bluuebunny/crossref_metadata_2025 huggingface dataset:
Na Ion Batteries: A Promising Candidate for Large-Scale Energy Storage
Authors: de la Llave Ezequiel , Borgel Valentina , Park Kang-Joon , Hwang Jamg-Yeon , Sun Yang-Kook , Hartmann Pascal , Chesneau Frederick Francois , Aurbach Doron
Published: February 2020

The demand for inexpensive and effective energy storage technologies is rapidly increasing. The imminent exhaustion of fossil fuel resources and the environmental consequences related to their use, combined with the rapid expansion of renewable energy sources, promote the scientific community to develop advanced energy storage systems. Among the several technologies that are suitable for large-scale energy storage, Sodium-ion batteries (NIB) appear as one of the most appealing options. Sodium natural resources are unlimited everywhere, as sodium is the fourth most abundant element on earth. Additionally, sodium is the second-lightest and smallest alkali metal next to lithium. Indeed, research in this area, reflected in the number of publications, has dramatically increased since 2011.

We will describe a completed study on sodium-ion batteries. With the aim to offer a comprehensive view, we compared all the Na-ion systems studied herein to similar Li-ion systems. Na-ion and Li-ion full cells were investigated, using hard carbon as the anode material, NaNi0.5Mn0.5O2 and LiNi0.5Mn0.5O2 as the cathodes.

A comprehensive description and discussion of the possible use of hard carbons as anode is presented [1]. We explored storage mechanisms, cycling, stability, surface chemistry, and impedance behavior. We examined the choice of the binders, solvent and additives on the electrodes’ performance. The critical effect of the hard carbon anodes pretreatment on the total capacity and stability of full cells will be discussed.

We also offer a detailed description of the structure, phase transition, electrochemical behavior and kinetics of the NaNi0.5Mn0.5O2 cathodes, including interesting comparison with their lithium analog [2]. Using impedance spectroscopy in three electrodes cells we show that the full cell impedance is dominated by the contribution of the cathode side. We discuss possible reasons for capacity fading of these systems, in connection to the cathode’s structure and relevant surface phenomena.

References

1. E. de la Llave, V. Borgel, E. Zinigrad, F. F. Chesneau, P. Hartmann, Y-K. Sun, D. Aurbach, Study of the Most Relevant Aspects related to Hard Carbons as Anode Materials for Na-ion Batteries, Compared to Li-ion Systems. Isr. J. Chem. (2015), 55, 1260-1274. 

2. E. de la Llave, V. Borgel, K.J. Park, J.Y. Hwang, Y.K. Sun, P. Hartmann, F. Chesneau and D. Aurbach, Comparison between Na-ion & Li-ion Cells: Understanding the Critical Roles of the Cathodes Stability and the Anodes Pretreatment on the Cells Behavior, ACS Applied Materials & Interfaces (2015), DOI: 10.1021/acsami.5b09835
The Structural Effect of PdCu Nanocatalysts on Catalytic Activities for Rechargeable Lithium-Oxygen Batteries
Authors: Park Mihui , Song Kyeongse , Kim Soo Young , Kang Yong-Mook
Published: February 2020

Palladium-copper (Pd-Cu) alloys have two representative crystal structures; one is body-centered cubic (bcc), the other is face-centered cubic (fcc) even though both Pd and Cu originally have fcc crystal structures. The fcc Pd-Cu alloys have disordered structure within which Pd and Cu atoms are positioned randomly in the fcc lattice whereas the bcc Pd-Cu alloys have ordered structure which consists of alternative layers with single component either Pd or Cu atoms. In order for tailoring design of Pd-Cu alloys, controlling the physical and chemical characteristics of the alloys has been investigated extensively.

Pd-Cu alloys have been widely utilized as catalysts for the hydrogenation of carbonyl compounds, for the reduction of nitrates and nitrites in water, for the oxidation of formic acid in direct formic acid fuel cell, as membrane for hydrogen separation and so on. In particular, bcc Pd-Cu alloys have occasionally shown superior performance to fcc Pd-Cu alloys. For an example of hydrogenation of acetylene, bcc Pd-Cu alloy have better ethylene selectivity than fcc Pd-Cu alloys, because isolated Pd atoms on the surface of bcc Pd-Cu alloys increase selectivity in the hydrogenation of acetylene. Most bcc Pd-Cu alloys have been synthesized by annealing of fcc Pd-Cu alloys, which leads to structural transformation and particle growth. Obtaining same sizes of fcc and bcc Pd-Cu alloys is difficult to achieve because crystallites larger than 20 nm favour the ordered bcc structure with lower symmetry. Thus, bcc Pd-Cu alloys in nanoscale have been rarely reported moreover, comparison of fcc and bcc Pd-Cu in nanoscale has been never demonstrated to date.

