bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Stable Carbon-Free Cathode for Rechargeable Lithium-Oxygen Battery with Long Cycle Performance
Authors: Song Shidong , Yan Pengfei , Liu Bin , Bowden Mark E , Engelhard Mark H , Wang Chongmin , Xu Wu , Zhang Jason 
Published: February 2020

Lithium-oxygen (Li-O2) batteries have extremely high theoretical specific capacities and energy densities than Li-ion batteries. It is estimated that a practical Li-O2 battery could provide 3-5 times gravimetric energy density of conventional Li-ion batteries. The cathode active material (oxygen) is not stored in the Li-O2 battery and can be obtained from the environment outside the batteries. However, the cycle performances of these Li-O2 batteries are still limited by the stability of the air electrode and the electrolyte. Carbon-based electrodes are believed to decompose during charge and promote electrolyte decomposition as well. The fabrication of a stable and highly active carbon-free cathode for both the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) becomes a great challenge at present for the development of rechargeable Li-O2battery.
Recently, some carbon-free cathode materials have been reported, including noble metals,1 oxides,2 and carbides.3 Metal oxides have low conductivities and are mainly utilized at low current densities. Noble metals show outstanding performance but may not be applicable due to the high cost and high density. Carbides can achieve good bi-functional activities for ORR and OER and be with low cost. However, only TiC was reported to achieve high cycle performance as a carbon-free cathode for Li-O2 batteries so far. Here we report the application of a novel material for the carbon-free cathode of Li-O2 batteries. The battery can be stably operated for more than 200 cycles with a stable voltage profile under the capacity-limited condition. With the aid of structure and composition characterizations, the mechanism of discharge and charge process is also investigated. This novel material is very promising for the use as an alternative carbon-free cathode, as well as for studying and exploring the stable electrolyte in rechargeable Li-O2batteries.

Acknowledgements

This work was supported by the Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Vehicle Technologies, the Advanced Battery Materials Research Programs of the U.S. Department of Energy (DOE). The microscopy and spectroscopy measurements were performed at the Environmental Molecular Sciences Laboratory, a national scientific user facility sponsored by the DOE’s Office of Biological and Environmental Research and located at Pacific Northwest National Laboratory.

References

Z. Peng, S. A. Freunberger, Y. Chen, P. G. Bruce, A Reversible and Higher-Rate Li-O2 Battery, Science., 337, 563 (2012).

M. M. O. Thotiyl, S. A. Freunberger, Z. Peng, Y. Chen, Z. Liu, P. G. Bruce, A stable cathode for the aprotic Li-O2 battery, Nature Materials, 12, 1050 (2013).

F. Li, D.M. Tang, Y. Chen, D. Golberg, H. Kitaura, T. Zhang, A. Yamada, H. Zhou, Ru/ITO: A Carbon-Free Cathode for Nonaqueous Li-O2 Battery, Nano Lett., 13, 4702 (2013).
A High-Performance Magnesium Rechargeable Battery Enabled By a Mgcl-Ion Storage Mechanism
Authors: Yoo Hyun Deog , Yao Yan 
Published: February 2020

Magnesium rechargeable batteries have recently attracted attention because of the large theoretical volumetric capacity, dendrite-free deposition/stripping behaviour, and earth-abundant Mg resources. However, the sluggish diffusion of Mg2+ in host materials has so far limited the choice of cathodes to Chevrel-phase molybdenum chalcogenide that has Mg-ion storage capacity around 100 mAh g–1. Here we show that a high-performance magnesium rechargeable battery enabled by a MgCl-ion storage mechanism using two-dimensional TiS2 with an interlayer spacing expanded up to an unusually large value of 1.86 nm (327% as large as the pristine form) can deliver a high reversible capacity of 270 mAh g–1 and an exceptional rate performance of 100 mAh g-1 at 5C-rate. We anticipate that this discovery will lead to novel mechanisms and material designs for multivalent ion storage, which could open the way to high-energy-density, low-cost and safe batteries.
Probing Polysulfide Shuttle Effect in the Li-S Battery
Authors: Mistry Aashutosh , Chen Chien-Fan , Liu Zhixiao , Mukherjee Partha P. 
Published: February 2020

