bluuebunny/crossref_metadata_2025_split huggingface dataset:
Structural and Chemical Synergistic Encapsulation of Polysulfides Enables Ultralong-Life Lithium-Sulfur Batteries
Authors: Wang Xiaolei , Li Ge , Li Jingde , Chen Zhongwei 
Published: February 2020

The fast depletion of fossil fuels and deterioration of environment have led to increasing demand for renewable energies and efficient energy storage technologies. Lithium-sulfur (Li-S) batteries have been regarded as one of the most promising high-energy power sources in broad applications ranging from electric vehicles to large-scale grid energy storage. Li-S batteries deliver a theoretical energy of 2600 W h kg-1 that is an order of magnitude higher than that of the current lithium-ion batteries (LIBs), and utilize naturally abundant sulfur as the cathode material which significantly reduces the cost. The major challenge for the practical implementation of Li-S batteries resides in the dramatic capacity decay. The intermediate lithium polysulfides (Li
x
S
n
, 3≤n≤8) formed during cycling dissolve in the liquid electrolyte, migrate through the separator, and deposit on Li metal anode, causing “shuttle effect”. In addtion, the utilization of the active material is strongly hampered by the intrinsic insulating of S and its discharge product Li2S, leading to a low capacity and poor rate capability. Furthermore, the S cathode suffers from the volume variation (~80%) during lithiation/de-lithiation, causing the loss of electrical contact and the structure instability.
Herein, we demonstrate an innovative strategy to efficiently entrap Li
x
S
n
from synergistic effect of structural restriction and chemical encapsulation using metal oxide-decorated hollow sulfur spheres. The significance of this strategy lies in that we purposely design a material architecture with both structural and chemical encapsulation effect, and that the material architecture provides a prolonged cycling stability. MnO2 is selected as a model and the MnO2 nanosheets-decorated hollow S spheres (hollow S-MnO2) nanocomposites are achieved through a facile synthesis. The nanocomposites with unique structure possess several features favoring highly stable S electrodes: i) the hollow spheres with inner void space not only alleviate the volume expansion of S on lithiation but also structurally restrict soluble Li
x
S
n
within the spherical structure; ii) the decorated MnO2 nanosheets with large surface area efficiently and chemically minimize the polysulfides dissolution by forming strong bonding; iii) the small dimensions of hollow S-MnO2 nanocomposites facilitate both ion and electron transport, leading to a better utilization of the S. This design presents a new strategy to prevent loss of polysulfides by structural and chemical dual-encapsulation, and can be expanded to other metal oxides or metal hydroxides. The unique material architecture enables high-performance S cathodes with high capacity, high sulfur loading and extremely low capacity decay of only 0.028% per cycle over 1500 cycles at 0.5 C-rate.

Figure 1
Extending Cycle Life of Lithium-Sulfur Cells Using a Flexible and Selective Lithium-Ion Conducting Membrane
Authors: Moy Derek , Narayanan S. R. 
Published: February 2020

Lithium-sulfur chemistry has the potential to overtake Lithium-ion battery technology with its high theoretical specific capacity at 1675 mAh/g and energy density at 2600 Wh/kg. These properties coupled with the low cost and natural abundance of sulfur makes the lithium-sulfur battery attractive as a cost-effective and high energy density battery solution. However, the large scale deployment of these lithium-sulfur batteries have been severely limited by their poor cycle life. The typical lithium-sulfur cell loses over 20% of its initial capacity within its first 100 cycles. One of the major causes of these capacity losses is a parasitic reaction known as the polysulfide shuttle.
The polysulfide shuttle is present in all lithium-sulfur cells due to the inherent solubility of the higher order polysulfide discharge products, S8
2-, S6
2-, and S4
2-. These soluble polysulfides constantly shuttle between the sulfur and lithium electrodes. When these species contact the negative lithium electrode, they are reduced to shorter chain polysulfides that must shuttle back towards to sulfur electrode to be re-oxidized. However, some polysulfides such as S4
2- are reduced to insoluble S2
2-on the surface of lithium electrode, resulting in an irreversible capacity loss. Inhibiting the polysulfide shuttle is necessary to protect the lithium electrode as well as to prevent capacity loss.
We demonstrate the ability to inhibit the polysulfide shuttle using a lithium-ion selective membrane. The membrane is a thin, flexible, and non-porous barrier layer that restricts all soluble polysulfide species at the sulfur electrode and prevents their diffusion towards the lithium electrode. The membrane is ionically conducting to allow transport of lithium ions necessary for charge and discharge processes. The membrane remains inert to polysulfide species at all operating voltages and presents a barrier to growth of lithium dendrites and catastrophic failure. In a cell configuration, the membrane is electronically isolated from the two electrodes by using porous separator layers placed on either side of the membrane.
We tested the lithium-ion selective membrane in 2032-type coin cells using sulfur-carbon composite positive electrodes, lithium foil negative electrodes, and 1 M LiTFSI electrolyte. The performance of cells containing the lithium-ion selective membrane was compared to cells without the membrane as well as to cells with 0.25 M lithium nitrate (the state-of-the-art polysulfide shuttle suppressing additive). We analyzed the performance of these cells using galvanostatic cycling, electrochemical impedance spectroscopy, and direct shuttle current measurements1. We found that the lithium-ion selective membrane improves the cycle life of lithium-sulfur cells through inhibition of the polysulfide shuttle.
References
1. D. Moy, A. Manivannan, and S. R. Narayanan, J. Electrochem. Soc., 2015, 162, A1-A7