In this study, we successfully synthesized fcc and bcc Pd-Cu alloys in nanoscale by polyol process with same composition and particle size, furthermore we adopt fcc and bcc Pd-Cu alloys as cathode catalysts for lithium-oxygen batteries. This work would be the first time to compare the catalytic activities between fcc and bcc Pd-Cu alloys in nanoscale.
Lithium Nitrate in Rechargeable Lithium-Sulfur Batteries: Catalytic Feature of Redox Shuttle Suppression
Authors: Ding Ning
Published: February 2020

A big breakthrough in the study of rechargeable Li-S batteries was the discovery of LiNO3 additive in 2008, which effectively suppresses LiPSs redox shuttle and enables real rechargeable Li-S batteries. The role of LiNO3, according to conventional understandings, was to react with lithium anode in a controlled way to form a LiNxOy passiviation layer on the anode which prevents the reduction of polysulfide thereon. This understanding, however, is seeing more challenges. Recently, Dr. Sheng S. Zhang of US Army Research Lab detected progressive reduction of LiNO3 on Li anode accompanied by the gradual increase of internal resistance in Li-S batteries. This finding is a direct challenge to the claim that LixNOy layer on anode prevents the LiPSs reduction thereon, as LiPSs with higher reduction voltage (2.1 V) are more easily to be reduced than LiNO3 (1.7 V). The unclear mechanism of redox-shuttle suppression and limited understanding on the impact of LiNO3 have hampered the development of Li-S batteries with long-term cycling stability, despite huge efforts and encouraging progress made in the engineering of nanostructured sulfur cathode reported in a large number of high impact journal publications.

In this manuscript, we revisit some key factors that influence LiPSs redox shuttles, clarify the roles of LixNOy passivation layers, and propose a new mechanism that redox shuttle suppression in the presence of LiNO3 is due to strong binding between the soluble high-order LiPSs and nitrate (NO3
–) anions adsorbed on carbon substrate, which promotes the oxidation of polysulfides to sulfur on charging. This is supported by density functional theory (DFT) calculations and NO3
–-induced low self-discharge rate in Li-S batteries. As the progressive reduction of LiNO3 compromises long-term cycling stability of Li-S batteries by gradual increase of the internal resistance, we propose the substitution of soluble LiNO3 with solid oxide catalyst of good polysulfide oxidation reaction (PSOR) activity, to which ruthenium oxide was found as a preferable choice. This new understanding on the role of LiNO3 is opening a new research path to the development of nanostructured polysulfide oxidation catalysts with fine-tuned composition and morphology to boost the performance of Li-S batteries holistically.
Electrodeposited Three-Dimensional Porous Ru/RuO2 Foam Cathode for Rechargeable Lithium–Oxygen Batteries
Authors: Suk Jungdon , Kwak Kyoung Hwan , Kang Yongku
Published: February 2020

Among many cathode materials explored for lithium-oxygen cathode, carbons are often used because they help achieve high discharge capacities and good ORR performance.  However, most lithium-oxygen batteries containing carbon electrodes suffer from a low round-trip efficiency, low rate capability, a poor cycle life, and electrolyte instability. In this poster, we report a binder- and carbon-free, 3D porous Ru and RuO2 foam cathode for lithium-oxygen batteries. The cathode was simply fabricated by three-step process; co-electrodeposition, electrochemical dealloying and heat treatment process. Both 3D porous Ru and RuO2 dendritic foams have lots of cavity and pits which provide a large surface area for catalytic sites and buffer spaces for the morphological volume stress by the formation/decomposition of Li2O2 during the cycling process. Moreover, both dendritic foams provide a facile electron pathway, a short ion diffusion length, a rapid transport channel for oxygen and electrolytes, and numerous catalytic sites for high electrochemical performance. 3D porous Ru and RuO2 foam cathode delivers a discharge capacity of 1570 mAh/g and 4900 mAh/g at 50 mA/g and can be recharged for OER under low charge voltage with good reversibility and cyclability. We systematically investigated the reversibility and cyclability of a lithium-oxygen battery using the 3D porous Ru/RuO2 foam cathode using scanning electron microscopy (SEM), X-ray diffraction (XRD), selected area electron diffraction (SAED), in-situ Differential Electrochemical Mass Spectrometry (DEMS) and FT-IR spectroscopy. The results using the 3D porous nanostructured electrodes in our study represent a promising approach for high-performance electrodes which are compatible with scaled-up manufacturing process for next-generation lithium- air batteries due to their simple and rapid fabrication process.
A Quantitative Tool to Predict the Phase Composition of Lithium-Sulfur Batteries
Authors: Dibden James William , Garcia-Araez Nuria , Smith John William , Owen John R.
Published: February 2020

Energy is essential in modern society, however ensuring that it is both affordable and environmentally benign presents a major challenge. Electrical energy storage is important in overcoming these issues; grid energy storage and electric cars being some of the primary uses. Lithium-sulfur (Li-S) batteries are one of the most promising candidates in next generation electrical energy storage, possessing a theoretical specific energy of 2600 W h kg-1.1 Several other advantages of using sulfur as the positive electrode include its abundance, low cost and non-toxicity. The complete reduction of sulfur (S8) to lithium sulfide (Li2S) occurs via a multistep reaction pathway, which has been the subject of much debate. Unlike the lithium-ion (Li-ion) battery, the discharge/charge reactions do not occur in the solid state but rather electron transfer occurs between the carbon positive electrode interface and the various sulfur species dissolved in the electrolyte. Due to the high solubility of the intermediate polysulfides species, several technical challenges exist that have hindered Li-S battery commercialization, including the widely reported shuttle mechanism.2 In addition to their high solubility, the intermediate polysulfide species are only stable in solution, sensitive to moisture and are known to disproportionate/comproportionate to a variety of polysulfides that change further on dilution.3 In order to overcome these issues, a better understanding of the polysulfide composition in the electrolyte, their concentration and the number of phases present is required.

