bluuebunny/crossref_metadata_2025_split huggingface dataset:
Determination of Individual Contributions to the Ionic Conduction in Litf/Pegdme-150 Liquid Electrolyte
Authors: Popovic Jelena , Maier Joachim 
Published: February 2020

Current salt containing liquid lithium electrolytes show both cationic and anionic conductivity with lithium transference numbers below 50% leading to formation of the ion concentration gradients inside a lithium battery cell. Moreover, the possibility of indirect (vehicular) transport of lithium ions from one electrode to the other via ion pair diffusion is usually neglected when typical DC polarization measurements are performed.[1] If the concept of Conservative Ensembles [2] is employed, effective conductivity can be deconvoluted into transport contributions from free ions and ion pairs even when higher order aggregates are present.[3] We demonstrate experimentally that a combination of DC polarization, impedance spectroscopy and PFG-NMR can enable such analysis for an electrolyte composed of poly(ethylene glycol) dimethyl ether (PEGDME-150) and lithium trifluoromethanesulfonate (LiTf) salt at ambient temperature.[4] In this case, the influence of ion pairs is substantial at all concentrations with values exceeding pure lithium conductivity (in 1M LiTf/PEGDME-150, only 5% of the current is transported by solvated Li+ while 21% is transported via Li-Tf ion pair under applied voltage). By including IR spectroscopy in the arsenal of techniques, mobilities of all species as well as effective mass action constants are calculated for the first time.

J. Maier,
Advanced Functional Materials, 21, 1448, 2011.

J. Maier, Journal of the American Ceramic Society, 76, 1212, 1993.

J. Maier, Electrochimica Acta, 129, 21, 2014.

J. Popovic, C. Pfaffenhuber, J. Melchior, J. Maier, Electrochemistry Communications, 60, 195–198, 2015.
Improved Lithium-Sulfur Cell with a Thin Barrier Membrane
Authors: Moy Derek , Narayanan S. R. 
Published: February 2020

The development of a high cycle life rechargeable lithium-sulfur battery is of substantial interest due to its high theoretical specific capacity of 1675 mAh/g and energy density of 2600 Wh/kg. These properties combined with the low cost and abundance of sulfur are attractive for practical and high performance lithium-sulfur batteries. However, the realization of these lithium-sulfur batteries have been limited by performance issues relating to their poor cycle life and low energy efficiency. The typical lithium-sulfur cell loses 20-50% of its initial capacity within 100 cycles due to a parasitic reaction known as the polysulfide shuttle.
The polysulfide shuttle originates from the inherent solubility of the higher order polysulfides, S8
2-, S6
2-, and S4
2-, at the positive electrode. These polysulfides are capable of shuttling between the positive sulfur electrode and negative lithium electrode. When a polysulfide species contacts the negative electrode, it will be reduced to a lower order polysulfide species. If reduced to another soluble species such as S6
2- or S4
2-, it will shuttle back to the positive electrode where it must be reoxidized, resulting in charging inefficiency. If reduced to an insoluble species such as S2
2- or S2-, it will precipitate, resulting in irreversible capacity loss. Therefore, inhibiting the polysulfide shuttle is necessary to improving the energy efficiency and cycle life of lithium-sulfur batteries.
We herein present a method of inhibiting the polysulfide shuttle through use of a thin barrier membrane. The thin barrier membrane is non-porous and capable of conducting lithium ions. The non-porosity of the membrane allows for physical exclusion of polysulfide species from the lithium electrode while the ionic conductivity allows for transport of lithium ions necessary for charge and discharge processes. In a cell configuration, the thin barrier membrane is sandwiched between two porous separators to maintain electronic isolation and inserted between the sulfur and lithium electrode.
We have studied the effect of the thin barrier membrane in 2032-type coin cells consisting of sulfur-carbon composite positive electrodes, lithium foil negative electrodes, and 1 M LiTFSI electrolyte. The performance of the membrane was compared to cells of similar construction without the membrane and also to cells with 0.25 M lithium nitrate, the state-of-the-art polysulfide shuttle inhibiting additive. We have analyzed the performance of all cells using galvanostatic cycling, electrochemical impedance spectroscopy, and direct shuttle current measurements.1 We have found that the thin barrier membrane improves the energy efficiency and cycle life of lithium-sulfur cells by suppressing the polysulfide shuttle.
References:
1. D. Moy, A. Manivannan, and S. R. Narayanan, J. Electrochem. Soc., 2015, 162, A1-A7