Figure 1
Modeling the Thermodynamic and Kinetic Effects on the Electrochemical Performance of Planar Na-NiCl2 Batteries
Authors: Kim Chang-Soo , Xu Yihan , Li Guosheng , Park Yoon-Cheol , Jung Keeyoung 
Published: February 2020

Na/metal chloride batteries (i.e., Na-NiCl2 or Na-FeCl2 batteries) possess a number of excellent properties including high safety and stability, high energy density, high voltage, no self-discharge, and good cycle life. Relying on these advantageous features, these Na/metal chloride secondary cells have a high potential for applications of transportation and vehicles as well as the advanced stationary energy storage systems (ESS). In these Na/metal chloride batteries, the electrochemical performance is largely determined by the thermodynamics and kinetic reactions in the cathode area comprised of NaCl particles, Ni/NiCl2 and/or Fe/FeCl2 powders, NaAlCl4 secondary electrolyte (i.e., catholyte), and various additives. During the charge-discharge process, complicated electrochemical reactions will occur in this cathode of the cell, including ionic diffusion of Na+ through NaAlCl4 catholyte driven by the chemical potential and the electric potential gradients, dissolution/coarsening of NaCl particles, and precipitation/decomposition of NiCl2 or FeCl2.
The presentation introduces a continuum computational model to capture the quantitative effects of reaction thermodynamics and transport kinetics on the electrochemical performance of Na/metal chloride batteries with a Na-NiCl2 cell chemistry. The computational model was developed using a commercial COMSOL multi-physics software package. The model was applied to characterize a novel planar cell, which was designed adopting a disc shaped beta-alumina solid electrolyte (BASE) instead of a conventional cloverleaf shaped BASE. The planar cell geometry was intended to lower the cell operation temperature by optimizing the cell performance. In this multi-physics computational model, relevant physicochemical materials properties of active materials have been incorporated. The cell voltage was calculated using the Butler-Volmer kinetic equation and the temporal volume change of the active materials was computed based on the local current densities. The computation results were used to quantitatively investigate the effects of (1) cell operation temperature, (2) cathode active materials to catholyte ratio, and (3) cell dimension on the charge-discharge characteristics of the planar Na-NiCl2 cell. Especially, the combined effect of operation temperature and cell size on the cell performance was of special interest. It turns out that the electrochemical performance of the Na-NiCl2 cells is highly dependent on the cell operation temperature to show reduced cell voltages with decreased operation temperatures.
Synthesis and Electrochemical Activity of Sodium Titanium Phosphate for Sodium Ion Battery
Authors: Kim Doyoub , Park Heetaek , Kang Byoungwoo 
Published: February 2020