The lithium-sulfur battery is a strong contender among the beyond Li-ion chemistries due to its superior capacity and energy density as compared to the conventional Li-ion cells.
However, experimental evidences suggest that even the first discharge capacity is appreciably lower than the theoretical limit. This non-ideality is usually associated with the so-called “polysulfide shuttle effect”. On the cathode side, solid sulfur dissolves in the electrolyte and undergoes successive reduction to different intermediate and reduced-order sulfide ions. Due to the underlying potential and concentration gradients, these negative ions travel toward the anode and chemically oxidize the lithium metal, while being reduced simultaneously. Theoretical capacity is achieved when sulfur undergoes complete electrochemical reduction; hence the above chemical reaction(s) limit the available capacity.
Lithium sulfide (Li2S) is the final discharge product which forms when the ionic product exceeds the solubility limit. This can passivate the surface, block the porous structure and may lead to the reacting species starvation in the cathode.
The shuttle effect is a resultant manifestation of these coupled phenomena. In this work, a computational study is presented in order to quantify the influence of shuttle effect on the Li-S cell capacity. The model correlates concentration evolution and microstructural changes with cell performance. Based on this understanding, electrode modifications such as, cathode coating and microstructure properties are studied in order to fundamentally understand the deleterious influence of the “shuttle effect” on cell performance.

Figure 1
Combined Battery/Supercapacitor Hybridised Energy Storage Systems for Hybrid Electric Vehicles
Authors: Sarwar Wasim , Offer Gregory James , Gopalakrishnan Krishnakumar , Green Nick 
Published: February 2020

Automakers are striving to increase electric vehicle driving range without compromising performance and simultaneously reducing charging times. However, this requires an increase of both the energy and power density of the Energy Storage System (ESS); though in battery design these two attributes are generally mutually exclusive therefore a compromise must be made. It is hypothesised that a Hybridised Energy Storage System (HESS) consisting of Supercapacitors (SC) and high energy density batteries in parallel with no DC/DC converter could result in an ESS with improved energy and power density in comparison to an ESS consisting of batteries only.
To enable automotive engineers to design such systems we have created a toolset (i.e. models) that can accurately reproduce the behaviour of such a HESS, in particular, the interactions between the battery and SC. Further, the tool is valid over a range of conditions known to affect system performance such as temperature. The tools are also validated with experimental data where the individual contributions of the battery and SC can be assessed.
A high-fidelity physically meaningful electrical Equivalent Circuit Model (ECM) of a supercapacitor is combined with a physical pseudo-3D thermal model. Separately, a physics-based battery model is generated and parameterised for an NCA 18650 cell. Model order reduction techniques are used to obtain an acceptable simulation time, resulting in a physics-informed electrical ECM which is subsequently coupled with a high-fidelity thermal model. Both models are individually validated across a range of operating conditions including temperature and current. The validated models are paired and the HESS model is validated over an automotive drive cycle with a particular emphasis placed upon battery current and temperature evolution. The generated toolset demonstrated that a HESS can provide superior performance to a battery only system for particular applications, however power availability limitations can cause highly detrimental effects for incorrectly sized systems, and hence good system design is critical.

Figure 1
Applied Single Particle Measurement Technique for One Si Particle
Authors: Nishikawa Kei , Li Chunyan , Kanamura Kiyoshi 
Published: February 2020

