bluuebunny/crossref_metadata_2025 huggingface dataset:
Iron and Titanium Substituted LiCoTixMn1-XO4/ LiCo1-yFeyMnO4: High-Voltage Spinels As Cathode Materials for Li-Ion Batteries
Authors: Dräger Christoph , Indris Sylvio , Ehrenberg Helmut
Published: February 2020

Mn-based spinel materials are highly promising high-voltage cathode materials for Li-Ion batteries due to their structural peculiarity, resulting in their high rate capability and excellent room temperature cycling stability. The energy density of these Mn spinel based materials can be further increased by substituting Mn with electrochemically active 3d transition metals like nickel, iron or cobalt, so that the operating potential of the cathode is further increased1,2. This substitution is also reducing the Mn3+ content in the spinel and should therefore stabilize the cathode-material during cycling. In the present work, the high-voltage spinel LiCoMnO4 and its titanium or iron substituted derivatives LiCoTixMn1-xO4 (0.02 ≤ x ≤ 0.16) / LiCo1-yFeyMnO4 (0.05 ≤ y ≤ 0.2) are in the spotlight.

To investigate these compounds, our research is focused on the synthesis, structural and electrochemical characterization as well as spectroscopic methods in order to compare their properties and capabilities. Therefore, several techniques such as thermogravimetry in different states-of-charge (SOC), NMR spectroscopy in different SOC, and in situ powder synchrotron diffraction during electrochemical cycling and also during heating are applied.

Galvanostatic cycling reveals that about 70% of the lithium can be extracted and reinserted electrochemically in the voltage window from 3.5 to 5.3 V against Li from/into LiCoMnO4, LiCoTi0.06Mn0.94O4 or LiCo0.90Fe0.10MnO4 (Fig. 1). In situ synchrotron powder diffraction results show that Li extraction/insertion occurs via a single-phase mechanism over the whole range of Li contents and over the whole voltage-range for Ti substituted and unsubstituted LiCoMnO4 spinels (Fig. 2).

Financial support from the Federal Ministry of Education and Research (BMBF) within the DESIREE project, grant no. 03SF0477B, is gratefully acknowledged.

(1)      Alcántara, R.; Jaraba, M.; Lavela, P.; Tirado, J. L. Chem. Mater.
2003, 15 (5), 1210–1216.

(2)      Bhaskar, A.; Mikhailova, D.; Kiziltas-Yavuz, N.; Nikolowski, K.; Oswald, S.; Bramnik, N. N.; Ehrenberg, H. Prog. Solid State Chem.
2014, 42 (4), 128–148.

Figure 1
All-Solid State Rechargeable Batteries: Manufacturing of Composite Cathodes
Authors: Peters Fabian , Andre Felix , Schwenzel Julian
Published: February 2020

All-solid-state batteries have great potential for both improvement of cell safety and increase of energy density. Safety improvements are obviously attained by removing the flammable liquid electrolyte. For the energy density, values up to 400Wh/kg are often claimed. Results of theoretical calculations reveal that specific energies beyond 400 Wh/kg and energy densities of more than 1200 Wh/L can be reached with all solid state Li-ion cells.

Great challenges remain in manufacturing of the components and the cell stack. All-solid battery cells as presented here typically consist of a lithium metal anode, a thin all-solid separator and a composite cathode. While the Lithium metal anode and the separator can probably be single-phase, the composite cathode requires a much more complex structure to ensure both good electrical and ionic conductivity. In addition, the contact resistance at the components’ interfaces needs to be minimized. Such cathodes ideally consist of evenly dispersed particles in solid electrolyte, with no remaining porosity.

In this work, a practical approach for manufacturing of all-solid composite cathodes is presented. The impact of different compositions and manufacturing technologies on the electrode structure and conductivity is shown. Composite cathodes comprising active material, polymer based electrolytes and conductive agents are manufactured by dry mixing, hot pressing and extrusion, respectively. SEM and TGA-DSC analysis reveal the structure of the resulting electrodes. Results of density and porosity measurements are also shown. Ionic and electrical conductivities are measured as well.

In conclusion, the impact of composition and processing on the quality of all-solid state composite cathodes is shown and discussed in this work. Recommendations towards improved manufacturing routes are derived.