Lithium ion batteries have become the very foundation of today’s wireless technology especially mobile electronic devices. However, there has been a growing concern on its scarcity and rising price1. At the same time, large scale applications, electric vehicle and energy storage system, brought upon the needs for low cost and environmentally clean battery system. In this context, sodium ion batteries meet the needs since it is naturally abundant and economic feasible.
Identical to the research on negative electrode materials for lithium ion batteries, much of that for sodium ion batteries have been focused on carbonaceous materials, oxides and polyanionic compounds2. Among these categories, negative electrode materials consisting of polyanionic compounds especially phosphates become of great interest because of their thermal and structural stability3.
In this talk, we report sodium titanium phosphates that can be usable for anode materials of sodium ion batteries with either aqueous electrolyte or non-aqueous electrolyte. Depending on the synthesis conditions of this material, it has two different polymorphs. While one is electrochemically active, the other isn’t. Furthermore, we will present the effect of two polymorphs’ structure on the materials’ electrochemical activity.
Reference

J. M Tarascon, M. Armand, Nature 2001, 414, 359

N. Yabuuchi, K. Kubota, M. Dahbi, S. Komaba, Chemical Reviews, 2014, 114, 11636-11682

G. Hautier, A. Jain, S. P. Ong, B. W. Kang, C. Moore, R. Doe and G. Ceder, Chem. Mater. 23, 3495-3508, 2011.
Theoretical Overpotentials for Metal Anodes
Authors: Nagy Kyle Steven , Kazemiabnavi Saeed , Siegel Donald J 
Published: February 2020

Metals, especially those with low standard electrode potentials, are attractive candidates for use as anodes in rechargeable batteries because of their generally higher capacities compared to intercalated graphite. In order to be practical, these metals should efficiently plate and strip with low overpotentials during battery cycling. In general, overpotentials have thermodynamic and kinetic contributions. An important thermodynamic contribution arises from heterogeneity in the [de/ad]-sorption energy due to inequivalent reaction sites on the electrode surface. Here we systematically calculate thermodynamic overpotentials for plating and stripping on seven metal electrodes (Li, Na, K, Mg, Ca, Zn, and Al) of relevance for “beyond Li-ion batteries.” For all metals the potential limiting steps are terrace reactions, corresponding to deposition of atoms onto an otherwise empty terrace during plating, or creation of a vacancy in a terrace (pit formation) during stripping. These reactions may be considered as nucleation events, with the added/removed adatom as the critical nuclei. Coordination number of the metals correlates with overpotential: alkali metals with BCC coordination exhibit amongst the most efficient plating and stripping thermodynamics. In agreement with experiments, the cycling of Ca anodes are predicted to be highly inefficient.
The Effects of Electrolyte Variations on the Oxygen Efficiency in Lithium Air Batteries
Authors: Ryu Kyoung Han , Kim Won Keun , Seo Samuel , Lee Ho-Teak 
Published: February 2020

While the existing lithium-ion batteries have been extensively used in electric vehicles (EVs), their limited specific energy restricts the driving range. In this context, rechargeable lithium air (or Li-O2) batteries have attracted considerable interest in recent years as a potential power source for EVs, owing to their high theoretical specific energy. A typical non-aqueous lithium air battery consists of a porous air electrode, a lithium metal anode, and electrolyte containing lithium salt. The electrolyte is generally regarded as a critical component as it is directly related to the stability and the performance of a lithium air battery. While physicochemical properties of potential electrolytes are often discussed, the ability of electrolyte to utilize the oxygen during reversible charge/discharge cycle is rarely explored. In fact, previously reported gas analysis indicated low current efficiency for O2 evolution during charging (Li2O2 → 2Li+ + O2 + e-), accompanied the evolution of byproduct gases such as H2 and CO2.1-2 Furthermore, the O2 revolution (therefore, rechargeability) seemed highly dependable on the choice of electrolyte.
In this work, we investigated the oxygen efficiency during discharge/charge cycle in lithium-air using differential electrochemical mass spectrometry (DEMS). We explored various electrolytes that have the potential to prompt reversible electrochemistry in Li-O2 battery. In addition to this, the effect of a catalyst and lithium salt variation on the O2 evolution was investigated.
1) B. D. McCloskey, D. S. Bethune, R. M. Shelby, G. Girishkumar, and A. C. Luntz, J. Phys. Chem. Lett., 2, 1161 (2011)
2) C. J. Barile and A. A. Gewirth, J. Electrochem. Soc., 160, A549 (2013)
Exploration of Side Reactions Based on Graphite-Li2O2 Redox Couple for Lithium Oxygen Battery
Authors: Zhang Wang , Shen Yue , Huang Yunhui 
Published: February 2020