We have developed two techniques, one which is able to determine the concentration of dissolved polysulfides in terms of the total sulfur content [S] and the other is able to determine the average oxidation state of the sulfur species, between S0 (as S8) and S2- (as Li2S). To determine the concentration of sulfur species present in the electrolyte, gravimetric analysis has been performed exploiting the low solubility of barium sulfate (BaSO4). To determine the average oxidation state of sulfur species, a redox titration has been developed. Using these methods and the information obtained, it is possible to develop a ternary phase diagram between S, Li2S and the electrolyte. This can be used to predict phase boundaries and determine the appearance of Li-S discharge profiles. The figure shows the proposed ternary phase diagram with the phases and degrees of freedom stated as determined using Gibbs’ phase rule: Freedom = Components – Phases, at fixed temperature and pressure.

[1] P. G. Bruce, S. A. Freunberger, L. J. Hardwick and J. M. Tarascon, Nat. Mater., 2012, 11, 19-29.

[2] S. M. Al-Mahmoud, J. W. Dibden, J. R. Owen, G. Denuault and N. Garcia-Araez, J. Power Sources, 2016, 306, 323-328.

[3] D. Zheng, X. R. Zhang, C. Li, M. E. McKinnon, R. G. Sadok, D. Y. Qu, X. Q. Yu, H. S. Lee, X. Q. Yang and D. Y. Qu, J. Electrochem. Soc., 2015, 162, A203-A206.

Figure 1
Ex-Situ Synchrotron X-Ray Studies of Alpha-Type Manganese Dioxide Nanorod Cathode in Zinc-Ion Battery
Authors: Alfaruqi Muhammad Hilmy , Nam Sukyung , Gim Jihyeon , Song Jinju , Kim Sungjin , Mathew Vinod , Jo Jeonggeun , Lee Seulgi , Islam Saiful , Kim Jaekook
Published: February 2020

Nowadays, extensive researches to overcome the world energy crisis has emphasized the urgent necessity of developing sustainable energy storage systems. The rechargeable lithium-ion battery (LIB) dominates today's battery market for portable device applications. Nonetheless, the crucial issues concerning its safety, eco-friendliness, and cost-effectiveness, as well as the controversies associated with the availability of lithium resources, have led to the continuous exploration of new battery chemistries. Sodium-ion, potassium-ion, and aluminum-ion batteries are promising alternative since these devices are based on relatively abundant and cheap sodium, potassium, and aluminum elements, respectively. However, these battery systems also suffer from complicated issues of safety, processing costs, and environmental concerns. Earlier efforts for developing a rechargeable aqueous zinc-ion battery (ZIB), which facilitates energy storage application via zinc-ion insertion/extraction, has opened the way for the realization of safe, environmentally benign and cost-effective next generation energy storage system. ZIB is still in the stage of early phase of development, therefore, fundamental studies concentrating on the zinc-ion insertion mechanism is an attractive goal to pursue. In this work, we used nanorod alpha-type manganese dioxide cathode for ZIB application. Alpha-type manganese deioxide was prepared by a simple hydrothermal synthesis. SEM and TEM studies showed rod-type sample with approximately 20 and 200 nm of width and length, respectively. The nanorod cathode exhibited an initial discharge capacity of 176.8 mAh g-1 at a current density of 83 mA g-1 and demonstrated nearly 100% Coulombic efficiencies under prolonged cycling when tested for zinc storage properties. Rate performance measurements revealed that specific capacities of 43.33 and 31.48 mAh g-1 were registered at current densities as high as 1333 and 1666 mA g-1. A combination of ex-situ synchrotron XRD and XAS studies confirmed the reversibility of electrochemical zinc-ion insertion into [2x2] tunnels of the alpha-type manganese dioxide host structure. The host exhibits structural stability by accommodating an unit cell volume expansion of approximately 3.12% during Zn-insertion. The present study hence paves the way for further development of rechargeable aqueous ZIB as an alternative ideal energy storage system due to its excellent safety and reliability.

Figure 1
Electrochemical Analysis in Lithium-Sulfur Batteries Using Carbonaceous Materials
Authors: Park Jungjin , Kim Chunjoong , Sung Yung-Eun
Published: February 2020

Recently, the expansion of energy consumption of high technology devices and the requirement of nature-friendly energy sources make a necessity of new conceptual energy source. Notably, among various approaches for new energy sources, electrochemical energy storage system seems appealing for its high efficiency and low product of pollutant. Lithium-sulfur secondary battery is one of the most promising electrochemical system for storage chemical energy directly to electrical energy. Although a plenty of research has been conducted in this field, several issues remain, including the irreversible loss of polysulfides and low electrical conductivity.