Figure 1
Study of Crosslinked Solid Polymer Electrolyte for All-Solid-State Lithium Battery
Authors: Liu Jin , Lin Yue , Li Jie , Liu Yexiang , Liu Kathy , Wang Xuming
Published: February 2020

Developing all-solid-state lithium batteries has been one of the most effective methods to ensure safety for new energy devices, especially with flexible solid polymer electrolyte as a crucial component. However, the electrolyte exhibits low ionic conductivity at room temperature that obviously inhibits the progress of all-solid-state lithium batteries. In this study, we develop a few solid polymer electrolytes to enhance the lithium ion transport ability by using crosslinking polymer methods. The results show that adjustments of the cross-linked centers and branches of the polymer significantly improve the ionic conductivity of the electrolyte. Besides, all-solid-state lithium sulfur batteries with the solid electrolytes are studied. The morphology and structures at the electrode/electrolyte interfaces during the charge and discharge processes are investigated by FIB-SEM, EIS, FTIR and NMR. The effects of molecular structures of solid polymer electrolytes on ionic conductivity and interfacial compatibility are discussed.
Garnet Based Electrolytes Based on Li6.75La3-XMXZr1.75Ta0.25O12-D for All Solid State Lithium Batteries: Systematic Doping on the Lanthanum Site with Two and Three-Valent Cations
Authors: Struzik Michal , Genta Jessica , Pfenninger Reto , Garbayo Inigo , Rupp Jennifer L. M.
Published: February 2020

Lithium stuffed garnet oxides such as Li7La3Zr2O12 have attracted considerable attention as promising candidate for solid electrolytes for All Solid State Lithium Ion Batteries. Their high Li-ion conductivity of ca. 1x10-3 Scm-1, wide temperature stability window, stability against metallic lithium and compatibility with high voltage new electrode materials implies new perspectives for large-scale applications for elevated temperatures as well new cell designs for thin film chip-integrated micro-batteries. The key to a successful application of Li-garnets is to ensure high Li-ion conductivity and electrochemical stability with other battery components.

Despite the great interest on this class of materials, there is still uncertainty on the role of La- and Zr-sites co-doping on the structural stability and phase as a function of ionic radii of the dopant and Li-transport properties. Here we present extensive study on structural properties and ionic transport of the Li6.75La3-xMxZr1.75Ta0.25O12 system, where M=Er3+, Y3+, Nd3+, Gd3+, Sr2+, Ba2+, Ca2+. Utilizing X-Ray diffraction, Raman spectroscopy and electron microscopy we discuss crystal structure properties and stability of the materials with respect to the ionic transport properties analysed by impedance spectroscopy in wide temperature window for future electrolyte applications in all solid state batteries.
NMR Studies of Ion Transport in Ultra-Concentrated Aqueous Lithium Electrolytes
Authors: Peng Jing , Xu Kang , Wang Chunsheng , Suo Liumin , Gobet Mallory , Munoz Stephen , Greenbaum Steven
Published: February 2020

The electrolytes currently used in lithium ion batteries are a source of many cost and safety issues, which can be mitigated by a switch to aqueous electrolyte.  This was, until recently, precluded by the narrow electrochemical stability window of the aqueous electrolyte, a problem which severely limited the practical voltage and energy density of the battery.  However, recent developments have shown that it is possible to open up this stability window by increasing concentration of the salt (LiTFSI), enabling the formation of an interphase.  This opens the door for a fresh focus on the properties of aqueous electrolytes. (1)

Nuclear Magnetic Resonance (NMR) is a powerful tool for exploring ionic and molecular transport in electrolytes.  The nuclei in question (7Li , 19F, and1H) are particularly well-suited to measurement by NMR, due to their gyromagnetic ratios and abundances.

We performed NMR measurements on a range of concentrations of LiTFSI aqueous electrolyte, varying from 1 m to 21 m.  In particular, pulsed gradient spin-echo self-diffusion experiments were performed on a 300 MHz spectrometer.  Self-diffusion coefficients for both ions and water molecules were obtained over a range of temperatures from 20°C to -60°C. The diffusion results are displayed in Figs. 1 and 2.  As expected, we note a general trend of smaller diffusion coefficients with lower temperature, as well as smaller diffusion coefficients with higher salt concentration.  Cation transference numbers were determined directly from the diffusion measurements and those results are listed in Table 1. The cation transference number increases as the temperature falls and the salt concentration rises, as well. Although this investigation focuses on the transport properties of the liquid phase, ongoing work will address SEI formation on a variety of anodes in contact with this unusual aqueous system.

References

1. Liumin Suo et al.  "Water-in-salt" electrolyte enables high-voltage aqueous lithium-ion chemistries. Science.
350, 938 (2015).