Figure 1
Aqueous Ceramic Coating upon Hydrophobic Polyethylene Lithium-Ion Battery Separators through Use of an Anionic Surfactant
Authors: Jeon Hyunkyu , Yeon Daeyong , Lee Taejoo , Park Joonam , Hwang Suyeon , Ryou Myung-Hyun , Lee Yong Min 
Published: February 2020

Highly thermal stable and robust ceramic-coated separators (CCSs) should be included for large-format lithium-ion batteries (LIBs) to secure their safety even at various abnormal conditions such as automobile accident. However, the ceramic coating layer of a few micrometers needs additional coating and slitting processes, resulting in increasing the separator price. Moreover, the hydrophobicity of polyethylene separators requires non-polar organic solvent-based coating slurry consisting of ceramic particles and polymeric binders. In general, organic solvents started to be excluded in the industry field owing to their environmental pollution and additional recovery facility. That is why aqueous ceramic coating process should be developed while overcoming its wetting problem upon hydrophobic polyethylene separators.
Herein, we newly introduce an anionic surfactant, containing both hydrophobic and hydrophilic groups, to make the aqueous slurry be well-dispersed and easily wetted upon polyethylene separators. Due to the cationic property of Al2O3 surface in water, anionic surfactants are appropriate in this application. Among various them, we have chosen disodium laureth sulfosuccinate (DLSS) for this system. We optimized the water-based ceramic coating process using DLSS and investigated the physical properties of Al2O3 ceramic-coated separators. We also studied the electrochemical properties of cells containing the CCSs.
Acknowledges
This research was supported by the New Technology Convergency Type Growth Engine Project of the National Research Foundation (NRF) funded by the Ministry of Science, ICT & Future Planning (NRF-2014M3C1A8074768) and the Human Resource Training Program for Regional Innovation and Creativity through the Ministry of Education and National Research Foundation of Korea (NRF-2014H1C1A1066977)
Synthesis and Identification of Al-Based Ultrathin Films on Well-Defined Oxide Nanocrystals for Li-Ion Batteries
Authors: Hu Linhua , Cabana Jordi 
Published: February 2020

Chemical degradation and capacity fading is one of challenge in LIBs due to the loss of active cathode material from interaction at the interface of the cathode and electrolyte.1 The use of coatings based on a non-active oxide, e.g. Al2O3, is a prevailing strategy to decrease such degradation based on their role as electronic insulator between cathode and electrolyte.2,3 Although many strategies have been reported using different synthetic methods, the surface coating is not well controlled owing to random deposition of precursor on powders of complex morphology, which results in inhomogeneities that leave active surfaces without proper passivation. Therefore, the synthesis of uniform thin films based on aluminum oxides with controlled thickness, coated on each nanocrystal of an active oxide is an important prerequisite to improve the durability of cathode materials.
Herein, LiCoO2 (LCO) nanoplates were directly synthesized by a hydrothermal process and subsequent coating of aluminum oxide by precursor decomposition and thermal treatment. Figure 1(a) and (b) show TEM images of as-prepared bare LCO nanoplates and coated LCO nanoplates. The edge length and thickness of hexagonal nanoplates is about 50nm and 10~20nm. The exposed surfaces are (001) and (010). 1~2nm thick alumina were uniformly coated on LCO nanoplates. EDX mapping and line scan has confirmed the LCO core and alumina shell structure. The thermal treatments were performed at 400~600oC for 3hours. The size of LCO didn’t change after coating. The electrochemical properties have demonstrated the enhanced effect of alumina coating. The balance of capacity and cycling ability is dependent on different temperature and loading of alumina.
References:

Jonathon L. Tebbe, Aaron M. Holder, and Charles B. Musgrave. ACS Appl. Mater. Interfaces, 24265-24278, 7(2015). Mechanisms of LiCoO2 Cathode Degradation by Reaction with HF and Protection by Thin Oxide Coatings

Seung-Taek Myung, Kentarou Izumi, Shinichi Komaba, Hitoshi Yashiro, Hyun Joo Bang, Yang-Kook Sun, and Naoaki Kumagai J. Phys. Chem. C 2007, 111, 4061-4067, 111(2007). Functionality of Oxide Coating for Li[Li0.05Ni0.4Co0.15Mn 0.4]O2 as Positive Electrode Materials for Lithium-Ion Secondary Batteries

Jun Liu and Arumugam Manthiram. Chem. Mater.
1695-1707, 21 (2009). Understanding the Improvement in the Electrochemical Properties of Surface Modified 5 V LiMn1.42Ni 0.42Co0.16O4 Spinel Cathodes in Lithium-ion Cells