In this talk, carbonaceous materials are carefully introduced for analyzing electrochemical performance in lithium sulfur battery; not only increasing electrical conductivity for fast kinetics and but also anchoring soluble polysulfides for reversible redox reactions. In addition, the carbon-sulfur bonds originated from oxygen functional groups and polymeric sulfides shows that can support the effective polysulfides affinity with carbon, those effects are proved from various advanced measurements and electrochemical analyses based on theoretical model. These considerations can support tailoring cathode design to solving limitations in lithium-sulfur battery field.
Copper Oxides As a Hydrogen Fluoride Scavenger for High-Voltage LiNi0.5Mn1.5O4 Positive Electrode
Authors: Soon Jiyong , Kim Hyun-seung , Lee Tae Jin , Jung Jiwon , Lee Jae Gil , Kim Jongjung , Lee Jeong Beom , Ryu Ji Heon , Oh Seung M.
Published: February 2020

1. Introduction

The spinel-structured LiNi0.5Mn1.5O4 (LNMO) is a promising high-voltage (~4.7 V vs. Li/Li+) positive electrode for lithium-ion batteries (LIBs). However, since the working voltage is higher than the electrochemical stability window of common electrolytes (~4.3 V vs. Li/Li+), electrolyte decomposes during cycling. This irreversible reaction causes low Coulombic efficiency. Moreover, hydrogen fluoride (HF) is generated as a result of electrolyte decomposition, which attacks the LNMO electrodes to cause electrode failure. Meanwhile, it is known that HF etches metal oxides, signifying that metal oxides can act as HF scavenger. In this work, copper oxide (CuO) is used as the HF scavenger for LNMO electrodes. The cycle performance of LNMO electrodes is significantly improved at elevated temperature due to the HF scavenging role of CuO.

2. Experimental

The composite LNMO electrode was prepared along with Super-P and PVdF binder, into which nano-sized CuO powder was added. The used electrolyte was LiPF6 dissolved in a mixture of ethylene carbonate (EC), ethyl methyl carbonate (EMC) and diethyl carbonate (DEC). The galvanostatic charge/discharge cycling was performed at 60oC. For X-ray photoelectron spectroscopy (XPS), the cycled LNMO electrodes were disassembled in an argon-filled glove box.

3. Results and Discussion

The CuO-free LNMO electrodes show poor performances. Due to severe electrolyte decomposition at 60oC, the Coulombic efficiency is poorer than that for the CuO-added electrodes. The CuO-free LNMO electrodes also show a larger electrode polarization and rapider capacity fading, all of which seem to be due to the electrode failure caused by HF attack. The outperformance of CuO-added electrodes over the CuO-free ones must be due to the beneficial role of CuO, which can act as a HF scavenger because of its basicity. The adverse effects of HF can be suppressed by removing HF in the electrolyte solution.

4. Reference

1) T. Yoon, et al., J. Power Sources, 215, 312 (2012).

Figure 1
High Energy Density Na-Ion Battery Technology
Authors: Barker Jerry , Heap Richard John , Roche Noel , Tan Chaou , Sayers Ruth , Whitley James , Liu Yang
Published: February 2020

High energy density sodium-ion (Na-ion) batteries are now close to successful commercialization. These energy storage devices offer some significant advantages over their lithium-ion counterparts, such as lower material costs, improved safety characteristics and superior transportation properties [1,2]. In this study we demonstrate the electrochemical performance characteristics of full Na-ion cells constructed using a proprietary layered oxide cathode NaaNi(1-x-y-z)MnxMgyTizO2 and a hard carbon anode material [3].

Figure 1 depicts the voltage profile for a typical Faradion Na-ion cell. The cathode material delivers a reversible specific capacity of over 146 mAh/g and the cell generates an average discharge cell voltage of around 3.2 V. The projected specific energy for this battery system is 140-150 Wh/kg. The cell cycles with low polarization and with excellent columbic and (round-trip) energy efficiency. Figure 2 denotes a typical cycle life plot (100 % DOD) for a representative Na-ion cell. Following 170 cycles the discharge capacity fade is less than 1%. Simple linear extrapolation indicates that this cell should cycle 1000 cycles while maintaining well over 90% of its original discharge capacity.

To demonstrate the commercial viability of Na-ion batteries, Faradion has scaled-up this cell chemistry to the 3 Ah (9 Wh) prismatic pouch cell level. These cells were fabricated using traditional Li-ion manufacturing methods. Multiple prototype cells have been incorporated successfully into E-Bike (>400 Wh) and E-Scooter (>750 Wh) demonstrator packs [4,5]. 

Further performance and safety characteristics of the Na-ion cells will be provided during the presentation.

References:

1.  V. Palomares, P. Serras, I. Villaluenga, K. B. Hueso, J. Carretero-Gonzalez and T. Rojo, Energy Environ. Sci. 2012, 5, 5884. 

2.  J. Barker, M.Y. Saidi and J. Swoyer, Electrochem. Solid-State Chem. 2003, 6, A1 

3.  For example, J. Barker and R.J. Heap, PCT Patent App. WO/2014/057258 (filed October 2013)

4.  J. Barker and C. J. Wright. Presentation at the Advanced Automotive and Stationary/Industrial Battery Conference, AABC, Detroit, Michigan, USA, June 2015

5.  J. Barker, R.J. Heap, N. Roche, C. Tan, R. Sayers. J. Whitley and Y. Liu. Presentation at the 2nd International Symposium on Sodium Batteries, Phoenix, Arizona, USA, October 2015

Figure 1
Flexible Protected Lithium Metal Electrodes for Next Generation Batteries
Authors: Visco Steven J.
Published: February 2020