In recent years, lithium oxygen batteries (LOBs) have been considered as one of most promising energy storage systems for long-range electric vehicles and smart grid due to its high energy density.1-3 However, there are many fundamental scientific problems hinder it’s realization from theory to practice, including the sluggish oxygen evolution reaction (OER), the instability of electrode/electrolyte and the contamination of H2O/CO2/N2 in air. The instability of electrode and electrolyte always leads to serious side reactions which result in high charge overpotential and poor cycle life. In the study of LOBs, Li metal is usually used as the anode material to achieve high energy densities because Li is the lightest and most electropositive metal. Besides, the amount of Li metal is always far enough in our battery system. Thus, the electrochemical performance obtained with excess amount of Li metal could not reflect the true performance of our battery due to the existing side reactions which will constantly consume the lithium sources.4

To solve this problem, we used a graphite-Li2O2 redox couple for LOBs. Fig. 1 shows the typical charge-discharge profiles of Li-graphite, Li-O2 and graphite-Li2O2 batteries. Further, we systematically investigated the side reactions occurred in this battery system and evaluated its impact on the cycle performance of LOBs. Graphite has been widely used as anode material in commercial lithium ion battery, and has also been investigated in lithium sulfur and lithium oxygen batteries.4-6 In our cases, we used LISICON protected graphite as anode to avoid the contamination of O2. Lithium peroxide-carbon composites were used as cathode and acted as the only lithium source for LOB. The battery was cycled at different C-rates and the cathode was measured by multiple analysis methods including SEM, TEM, Raman/FTIR, HNMR etc.
Reference
1. Abraham, K. M.; Jiang, Z. J. Electrochem. Soc.
1996, 143, (1), 1-5.
2. Bruce, P. G.; Freunberger, S. A.; Hardwick, L. J.; Tarascon, J.-M. Nat. Mater.
2012, 11, (1), 19-29.
3. Luntz, A. C.; McCloskey, B. D. Chem. Rev.
2014, 114, (23), 11721-50.
4. Chun, J.; Kim, H.; Jo, C.; Lim, E.; Lee, J.; Kim, Y. ChemPlusChem
2015, 80, (2), 349-353.
5. Agostini, M.; Scrosati, B.; Hassoun, J. Adv. Energy Mater.
2015, 5, (16), 1500481.
6. Bhargav, A.; Fu, Y. J. Electrochem. Soc.
2015, 162, (7), A1327-A1333.

Figure 1
Tuning Dopant Chemistry in the Na3PS4 Glass-Ceramic Electrolyte
Authors: Chu Iek-Heng , Zhu Zhuoying , Kompella Christopher , Nguyen Han , Deng Zhi , Hy Sunny , Meng Ying Shirley , Ong Shyue Ping 
Published: February 2020

Cubic Na3PS4 (c-Na3PS4) [1] is one of the most promising sodium superionic conductor solid electrolytes that may enable safer and more energy dense rechargeable batteries based on sodium-ion chemistry. Experimentally, Na+ conductivities as high as 0.74 mS cm-1 have been achieved via improvements in synthesis and doping.[2] In this talk, we will present an integrated first principles and experimental study of the effect of dopant chemistry on Na+ conductivity in Na3PS4. Using ab initio molecular dynamics (AIMD) simulations,[3] we show that pristine c-Na3PS4 is in fact an extremely poor Na ionic conductor, and it is only with the introduction of Na+ excess via M4+ for P5+ doping that reasonable conductivities close to the experimentally observed values are achieved. A systematic evaluation of different M4+ dopants find that 6.25% Sn4+ doping may yield an even higher Na+ conductivity, albeit with a slight increase in doping energy. We will also present recent results on alternative doping strategies that yield similarly high conductivities in the tetragonal polymorph (t-Na3PS4), with the potential advantages of a simpler synthesis path and improved SEI composition at the electrode-t-Na3PS4 interface.
References:
[1] Hayashi, A.; Noi, K.; Sakuda, A.; Tatsumisago, M., Nat. Commun, (2012), 3, 856.
[2] Tanibata, N.; Noi, K.; Hayashi, A.; Tatsumisago, M., RSC Adv., (2014), 4, 17120.
[3] Zhu, Z.; Chu, I.-H.; Deng, Z.; Ong, S. P., Chem Mater., (2015), 27, 8318.
Resistive Sensors Based on Self-Assembled Core-Shell Nanoparticles
Authors: Baklouti Linda , Rajoua Khalil , Favier Frederic 
Published: February 2020