Figure 1
Stabilization of Cubic-Na3PS4 to Enhance Ionic Conductivity of Solid Electrolytes for All-Solid-State Sodium Sulfur Batteries
Authors: Kompella Christopher , Nguyen Han , Hy Sunny , Zhu Zhuoying , Chu Iek-Heng , Ong Shyue Ping , Meng Ying Shirley 
Published: February 2020

Solid-state electrolytes (SSE’s) are crucial in realizing the potential of novel rechargeable batteries. All-solid-state batteries with inorganic solid electrolytes offer a number of advantages by improving safety, reliability, and cost [1]. Sulfide glasses are promising as a solid electrolyte due to their superionic ionic conductivity [3]. Na3PS4 is a glass-ceramic that is precipitated from the sulfide glass matrix, exhibiting ionic conductivities of 10-6 and 10-4 S/cm for the tetragonal and cubic phases, respectively [4]. Here we provide a simple synthesis process for stabilizing the cubic phase, which also reduces the activation energy to 330 meV. We also investigate anion doping, which can further improve upon this result by increasing Na vacancies, via a composition curve of Cl-doping to determine optimal concentration of (1-x)Na3PS4-xNaCl, for 0 > x > 0.0625.
Acknowledgements
This work was supported by National Science Foundation under grant number ACI-1053575.
References
[1] Kamaya, Noriaki et al. “A Lithium Superionic Conductor.” Nature Materials10.9 (2011): 682–686. Web.
[2] Hayashi, Akitoshi et al. “Superionic Glass-Ceramic Electrolytes for Room-Temperature Rechargeable Sodium Batteries.” Nature Communications 3.May (2012): 856. Web.Tatsumisago, Masahiro, and Akitoshi Hayashi. “Sulfide Glass-Ceramic Electrolytes for All-Solid-State Lithium and Sodium Batteries.” International Journal of Applied Glass Science10 (2014): 226–235. Web.
[3] Ribes, M., B. Barrau, and J.L Souquet. “Sulfide Glasses: Glass Forming Region, Structure and Ionic Conduction of Glasses in Na2S-XS2 (X=Si, Ge), Na2S-P2S5, and Li2SGeS2 Systems.” Journal of Non-Crystalline Solids39 (1980): 271–276. Print.
[4] Hayashi, Akitoshi et al. “Superionic Glass-Ceramic Electrolytes for Room-Temperature Rechargeable Sodium Batteries.” Nature Communications 3.May (2012): 856. Web.

Figure 1
Interconnected Ge/Cu Nanostructured Anodes for High Areal Capacity Li-Ion Microbatteries
Authors: Lee Gwang-Hee , Lee Seun , Mho Sun-Il , Kim Dong-Wan 
Published: February 2020

Li-ion microbatteries (LIMBs) have been rapidly developed in integrated smart micro-systems for bio medical devices and wearable devices. To improve rapidly integrated micro-systems, it is important to develop LIMBs with high energy and power density per unit area. Therefore, areal (or volumetric) capacity is more important than gravimetric capacity. Specially, anode materials having high areal capacity can provide a more effective way to develop advanced high-performance LIMBs. Ge anode materials could also realize high volumetric capacities of approximately 8650 mA h cm-3, similar to volumetric capacities of Si anode materials. In addition, three-dimensional (3-D) conducting networks with Ge anode materials could provide synergistic effects. The 3-D conducting networks offers the opportunity to lead high areal capacity because of increasing mass loading of active materials per unit area, improving electronic and ionic pathways by interconnected open channel networks, and relaxing of the volume expansion during discharge/charge cycling.
Herein, we suggest to design newly 3-D network structures which could load massive Ge anode materials for high energy and power density per unit area. We fabricated highly ordered 3-D Ge nanoarrays loaded on Cu nanowire-network current collectors (Ge/Cu Nanowire-Networks). As the Cu nanowire-network current collector, the Cu nanonets were synthesized by MOCVD (metal-organic chemical vapor deposition) using a Cu(C2H3O2)2∙H2O powder. And then, the Ge nanowires as anode materials were deposited onto the as-prepared Cu nanonets using the thermal evaporation of Ge powder. Loading mass of the Ge nanowires is dependent on deposition time. To provide porous structures, the prepared samples removed spontaneous oxide layers by 0.2 vol% H2SO4 solution.
We performed electrochemical performance tests of the Ge/Cu Nanowire-Networks with various mass loadings (from 0.7 to 7.0 mg cm-2). The Ge/Cu Nanowire-Networks showed stable high areal capacity (> 2 mA h cm-2) at a current density of 1 mA cm-2 over 140 cycles and the excellent rate capability of 1.3 mA h cm-2 at a current density of 5 mA cm-2. The Ge/Cu Nanowire-Networks with a mass loading density 7.0 g cm-2 has been fabricated, achieving a high areal capacity of 6.4 mA h cm-2 after 40 cycles. Also, we performed EIS analysis to determine the relationship between the electrochemical performance and electrode kinetics. To investigate morphologies and phases of the Ge/Cu Nanowire-Networks, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) were employed.
Influence of Excess Lithium on the Electrochemical Performance of Li1+Z
MnTiO4 Spinel Structure for High Capacity and Long Cycle Life
Authors: Vu Ngoc Hung , Im Won Bin 
Published: February 2020