Si is very attractive material for next-generation negative electrode of Li batteries, because of very large capacity. However, Si has very large volume change during the lithiation and delithiation. Such large volume change induces very rapid electrode degradation. There are many researches for the restriction and accommodation of the volume change of Si based materials [1]. Also, in-situ TEM observation technique has been utilized to understand the lithiation and delithiation mechanism of nano-sized Si particles [2]. In-situ TEM technique is very powerful technique, however it needs high vacuum condition or no vapor pressure liquid like ionic liquids. It is also very important to find the electrochemical characteristics in actual electrolytes system. Single particle measurement technique is very useful to reveal the intrinsic electrochemical characteristics of a micro-scale particle in commercial Li-ion battery electrolytes. In this study, the single particle measurement technique is used to understand the volume expansion mechanism of a micro-size Si particle in the first lithiation reaction.
The detailed experimental conditions for the single particle measurement were described elsewhere [3]. After the electrochemical characterization, the lithiated Si particle was picked-up by micro-tweezers in order to transfer the particle to other analytical equipment, for example, SEM, FIB-SEM, TEM and micro-Raman. In this study, the relationship between the volume expansion behavior of a micro-sized Si particle and the morphological and structural variations is focused. Figure 1 shows the drastic volume expansion behavior of a Si particle during the first lithiation and the charging curve. The measured apparent volume expansion ratio is much larger than the theoretical values [3, 4]. The Si powders used in this study is composite of crystalline and amorphous Si, and micro-sized secondary particles are composed of several hundred nm primary particles. Therefore, the Si particle used in this study may have the space inside the secondary particle. Furthermore, Cui et al. have reported the crystalline Si shows the anisotropy volume expansion during the lithiation. Such anisotropy volume expansion may induce the extraordinary apparent volume expansion. In order to reveal the volume expansion of a Si particle, ex-situ SEM, TEM observation was conducted. Fig.2 shows TEM images of cross section of the lithiated Si particle. The images show the lithiated Si is mainly amorphous phase, and only a very small parts remain crystalline Si phase. It is caused by the local electrical disconnection because of very large volume expansion. The TEM observation also shows surface SEI layer composition. The detailed results will be shown in the presentation.
[1] M. Wu, et. al., J. Am. Chem. Soc., 135 (2013) 12048
[2] M. T. McDowell, et al., Nano Lett., 13 (2013) 758-764
[3] K. Nishikawa, et. al., J. Power Sources, 243 (2013) 630
[4] K. Nishikawa, et al., J. Power Sources
302 (2016) 46

Figure 1
Important Roles of Crystallinity in Voltage Fade of Li- and Mn-Rich Cathodes Exemplified By Li2Ru0.5Mn0.5O3 Studies
Authors: Yang Xiao-Qing , Hu Enyuan , Lyu Yingchun , Han Lili , Bai Jianming , Dooryhee Eric , Yu Xiqian , Li Hong , Xin Huolin L. 
Published: February 2020

Abstract: Li- and Mn-rich cathode materials have been considered as promising candidates for application of lithium-ion batteries in vehicles due to their high capacity and high energy density (capacity around 250 mAh/g). However, these materials suffer from a serious problem of voltage fade. The average discharge voltage keeps decreasing as the cycling goes on and results in decreased energy output after limited cycles. In order to solve this problem, many efforts have been put in to understand the origin of such phenomenon, mostly from structural and chemical points of view. In this work, the important roles of crystallinity, or the microstructure of the cathode material in voltage fade are studied. The study is carried out on Li2Ru0.5Mn0.5O3 as an example. The material is electrochemically prelithiated to around Li3.2Ru0.5Mn0.5O3 first and then delithiated to Li2Ru0.5Mn0.5O3 . It is shown that even though the crystal structure mostly remains the same, the crystallinity is severely damaged by breaking the sub-micro domains into very fine nano-sized domains. Such loss of crystallinity causes much more significant voltage fade in the following cycling compared with those normally cycled samples. The more severe voltage fade caused by low crystallinity can be attributed to the accelerated oxygen loss due to the increased defects and surface area of the prelithiated sample. These results indicate the great importance of crystallinity of the cathode materials.

Acknowledgement

The work at Brookhaven National Laboratory was supported by the U.S. Department of Energy, the Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Vehicle Technologies under Contract No. DE-SC0012704. Use of the National Synchrotron Light Source II (NSLS-II) and Center for Functional Nanomaterials at Brookhaven National Laboratory were supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contracts No. DE-SC0012704.
Benefits of Water-Based Binder Electrodes for Li-Ion Batteries
Authors: Buqa Hilmi , Wussler Sabine , Studenik Erika , Melin Irina , Deghenghi Gianluca , Blanc Pierre 
Published: February 2020

Leclanché implements the innovative water-based production process; applied to all cell electrodes, it results in cost effective large format 30Ah LTO- and 43 Ah graphite-based cells, while minimizing environmental impact of manufacturing and ensuring very high cell performances and lifetime stability.
Some of the benefits of water-based binder electrodes are:

No more usage of organic (toxic) solvents in the mixing and coating processes.