In the late 1980’s a number of companies and universities were involved efforts to develop and commercialize rechargeable lithium metal batteries. Unfortunately, the formation of high surface area lithium associated with the inefficient stripping and plating of lithium metal in liquid electrolytes doomed the commercial prospects for these battery systems. Not surprisingly, battery developers looked for alternative solutions for the rechargeable battery market, leading ultimately to the commercial introduction of Li-ion technology in 1991. Although Li-ion battery technology has benefited from steady incremental improvements since that time, the market demand for the next generation of disruptive battery technology remains strong. Over the past several years R&D efforts focused on next generation battery technology have covered a broad spectrum of alternative anodes and cathodes as well as the possibility of all solid-state structures and it is not yet clear which of these strategies will lead to commercial success. With regards to lithium-based technologies, there is little doubt that replacing the carbon anode in Li-ion cells with a lithium metal electrode that exhibits highly efficient cycling and safe behavior would lead to a dramatic increase in energy density (Wh/l and Wh/kg). In this presentation we will examine a number of development paths for solid-state anodes, as well as the evolution from Li-ion to safe, rechargeable Li metal batteries.
Oxygen-Rich Binder Improves Vulcanized Polyacrylonitrile Cathodes for Li-S Batteries
Authors: Li Yang , Zeng Qingcong , Gentle Ian , Wang Da-Wei
Published: February 2020

Lithium sulfur batteries have very high theoretical energy density. However, the cyclic stability of carbon-sulfur cathode is seriously hindered by the notorious polysulfide dissolution.

Vulcanized polyacrylonitrile is an alternative to carbon-sulfur cathodes where the carbon and sulfur are covalently bonded resulting in much improved stability. Although water-soluble binders are being used widely to stabilize carbon-sulfur cathodes, we observe here that oxygen-rich water-soluble binder can instead facilitate the high-rate performance of vulcanized polyacrylonitrile cathode. In this study, oxygen-rich water-soluble sodium carboxymethyl cellulose (NaCMC) is selected as binder for vulcanized polyacrylonitrile (PANS) cathode. Comparing with traditional oxygen-free PVDF binder, NaCMC shows a preference in fixing active materials and enabling better surface wettability. A high capacity of 938 mA h/g for sulfur is retained after 450 cycles at 0.9C (1C=1675 mA/g). In addition the capacity from NaCMC electrode at 4.5 C rate reaches 677 mA h/g, which is much higher than that obtained with PVDF binder (nearly zero at 4.5C). Our study here reveals the facilitated redox chemistry of PANS cathode by using oxygen-rich binders. The origin is believed relevant to the affinity of oxygen functional groups to lithium polysulfides in terms of chemical adsorption and interfacial charge transfer.
The Effect of Solid Electrolyte Interphase on the Mechanism of Operation of Lithium-Sulfur Batteries
Authors: Markevich Elena , Salitra Gregory , Rosenman Ariel , Talyosef Yosef , Chesneau Frederick Francois , Aurbach Doron
Published: February 2020

Composite sulfur–carbon electrodes were prepared by encapsulating sulfur into the micropores of highly disordered microporous carbon AC1 with micrometer-sized particles and and carbonized polyacrylonitrile (PAN) cloth. We demonstrated that in bis(fluorosulfonyl)imide (FSI) based ionic liquid and in organic carbonates based electrolyte solutions the performance of the obtained electrodes is governed by the formation of solid electrolyte interphase (SEI) during the initial discharge. In both types of the electrolyte solutions the formation of SEI starts at potentials lower than 1.5V vs. Li/Li+ (Fig.1). We attribute the process of the formation of SEI to the reaction of lithium polysulfides with FSI anions or organic carbonates, respectively. Subsequent galvanostatic cycling is characterized by one plateau voltage profile specific to quasi-solid-state reaction of Li ions with sulfur encapsulated in the micropores in solvent deficient conditions. The stability of the SEI thus formed, is critically important for the effective desolvation of Li ions participating in quasi-solid-state reactions.

We proved that realization of the quasi-solid-state mechanism is controlled not only by the porous structure of the carbon host but also by the nature of the electrolyte solution composition and the discharge cut off voltage value. We showed that the FEC-based electrolyte solution demonstrates improved capacity retention during charge–discharge cycling of S/C composite electrodes compared to the EC-based electrolyte. The obtained results are very promising for the development of SLS batteries with FEC-based electrolyte solution which is in progress.

 The cycling behavior of these cathodes is highly dependent on sulfur loading. Despite cracking of the particles observed due to a large volume expansion of sulfur during the lithiation, the best performance and initial coulombic efficiency at room temperature in FSI-based IL electrolyte solutions were demonstrated by S–AC1 composite electrodes with a sulfur loading of 60 wt%. This sulfur loading prevents the access of electrolyte solution molecules to the micropores, and the quasi-solid-state reaction of Li ions with encapsulated sulfur occurs in a solvent free environment. This insight into the mechanism of operating of S–C composite electrodes provides a new approach to the development of new electrolyte solutions and additives for Li–S cells.

Figure 1
Electrolyte Decomposition in Li-S Cells
Authors: Hagen Markus , Joos Martin , Abert Michael , Fanz Patrik , Tübke Jens
Published: February 2020

Li-S cells are attractive due to their high potential gravimetric energy density, but they achieve only low cycle numbers. A major reason for this is a continuous electrolyte decomposition during cycling. As low electrolyte/sulfur ratios are required for high gravimetric energy density, this electrolyte decomposition reduces the obtainable cycle number to below 50.