Spinel based lithium manganese oxide is the most attractive cathodes for lithium-ion battery due to high capacity, low cost, and non-toxic. This material has a theoretical high capacity of 296 mAh g-1 (2 Li+ ions) if Li+ ions are fully inserted/extracted into/from the spinel structure. However, it is well known that when LiMn2O4 is discharged to a low voltage, e.g., 2 V, high spin Mn3+ ions may induce severe Jahn-Teller distortion. Up to date, this material is only used in the 4 V region with a low capacity of 120 mAh g-1. [1, 2]
Much effort has been made to enhance the cycle stability of such cathode materials in a wide voltage window (e.g., 2.0-4.8 V). The substitution of titanium for manganese can improve the cycle life of cathode materials but with a decrease in the capacity of material which restrict its usage in a broad application. [2, 3]
In this paper, Li1+z
MnTiO4 (z = 0, 0.5, and 1) were developed to solve the problems of low capacity and short cycle life. Excess lithium material (z = 0.5 and 1) formed a solid-solution with notation (1-a)LiMn2-x
Ti
x
O4.aLi2Mn
y
Ti1-y
O3, which improve the capacity of material up to 218 mAh g-1, after 60 cycles with a capacity retention of 93 %. The structure and electrochemical properties were investigated carefully through X-ray diffraction, galvanostatic cycling, cyclic voltammetry (CV), galvanostatic intermittent titration technique (GITT) to understand the mechanism of the improvement in the capacity and cycle stability of material. We also analyzed the effect of impurity phase as a significant factor that affects the electrochemical performance of the cathodes.

References

Thackeray, M.M. Prog. Solid State Chem. 1997, 25 (1–2), 1-71

Wang, S.; Yang, J.; Wu, X.; Li, Y.; Gong, Z.; Wen, W.; Lin, M.; Yang, J.; Yang, Y. J. Power Sources. 2014, 245, 570-578.

Chen, R.; Knapp, M.; Yavuz, M.; Heinzmann, R.; Wang, D.; Ren, S.; Trouillet, V.; Lebedkin, S.; Doyle, S.; Hahn, H.; Ehrenberg, H.; Indris, S. J. Phys. Chem. C. 2014, 118 (24), 12608-12616.

Figure 1
Facile Reduction of Pseudo-Carbonates: Promoting Solid Electrolyte Interphases with Dicyanoketene Alkylene Acetals in Lithium-Ion Batteries
Authors: Forestier Coralie , Jankowski Piotr , Coser Laura , Gachot Grégory , Sannier Lucas , Johansson Patrik , Grugeon Sylvie , Laruelle Stéphane , Armand Michel 
Published: February 2020