Reduced manufacturing cost of aqueous vs. solvent processing. Elimination of expensive solvent recovery steps, reduction of capital cost for coating equipment and elimination of expensive inactive components.

Simplification of machinery (no EX requirements). Machinery size reduction (water extraction is faster than NMP one, therefore the drying section for coating line is reduced).

Fast drying speed and low drying temperature require less electric power and yield to higher production rate.

No dry room required for cell assembly, only humidity control is required during electrolyte filling, etc.

The innovative high-quality manufactured electrodes lead to very high mechanical and electrochemical stability during cycling, e.g. Leclanché large-capacity LTO lithium-ion batteries allow for tenths of thousands full-DoD cycles to be reached, even in highly demanding conditions (see Fig.1). The lifetime estimation exceeds 20.000 cycles and is little affected by C-rate.

Fig. 1: Lifetime characteristics at RT (21°C); influence of C-rate and lifetime estimation of 16 Ah cell

Figure 1
Addressing Reliability and Safety Issues on Battery Systems Via Quantitative Analyses and Validation
Authors: Liaw Bor Yann 
Published: February 2020

As advanced batteries continue to grow in the sectors of electrifications of transportation and energy storage systems, risk management by the stakeholders has also become an emerging topic of concerns. To date, the practical approach in addressing such concerns has not been fully understood and implemented. One of the impediments is the lack of full appreciation of the complexity involved in handling the issues in the research community and need of technical competency in addressing them. The industry does not really have the luxury to learn from the hiccups and disasters of fire and explosion incidents to calm the anxiety from the consumers in the expectation of reliable and safe products in the marketplace, while we continue to learn from the mistakes and manage the risks in the “green energy transformation.”
Batteries have some unique aspects that traditionally mechanical and electrical devices need not to pay attention to: performance degradation by aging and its path dependency. This unique aspect makes the battery management of performance, including risks, much more difficult than usual. Not only the initial properties of the battery systems need to be compatible for manufacturing processes without trading off performance, but also the consequences of aging and degradation during operations need to be managed to endure reliability and safety challenges. Worse than that, those system properties are often affected by the environment they operate. Therefore, matured battery designers need to familiarize not only battery systems’ capability but also the nature of the environments and the operating conditions to cater in their designs. To understand such causality in battery design is inherently challenging. This is something needs to be overcome to address battery reliability and safety issues. This is why battery system diagnostics and prognostics are pivotal to addressing the battery reliability and safety issues.
Battery diagnostics and prognostics are a vital part of the solutions to deal with this situation. Through proper diagnostic and prognostic analyses, one can extract useful information from the failure analyses (FA), including failure mode and effect analyses (FMEA). However, for these analyses to be feasible in battery research, it requires additional efforts to ensure accurate and precise information being extracted from the analyses in a quantitative manner, which is not commonly practiced in the industrial and the research communities. Here, the issues with quantitative diagnostic and prognostic analyses are discussed and explained; using practical examples in some of the abuse studies to illustrate the critical aspects of such analyses with mechanistic understanding.
Investigation of Fluorophosphate Cathode Materials for Na Ion Batteries By Ex Situ
23 Na Solid-State Nuclear Magnetic Resonance
Authors: Smiley Danielle L. , Goward Gillian R. 
Published: February 2020

