interfacial reaction (SEI formation) mechanisms, SEI composition and stability, and their relation to high-voltage cycling performance at room and elevated temperatures would be presented in the meeting.

References

1) M. M. Thackeray, S.-H. Kang, C. S. Johnson, J. T. Vaughey, S. A. Hackney, Electrochem. Commun., 8, 1531 (2006).
2) H. Q. Pham, K.-M. Nam, E.-H. Hwang, Y.-G. Kwon, H. M. Jung, S.-W. Song, J
.
Electrochem
.
Soc
., 161, A2002 (2014).
3) L. El Ouatani, R. DedryveÌre, C. Siret, P. Biensan, S. Reynaud, P. Iratçabal, D. Gonbeau, J. Electrochem. Soc., 156, A103 (2009).

Acknowledgement
s

This research was financially supported by the Korean Ministry of Trade, Industry & Energy (A0022–00725) and by the Ministry of Education (2012026203).
Impact of Electrochemical Charging on Fracture Toughness and Elastoplastic Properties of LiCoO2
Authors: Swallow Jessica G. , Woodford William H , McGrogan Frank P , Ferralis Nicola , Chiang Yet-Ming , Van Vliet Krysytn J. 
Published: February 2020

Capacity fade and impedance growth of lithium ion battery (LIB) electrodes have been correlated with mechanical degradation of active particles through extended cycling. The design of fracture-resistant electrodes requires understanding of material mechanical properties such as elastic modulus E, hardness H, and fracture toughness K
Ic over the entire range of compositions through which the active materials are cycled. In this work, we measured E, H, and K
Ic of the prototypical layered material LiXCoO2 using instrumented nanoindentation, varying the composition, X, through varying durations of galvanostatic charging. We found that within a single charge cycle, E and H decreased by up to 60%, while K
Ic decreased by up to 70% compared to the fully-lithiated state. X-ray diffraction, Raman spectroscopy, and optical and electron microscopy demonstrated that the drop in mechanical properties was correlated with extensive grain boundary fracture and attributable to Li depletion at the sample surfaces. Such differences in mechanical properties of Li-storage materials can impact the critical length scales (either grain size or particle size) that mark the boundary between fracture-resistant and fracture-prone electrode designs. This work demonstrates that when fracture toughness is used in battery design, it cannot be assumed to be constant over the course of charge cycling. This evidence of electrochemical-history-dependent fracture toughness is particularly important to the design of Li-storage compounds that undergo significant chemical expansion or phase changes during electrochemical cycling.
Inhibition of Al/Cu Contact Corrosion in Lithium Ion Batteries
Authors: El Mofid Wassima , Ivanov Svetlozar , Bund Andreas , Rentenberger Stephan , Goers Dietrich 
Published: February 2020

Nowadays, the safety of lithium ion batteries (LIBs) has attracted considerable attention. Therefore, battery components have been studied rigorously in a way to reduce safety problems such as explosion and fire accidents [1]. A key component in LIBs is the current collector which ensures electronic conduction between the electrode materials and the external circuit. Metallic Al which is widely used as the current collector material for the positive electrode in LIBs [2,3] might be subjected to contact corrosion, when connected to Cu, during the charge and discharge cycles. Such phenomena can shorten the lifetime and compromise the safety of LIBs.
This paper will discuss the corrosion behavior of various coatings on Al in contact with metallic Cu. The coatings Ni, Cu and NHP (Nickel High Phosphorus with about 10%P) were studied as corrosion protection coatings for Al current collector.
The anodic behavior of the three coatings on aluminum substrates in an organic carbonate based electrolyte were investigated by Cyclic Voltammetry (CV), Electrochemical Impedance Spectroscopy (EIS) and Scanning Electron Microscopy (SEM). CV data showed that already after the second cycle Cu and NHP exhibited very low current densities and good passivation behavior. Results analysis in Tafel coordinates also demonstrated better corrosion behavior for Cu and NHP samples expressed by a shift of the corrosion potentials to more anodic values. At the same time their corrosion rate values are lower.
EIS data showed no considerable variation with the polarization potential especially in the high frequency range. Moreover, in the Nyquist representation the EIS data take approximately the shape of a straight line, suggesting that the charge transfer resistance Rct is large and no corrosion takes place in the potential region [3.6V-4.2V].

References

[1] B. Scrosati, J. Garche, J. Power Sources 195 (2010) 2419.
[2] C. Iwakura, Y. Fukumoto, H. Inoue, S. Ohashi, S. Kobayashi, H. Tada, M. Abe, J. Power Sources 68 (1997) 301.
[3] A.H. Whitehead, M. Schreiber, J. Electrochem. Soc. 152 (11) (2005) A2105.
Silicon-Graphite Development: Robust, Practical, and Scalable High Performance Electrodes
Authors: Trask Stephen E , Polzin Bryant J , Kubal Joseph , Lu Wenquan , Jansen Andrew N. 
Published: February 2020

Lithium-ion batteries in their current state of technology are not able to satisfy the transportation requirements set by the U.S. Department of Energy (DOE) for Hybrid Electric Vehicles, Plug-in Hybrid Electric Vehicles, and Electric Vehicles for gravimetric and volumetric energy capabilities. One approach to meet DOE’s transportation goals is to increase the capacity of the anode using silicon. Silicon has been recognized for several years as the most likely next generation high energy anode material. However, the silicon drop-in replacement of graphite is not as straight forward as it would seem.
Argonne National Laboratory has taken on the task of developing a silicon-graphite blend electrode to advance the lithium-ion battery technology and provide high quality electrodes to the battery community for further electrolyte development. Fabricating a robust, practical, and scalable high performance silicon-graphite electrode, with an emphasis on developing an electrode with >3 mAh/cm2, has required efforts to explore various sources of silicon powder, silicon particle sizes, graphite types, binder types, electrode compositions, compatible solvents for slurries, effective slurry mixing, and electrode coating conditions. The approach involved testing silicon-graphite exploratory slurries on the CAMP (Cell Analysis, Modeling, and Prototyping) Facility pilot-scale coating equipment to address processing issues on the coater and verify the scalability of developments.
The result of this work led to a silicon-graphite electrode containing 15 wt.% nano-silicon, 73 wt.% graphite, 2 wt.% carbon black, and 10 wt.% Li-PAA (lithiated poly acrylic acid) binder. The slurry has the capability of coating at least a 3.7 mAh/cm2electrode and shows much improved robustness, practicality, scalability, and reproducibility (Fig.1). Having this standard electrode enables diagnostic work, modeling, and electrolyte composition work. The silicon-graphite electrode is available in the CAMP Facility Electrode Library for the battery research community. The major barriers encountered and breakthroughs in the silicon-graphite electrode fabrication leading to the improved electrode will be discussed in this presentation.
Acknowledgement:
Support from Peter Faguy and David Howell of the U.S. Department of Energy’s Office of Vehicle Technologies Program is gratefully acknowledged. This work was performed under the auspices of the US Department of Energy, Office of Vehicle Technologies, under Contract no. DE-AC02-06CH11357.

Figure 1