In recent years, greener transportation has become of major interest to limit air pollution and global warming. For this purpose, Li-ion batteries (LIBs) are considered as the most promising power source for electric vehicles (EV) and hybrid electric vehicles (HEV) due to their high energy density. The use of high-energy multi-cell battery packs imposes ever more stringent requirements on LIBs in term of safety and long-term cyclability.
The formation of an effective SEI passivation layer at the negative electrode / electrolyte interface was found to be of paramount importance in order to enable LIB long-life cycling and controlling the threshold for thermal runaway. This is why SEI-forming additives have been used in the electrolyte to reinforce these protective properties, with the most common additives being vinylene carbonate (VC) (1), fluoroethylene carbonate (FEC) (2), and vinyl ethylene carbonate (VEC) (3).
To our knowledge, the modification of EC and PC on the carbonyl group, rather than on the alkylene bridge as for VC, VEC, or FEC, has not previously been attempted.(4,5) It is known that the =C(CN)2 group is an “oxygen equivalent” being even slightly more electronegative than O itself and extending considerably the conjugation. Hence, we hypothesized that modified EC or PC, with C=C(CN)2 replacing the carbonyl groups, could lead to a more facile reduction at higher potentials and a stable SEI.
The dicyanoketene propylene (and ethylene) acetal, DCKPA (DCKEA), have both been synthesized according to a simple procedure.(6) The reduction process has been investigated for DCKPA by means of GC/MS and IR analysis and the efficiency as a SEI-reinforcing additive demonstrated by the analysis of the soluble products using liquid GC/MS.
The cycling tests using a pouch cell configuration at both 20 and 45°C were realized with only 0.5 wt.% of additive in the electrolyte and resulted in higher capacity retention. Moreover, a post-mortem analysis by DSC revealed an improvement in term of safety due to an improved lithiated graphite/electrolyte interface.
[1] H.-H. Lee, Y.-Y. Wang, C.-C. Wan, M.-H. Yang, H.-C. Wu, D.-T. Shieh, Journal of Applied Electrochemistry. 35 (2005) 615–623.
[2] I.A. Profatilova, S.-S. Kim, N.-S. Choi, Electrochimica Acta. 54 (2009) 4445–4450.
[3] Y. Hu, W. Kong, H. Li, X. Huang, L. Chen, Electrochemistry Communications. 6 (2004) 126–131.
[4] C. Forestier, P. Jankowski, L. Coser, G. Gachot, L. Sannier, P. Johansson, et al., Journal of Power Sources. 303 (2016) 1–9.
[5] Pending patent
[6] W.J. Middleton, V.A. Engelhardt, Journal of the American Chemical Society. 80 (1958) 2788–2795.

Figure 1: Results of cycling tests at 45°C without and with 0.5 wt.% of DCKPA using a pouch cell configuration, and the post mortem DSC / liquid GC/MS analyses.

Figure 1
Exploring Cycling Behavior of NMC532//Gr-Si Cell in Fluorinated Carbonates Electrolytes
Authors: Pupek Krzysztof Z. 
Published: February 2020

In the quest to increase energy density of lithium-ion cells, silicon-containing negative electrodes have been extensively investigated. The long-term performance of these electrodes is limited due to the instability of the electrode-electrolyte interface that is continually disrupted during the lithation-delithiation cycles. Therefore, the development of an electrolyte formulation that enhances the stability of the interface would be a significant step forward.
We conducted a comparative study of several fluorinated carbonates like methyl 3,3,3-trifluoroethyl carbonate, bis(3,3,3-trifluoroethyl) carbonate, 3,3,3-trifluoropropylene carbonate, and mixtures thereof as solvents for NCM523//Gr-Si CR2032 cell electrolyte formulations.
Comprehensive data from rate study, impedance and cycle life evaluation tests will be presented and discussed.
Layered-to-Rock-Salt Transformation in Desodiated NaCrO2
Authors: Bo Shou-Hang , Li Xin , Toumar Alexandra J. , Ceder Gerbrand 
Published: February 2020

O3 layered sodium transition metal oxides (i.e., NaMO2, M = Ti, V, Cr, Mn, Fe, Co or Ni) are a promising class of cathode materials for Na-ion battery applications. These materials, however, all suffer from severe capacity decay when a large amount of Na is extracted from the hosts. Understanding the causes of this capacity decay is the key to fully unlock the potential of these materials for battery applications.
In this work, we elaborate the capacity fading mechanism for one of the compounds in this class, i.e., NaCrO2. The (de)sodiation processes of NaCrO2 were first characterized by in situ XRD. Using a slow cycling rate (C/50), a phase diagram of NaxCrO2 close to thermodynamic equilibrium could be constructed. Ex situ synchrotron XRD and electron diffraction were then performed on samples that were charged to selected stages of charge. Through these and additional ab initio computation, we demonstrate that NaxCrO2 (0 < x < 1) remains in the layered structure framework without Cr migration up to a composition of Na0.4CrO2. Further removal of Na beyond this composition will trigger a layered to rock-salt transformation converting the P'3-Na0.4CrO2 to a rock-salt CrO­2 phase, which is responsible for the capacity fade of NaCrO2. This structural transformation proceeds via the formation of an intermediate O3-CrO2 phase that contains Cr in both Na and Cr slabs. It is intriguing to note that intercalation of alkaline ions (i.e., Na+ and Li+) into the rock-salt CrO2 is actually possible, albeit in a limited amount (~0.2 per formula).
Preventing the layered to rock-salt transformation is of uttermost importance to improve the cyclibility of NaCrO2. Possible strategies for circumventing this detrimental phase transition will be proposed. We believe insights obtained in this work can be potentially applied to other O3 type of Na and Li transition metal oxides, and can serve as strong basis for future materials design of NaCrO2 based cathodes.