Sodium ion batteries have experienced a renaissance in recent years owing to the low cost and high abundance of sodium relative to lithium resources.1 Despite this renewed attention, there remains a need to realize sodium electrode materials that are suitable for commercial applications. In light of this, there is significant motivation to identify and analyze various properties of novel electrode materials, including structural and ion diffusion changes that occur during the electrochemical cycling process.
Solid-state nuclear magnetic resonance (ssNMR) is implemented here in an attempt to characterize structure and site-specific ion mobility in the fluorophosphate family of cathode materials (Na2MPO4F), as they are known to exhibit high thermal and electrochemical stability.2,3
Ex situ
23Na NMR studies at fast magic angle spinning (65 kHz) allow for sufficient spectral resolution to observe local changes at unique Na environments in these paramagnetic electrode materials.
Na atoms housed in the two crystallographically unique positions in the layered Na2FePO4F phase are distinguishable via this technique (Figure 1a), offering the opportunity to probe local properties in the pristine phase. Further, by incorporation of this material into a sodium ion cell, the changes to the 23Na NMR spectrum can be correlated ex situ to structural changes directly resulting from the electrochemical (de)intercalation process. The appearance and relative increase of two new Na peaks in the NMR spectrum (Figure 1b) upon electrochemical desodiation of the material suggests that Na atoms in both crystallographic environments may in fact be mobile despite an apparent lack of chemical exchange between sites. These new Na resonances can be assigned to the partially oxidized variant of the pristine material, where the dramatic shift in peaks in the NMR spectrum is attributed to the change in electron configuration of the transition metal from Fe2+ to Fe3+. Ongoing efforts to quantify the diffusion of Na ions and characterize the mechanism of electrochemical desodiation will be presented.

References:

(1) Palomares, V.; Serras, P.; Villaluenga, I.; Hueso, K. B.; Carretero-González, J.; Rojo, T. Energy Environ. Sci.
2012, 5(3), 5884.
(2) Ellis, B. L.; Makahnouk, W. R. M.; Rowan-Weetaluktuk, W. N.; Ryan, D. H.; Nazar, L. F. Chem. Mater.
2010, 22(3), 1059.
(3) Ellis, B. L.; Makahnouk, W. R. M.; Makimura, Y.; Toghill, K.; Nazar, L. F. Nat. Mater.
2007, 6 (10), 749.

Figure 1
Interface Storage and Diffusion in Titania-Based Na-Ion Battery Negative Electrodes
Authors: Hanzu Ilie , Prutsch Denise , Uitz Marlena , Wilkening Martin 
Published: February 2020

Ordered, nanostructured transition metal oxides are currently in the spotlight of battery research. To exploit, however, the full potential of self-assembled titania nanotube layers in Na-ion battery technology we need to close the gap in knowledge about the underlying storage mechanisms as well as ion dynamics. For this purpose, amorphous TiO2 nanotubes (70-130 nm in diameter, 4.5 – 17 µm in length) were fabricated by anodization, i.e., electrochemical oxidation. The electrochemical behaviour with respect to sodium insertion was studied by cyclic voltammetry and galvanostatic cycling with potential limitation. It turned out that the nanotubes are very resilient to cycling, some being able to withstand more than 300 charge-discharge cycles without significant loss of capacity. Compared to classical insertion reactions, the mechanism of reversible electrochemical storage of Na+ in the nanotubes seems to differ significantly. There is strong evidence that a large amount of the Na+ ions is stored on the surface or in the surface-influenced regions while only a smaller fraction is inserted in the walls of the tubes. The interfacial Na+ storage is governed by a faradaic adsorption phenomena, which is essentially different from the (pseudo-)capacitive model hitherto used in the literature. The finding that, in the case of sodium, interfacial storage is more important than ion insertion into the crystal lattice is supported by the very low Na+ diffusion coefficients determined at various electrode potentials (in the order of 4 · 10-20 - 10-21 cm2/s). This dominant interfacial storage mechanism may explain the high specific capacity and the very good cycling performance recently reported for some nanostructured titania phases as well as for other nanosized titanate materials.

Figure A. Chemical diffusion coefficient of Na+ into amorphous TiO2 at room temperature (23 ±1°C) after subtracting the interfacial storage contributions for different sample types. Figure B. Pseudo-capacitance values corresponding to the interfacial storage of Na+ ions on various nanotube layers plotted as a function of the electrode potential.

Figure 1