 It is therefore extremely important to evaluate, reduce or ideally prevent this electrolyte decomposition by utilizing new electrolyte (additives), separators and protection layers.

Applying in-situ mass spectroscopy, the electrolyte decomposition has been characterized for Li-S cells with lithium metal anode, silicon anode and carbon anode with various electrolyte compositions, electrodes and cycling parameters. Electrolyte cracking leads to gaseous substances, some of which are created continuously while others show a maximum depending on the state of charge. Standard ether-based Li-S electrolytes (e.g. DME:DIOX) are unstable with Li metal anodes and will always limit the obtainable cycle number unless further protection devices are applied.

 The attached figure demonstrates specific gaseous substances created in a Li-S cell during cycling between 1.8-2.6 V at 0.6 mA/cm².

Figure 1
Material Interactions Between Cathode Active Material and Conductive Components in Solid-State Lithium Batteries
Authors: Uhlenbruck Sven , Bünting Aiko , Dellen Christian , Finsterbusch Martin , Tsai Chih Long , Vaßen Robert
Published: February 2020

Today’s conventional lithium ion batteries comprise organic liquid electrolytes, which allow high performance of the batteries, however, also cause problems due to their limited stability. A promising approach to solve these issues is to replace the liquid electrolyte by a ceramic lithium ion conductor thus creating a so-called solid-state battery. Ceramics in general offer a superior chemical and thermal stability compared to any organic material.    

A challenge in solid-state batteries is the processing of a fully inorganic battery cell because of thermally or field activated high-energy treatments that are necessary to create an inherent contact between the functional layers. This work focuses on the interaction and diffusion phenomena of the cathode material LiFePO4 and typical current collector materials like aluminum, titanium, and carbon as a conductive additive. It turned out that the current collector species exhibited high diffusion into and chemical reaction with the cathode material during processing and significantly changed the electrochemical performance of the cathode material. Planar and compact thin-film batteries manufactured by physical vapor deposition (PVD) were used to study this behavior in more detail by scanning electron microscopy, X-ray diffraction, cyclic voltammetry and secondary ion mass spectrometry (SIMS). Especially SIMS benefits from the thin-film approach on planar geometry with smooth surfaces and interfaces, along with pure LiFePO4 cathodes, to identify for example interdiffusion phenomena or chemical reactions.

The capacity of the pure LiFePO4 cathode layers was significantly lower than the theoretical capacity of 170 mAh/g.  LiFePO4 is well known to be a material with extremely low electronic conductivity, and the lower capacity has been also attributed to this issue. Carbon is usually added to this active material to circumvent this drawback, as done with all cathode materials applied in conventional lithium ion batteries. After PVD processing of the cathode material with additional carbon, where carbon was already added to the sputter target, the cathodes had a capacity in the range of the theoretical one. This is not only accounted for a higher electronic conductivity – surprisingly, the microstructure completely changed from an apparently dense layers of LiFePO4 without carbon to a highly porous morphology consisting fibers with dimensions of the order of 100 nanometers with clear spacings of about 100 nanometer between them. As an outlook, these layers could also be used in lithium batteries with liquid electrolyte, featured by apparently continuous LiFePO4 wires instead of LiFePO4 powder stuck together with polymeric binders.
Systematic Investigation of an All-Solid-State Li-Ion Battery
Authors: Zhang Wenbo , Weber Dominik , Zeier Wolfgang G. , Janek Jürgen
Published: February 2020

Towards the improvement of the state-of-art lithium-ion battery with liquid electrolyte, all-solid-state battery (ASSB) has become one of the most promising systems in the near future, due to the enhancement in the aspect of safety and volumetric energy efficiency. Even though thin film ASSBs have shown excellent performance, it is not suitable for large-scale applications due to its limited size. Therefore, development of bulk ASSB has gained great attentions in recent years. Different inorganic solid electrolytes (SE) have been intensively synthesized and investigated. The electric conductivity was thought to be the limiting factor. But it is no longer a big issue with the constant improvement of conductivity up to 1.2 * 10-2 S/cm.[1] On the other hand, the cell performance is limited to the high interfacial resistance generated between active material and solid electrolyte. A highly resistive layer at the interface between LiCoO2 and sulfide SE was reported.[2] This was considered to be the formation of space-charge layer or the mutual diffusion of elements between oxide cathode material and sulfide SE. [2,3] One of the solutions is the interposition of a buffer layer, which suppressed the increase of interfacial resistance and enabled the high-rate cycle of the ASSB.[4]

However, a detailed study of the ASSB system was not yet reported. In this poster, an ASSB composed of oxide cathode and sulfur based SE will be introduced. The schematic diagram of the cell is shown in Figure 1. The design and the structure of the cell, characterizations of cell components with XRD, SEM and electrochemical impedance will be shown. The relationship between the design of composite cathode and the long cycle stability and rate performance of assembled cells will also be revealed. The influence of interfacial resistance between oxides and sulfide based SE on the cell performance will be discussed. The reasons for the capacity fading observed during cycling will be analyzed and possible solutions will be proposed.

[1]            N. Kamaya, K. Homma, Y. Yamakawa, M. Hirayama, R. Kanno, M. Yonemura, T. Kamiyama, Y. Kato, S. Hama, K. Kawamoto, A. Mitsui, Nat. Mater.
2011, 10, 682.