A gas sensor allows the detection thanks to the specific reactivity of its sensitive material towards the target gas.
The use of resistive sensors is based on measuring the variation of their electrical conductivity when the target gas is in contact with the sensitive material.
In our study, we chose to work with self assembled core-shell nanoparticles as sensing materials. The idea consists on decorating spherical gold nanoparticles, insensitive to the target gases, with a shell based on a different material. The latter provides the specific sensitivity to the sensor.
Previous works in our laboratory focused on Au@Pd and Au@Pt nanoparticles as H2 sensors. These works were extended to other shell materials to examine their sensitivity towards H2 as well as other target gases including NH3.
Au@ZnO, Au@SnO2 and Au@Ag nanoparticles were synthetized and then assembled by Langmuir Blodgett technique. The assembly resulted in close-packed core-shell nanoparticle monolayers. These layers were transferred, by simple dip-coating, to a glass slide supporting interdigitated electrodes. Sensing performances of the as fabricated sensors were evaluated through the resistivity changes in the discontinuous particle assemble.
The sensitivity of Au@ZnO and Au@SnO2 based sensors was tested towards H2 while Au@Ag based sensors were tested under NH3. All sensors showed responses towards the target gases. The effect of humidity and the sensing temperature on the sensing performances were studied. Besides, among the main sensor proprieties requested and studied we note : sensitivity, selectivity, response and recovery times.
Assembles of core-shell nanoparticles organized with Langmuir-Blodgett technique demonstrated attractive sensing performances towards H2 and NH3 in extended concentration ranges.
Another important contribution concerns the elucidation of the sensing mechanisms. Various analytical techniques including Temperature Programmed Desorption, Temperature Programmed Reduction and Microcalorimetry were used to allow the discussion of the sensing performances towards mechanisms.

Figure 1
A Three Electrode Mixed Potential Sensor for Gas Detection and Discrimination
Authors: Tsui Lok-kun , Benavidez Angelica D , Palanisamy Ponnusamy , Evans Lindsey , Garzon Fernando H 
Published: February 2020

Mixed potential solid state electrochemical sensors potentially serve as devices for detection of pollutants from industrial and automotive exhaust and can screen dangerous explosive chemicals in security sensitive areas. In these sensors the difference in catalytic activity between two electrode materials produces a voltage from the difference in the mixed potential that is established at steady state. By integrating multiple electrodes on a single substrate, each pair tuned to be sensitive to different gases, a device can be produced which is selectively sensitive to a variety of gases.
The three-electrode sensors were fabricated by ESL ElectroScience with a high temperature co-firing technique on an insulator-YSZ-insulator substrate and Pt, La0.8Sr0.2CrO3 (LSCO), and Au0.5Pd0.5 electrodes were applied by screen printing. A porous YSZ layer over the electrodes serves as the electrolyte, and a length of Pt is printed on the back to serve as an integrated heater. The heating is applied by a control board which imposes a constant resistance, maintaining the temperature during the testing at various flow rates. The sensors were tested at 450-500oC in a 10% O2 atmosphere to different test gases which include NOx, CO, C3H8, (Figure 1) and mixtures of these gases. The Au/Pd+Pt pair is found to be most sensitive to NOx and CO, the LSCO+Pt pair is most sensitive to NOx and C3H8, and the Au/Pd+Pt pair is sensitive only to CO. Against 50-200 ppm backgrounds of NOx and C3H8, the introduction of 100 ppm CO to the gas stream yields a 30 mV response on the Au/Pd+Pt and Au/Pd+LSCO pairs, but produces less than 10 mV shift on the LSCO+Pt pair. Once sets of data consisting of voltage responses to blends of gases were collected, we successfully trained artificial neural networks to associate voltage responses with both binary gas mixture ratios and absolute concentrations of gases, as well as identify which mixtures of gases were present.
Figure 1. Response of the three-electrode sensor at 450oC to different gases, where a preferential selectivity towards CO is seen in Au/Pd+Pt or Au/Pd+LSCO pairs and a selectivity towards C3H8 is seen in LSCO+Pt.

Figure 1