[2]          N. Ohta, K. Takada, L. Zhang, R. Ma, M. Osada, T. Sasaki, Adv. Mater.
2006, 18, 2226.

[3]          A. Sakuda, A. Hayashi, M. Tatsumisago, Chem. Mater.
2010, 22, 949.

[4]          N. Ohta, K. Takada, I. Sakaguchi, L. Zhang, R. Ma, K. Fukuda, M. Osada, T. Sasaki, Electrochem. commun.
2007, 9, 1486.

Figure 1
High Energy Density Aqueous Electrochemical Capacitors with a KI-KOH Electrolyte
Authors: Wang Xingfeng , Chandrabose Raghu Subash , Chun Sangeun , Zhang Tianqi , Evanko Brian , Jian Zelang , Boettcher Shannon Wachter , Stucky Galen , Ji Xiulei
Published: February 2020

We report a new electrochemical capacitor with an aqueous KI-KOH electrolyte that exhibits a higher specific energy and power than the state-of-the-art nonaqueous electrochemical capacitors.  In addition to electrical double layer capacitance, redox reactions in this device contribute to charge storage at both positive and negative electrodes via a catholyte of IOx
-/I- couple and a redox couple of H2O/Had on the negative electrode, respectively.  Here, we, for the first time, report utilizing IOx
-/I- redox couple for the positive electrode, which pins the positive electrode potential to be 0.4-0.5 V vs. Ag/AgCl.  With the positive electrode potential pinned, we can polarize the cell to 1.6 V without breaking down the aqueous electrolyte so that the negative electrode potential could reach -1.1 V vs. Ag/AgCl in the basic electrolyte, greatly enhancing energy storage.  Both mass spectrometry and Raman spectrometry confirm the formation of IO3
- ions (+5) from I- (-1) after charging.  Based on the total mass of electrodes and electrolyte in a practically relevant cell configuration, the device exhibits a maximum specific energy of 7.1 Wh/kg, operates between -20 to 50 °C, provides a maximum specific power of 6222 W/kg, and has a stable cycling life with 93% retention of the peak specific energy after 14,000 cycles.
Carbon Electrodes for Potassium-Ion Batteries
Authors: Jian Zelang , Luo Wei , Xing Zhenyu , Bommier Clement , Li Zhifei , Ji Xiulei
Published: February 2020

Large-scale stationary energy storage demands technologies based on Earth abundant elements.  The scarcity and rising cost of lithium resources necessitate alternative storage devices to Li-ion batteries.  To date, Na-ion batteries receive most attention; however, the challenge associated to the carbon anodes may potentially affect its commercialization.  Here, we demonstrate that all major bulk carbons, including graphite, soft carbon, and hard carbon, can reversibly store K-ions in non-aqueous electrolytes at room temperature.  All carbon electrodes can exhibit a high reversible capacity near 270 mAh/g.  In particular, ex situ XRD studies on graphite electrodes confirm that KC36, KC24, and KC8 sequentially form upon potassiation, whereas depotassiation recovers graphite through phase transformations in an opposite sequence.  Graphite shows moderate rate capability and relatively fast capacity fading.  In contrast, we discover that both soft carbon and hard carbon exhibit much enhanced rate capability and cyclability compared to graphite.  Cycling of hard carbon is the most stable.  Interestingly, we determined that the hard carbon exhibits an unambiguously better rate capability in K-ion batteries than in Na-ion batteries.  These works may open up a new paradigm toward rechargeable K-ion batteries.
Electrification of Urban Public Transportation Networks
Authors: Patey Timothy John
Published: February 2020

Sustainable mobility includes powering urban public transportation systems with renewable energy. This CO2-neutral vision means replacing diesel bus fleets with all-electric ones. The use of wayside and on-board battery energy storage systems are presented as a way to replace diesel with electric buses, while releasing no particulate matter in the urban surroundings. Through the use of high-power battery design, opportunity charging, and understanding traffic impact, electric bus transportation networks are able to support the life of today’s growing cities.

In this work, the overview and parameterization of an electro-thermal-aging model of a high power Li-ion battery to represent battery use cases in an urban electric bus is presented.  The advantages and shortcomings of battery models are discussed as an engineering tool in dimensioning prototypes.
On Uncertainty Quantification of Thermal Aspects of Lithium-Ion Battery
Authors: Esfahanian Vahid , Dehghandorost Hojat , Chaychizadeh Farzin , Ansari Amir Babak
Published: February 2020

Thermal management of lithium-ion battery pack in hybrid electric vehicles (HEVs) and electric vehicles (EVs) have become a research focus in recent years because performance, safety and life time of battery have significant dependency on temperature distribution throughout the cell. As the first step in designing a reliable thermal strategy, heat generation of battery must be computed accurately. But the most effective physical properties involved in heat source may not be exactly known, possibly because of intrinsic variability which cannot be measured directly in practice.

In any simulation process, some uncertainties appear whose understanding and quantification is critical to assess the differences between the numerical predictions and actual system behavior. For this purpose, these uncertainties must be quantified and propagated through energy equation and heat flux to roll up the uncertainties of interest in order to determine range of temperature distribution, and consequently improve the safety and increase the life-cycle of lithium-ion battery.

Commonly, the uncertain model parameters are represented by random variables/processes which are known as probabilistic techniques. In the present study, stochastic spectral methods based on polynomial chaos (PC) expansions is employed due to their advantages over traditional uncertainty quantification (UQ) techniques, i.e., perturbation-based and Monte Carlo sampling (MCS) methods. In PC-based method, the coefficients of the solution expansion are computed intrusively or non-intrusively. Non-intrusive methods depend on individual realizations to determine the stochastic model response to random inputs and consume less time in comparison with intrusive methods. Since governing equations of lithium-ion battery are very complex, non-intrusive method is chosen in the present study.

Numerical simulation results are verified by discharge process at different C-rates which show good agreement with previous studies. Moreover, PC-based model is implemented to study the effects of parametric model uncertainties on the heat generation of cell and temperature distribution. The obtained numerical results can be used to design more efficient thermal management strategy. Moreover, the numerical results show that the proposed UQ method can accurately compute the variability in the output quantity of interest such as the heat generation and temperature distribution within a wide range of heat convection coefficients for lithium-ion battery.
Charge-Transfer Modified Embedded-Atom Method for LiNi1-x-YCoxMnyO2 Cathode Materials
Authors: Kong Fantai , Longo Roberto C , Liang Chaoping , Yeon Dong-Hee , Park Jin-Hwan , Doo Seok-Gwang , Cho Kyeongjae
Published: February 2020

Benefiting from the high voltage and high capacity, transition metal (TM) layered oxides LiNi1-x-yCoxMnyO2 (NCM) constitute a very attractive family of compounds for the positive electrode of Li-ion batteries. Full quantum simulations such as density functional theory (DFT) method have provided many accurate atomic and electronic structure information, but these understanding is limited to a very small system size of 100-1000 atoms. For micro-scale structures simulations, e.g.
, multiple phases and interfaces in-between, a large-scale simulation method that can simulate 1000-10000 atoms is required. However, high challenges are faced to develop such method for cathode materials, due to the complex TM-O bonding nature with both ionic and covalent components, the diverse interactions in a quinary system, and the continuous charge state variations during delithiation. In this work, we have developed a multi-scale simulation method for NCM cathode materials, based on Charge-Transfer Modified Embedded-Atom Method (CT-MEAM), in which both the long range Coulomb interaction due to charge transfer and the short range non-ionic interaction can be well described. Properties derived from this method match quite well with the corresponding DFT reference work and essential atomic structure behaviors have been modeled, including NCM interfaces, defect structures, size effects, and corresponding TM distribution interactions, etc. The presented simulation method can help facilitate large-scale atomic calculations required for the optimal design of NCM oxides applications.
Measurement of Thermal Behaviour from a Cell Under Operating Loads and Temperatures
Authors: Charles Terrance Priestley
Published: February 2020

This study looks to predict the thermal behaviour of a battery, from cell level upwards, under a variety of operating loads and temperatures in order to improve battery efficiency. Battery charge and discharge behaviour depend on the electrochemical reactions at cell level and these are temperature dependent. A difference between the temperatures in individual cells can alter the performance of an EV, as well as affect the life of a battery pack[TC1] . It is the purpose of this research to understanding how thermal energy is generated at a cell level and how this energy migrates through the cell and into the battery. This understanding will be used to develop predictive assessment of the thermal behaviour of the battery under loading conditions typically experienced within an EV application. This will enable development of targeted interventions that can control the generation and management of thermal energy within the battery leading to a more efficient operation and less battery degradation over the long term.

 [TC1]Examples - % degradation

Life expectancy change?
Multifunctional Silicon Anode for Lithium-ion Batteries
Authors: Bélanger Daniel , Assresahegn Birhanu Desalegn
Published: February 2020

A silicon anode is prepared for application in lithium-ion batteries that can serve different functions such as decreasing the amount of the binder and thus allowing a larger quantity of the active material, better overall integration of the electrode components upon cycling and better stability of the solid-electrolyte interface that could enable to completely get rid of the expensive electrolyte additives. The synthesis of the materials involves the functionalization of a hydrogenated silicon nanopowder by covalent attachment of polyacrylic acid that partially substitutes the silicon-oxygen bond via a silicon-carbon bond. The presence and grafting of polyacrylic acid is confirmed by transmission and scanning microscopy and energy dispersive X-ray spectroscopy, thermogravimetric analysis, Fourier transform infrared and X-ray diffraction spectroscopy. The electrochemical performance of the silicon anode is evaluated by galvanostatic cycling, cyclic voltammetry and four point-probe electronic conductivity measurements. The composite silicon anode showed a significantly improved performance, relative to the hydrogenated Si electrode in terms of gravimetric capacitance (1200 mAh g-1 for more than 100 cycles at 0.5 C rate) with a 100 % capacity retention in a capacity limited discharge/charge cycling. When an unmodified and modified-based electrodes are allowed to fully discharge/charge, a lower initial capacity loss and a better overall physical integrity of the structure is achieved for the latter. Moreover, the composite electrode performs better at high rate discharge/charge cycles. Unlike reports making use of an electrolyte additive for silicon anode, mainly to afford stability of the solid-electrolyte interface and better cyclability, the polyacrylic acid (PAA) modified silicon composite electrode can be cycled without such additive and demonstrate a better electrochemical performance than the unmodified silicon.

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Figure 1