Figure 1
Structural and Compositional Studies of Initial SEI Formation Employing Surface Sensitive Techniques
Authors: Renner Frank Uwe , Moeremans Boaz , Cheng Hsiu-Wei , Valtiner Markus
Published: February 2020

Electrolyte decomposition and the formation of the solid-electrolyte interface SEI depends critically on the used active materials, electrolytes or electrolyte additives. A better knowledge of the initial steps of SEI formation is thus necessary to cope with new active anode materials or new electrolytes. The initial wetting as well as the further SEI growth are critical for the stability of the applied battery system. Here we present the use of different surface sensitive techniques to address the SEI formation. Next to Synchrotron-based high-energy or hard x-ray XPS (HAXPES) or AFM we belief that studies employing a surface force apparatus (SFA) may play a more prominent role in the future. We report first results on using an electrochemical SFA setup which was modified for addressing battery interfaces. The SFA technique detects changes in layer thickness together with the mechanical behavior of the growing surface films. The potential-induced SEI formation was followed first on Au, but also the initial wetting behavior of a EC/DEC electrolyte on model electrodes such as mica, gold or graphene was studied providing an unprecedented insight in ultrathin wetting layer formation under confined conditions.
Graphite-Si Based Cell Performance in Alternative Electrolytes
Authors: Dzwiniel Trevor L , Pupek Krzysztof Z. , Krumdick Gregory , Abraham Daniel P
Published: February 2020

In the quest to increase energy density of lithium-ion cells, graphite-silicon composite electrodes have been extensively investigated. The long-term performance of these electrodes is limited due to the instability of the electrode-electrolyte interface that is continually disrupted during the charge-discharge cycles. In order to improve the performance of silicon-based negative electrodes, researchers have developed various strategies that include novel electrolyte formulations among many others.

We conducted a comparative study of several electrolyte formulations based on LiFSI, LiTFSI, LiPF6, and mixtures thereof  in fluorinated carbonates like methyl 3,3,3-trifluoroethyl carbonate, bis(3,3,3-trifluoroethyl) carbonate, 3,3,3-trifluoropropylene carbonate, and monofluoropropylene carbonate.

Comprehensive data from rate study, impedance and cycle life evaluation in NCM523//Gr-Si CR2032 full cells will be presented and discussed.
Development of Novel Electrolyte Additives for Designed Surface Modification
Authors: Lucht Brett L
Published: February 2020

An investigation of the effect of electrolyte on performance of in lithium ion batteries will be presented  The electrochemical performance of common electrolyte formulations will be discussed along with detailed ex-situ surface analysis of the cycled electrodes.  The ex-situ analysis allows the development of an understanding of the role of the electrolyte and common additives in the structure of interfacial electrode films on both the anode (solid electrolyte interphase, SEI) and on the cathode.  Correlation of the structure of the surface films with the performance limiting reactions in lithium ion batteries affords insight into the mechanism of interfacial film formation and function. The mechanistic insight is used to systematically develop novel additives designed for specific electrode surface modification to afford optimized electrochemical performance.  The electrochemical performance and ex-situ surface analysis of electrodes cycled with novel Additives for Designed Surface Modification (ADSM) will be presented.
Investigation on Electrochemical Behavior of Rhombohedral Lithium and Sodium Vanadium Phosphate Cathode for Ion Storage System
Authors: Yang Junghoon , Kim Soo Young , Kang Yong-Mook
Published: February 2020

Sodium ion batteries have attracted extensive interest based on its low cost and its similarity to lithium ion batteries. However, unlike what would be assumed that sodium storage mechanism is similar as lithium, recent reports show that sodium storage mechanisms in most materials could be significantly different from the corresponding lithium counterpart materials. These are mainly come from unexpected and unpredictable structure differences caused by different ionic radius between lithium ion and sodium ion. Recently, researchers are interested in the structural differences and their electrochemical behavior of lithium containing materials and sodium counterparts.

Li3V2(PO4)3 ­(LVP) and Na3V2(PO4)3 (NVP) are promising cathode materials for both lithium and sodium ion batteries, respectively. However, they have different structure when they are prepared by synthetic process. LVP prefers monoclinic structure but NVP formed rhombohedral structure and this difference caused different electrochemical behavior for lithium ion and sodium ion. The most distinguishing difference of the materials is available number of ions that participate in electrochemical reaction. Monoclinic LVP utilize whole lithium ions, thus LVP exhibits high theoretical capacity of 197 mAh/g. However, rhombohedral NVP only can use two sodium ions in the structure that limits it theoretical capacity of 118 mAh/g. The limitation mainly contributed to different crystallographic position of sodium ions in the structure that caused different migration energy. Thus, we need to approach to the problem with structural view point to overcome the electrochemical limitation of NVP.

To deduce the electrochemical behavior limitation of NVP with structural viewpoint, we prepared LVP materials with rhombohedral structure to observe the differences between the samples. The materials which have similar rhombohedral type structure LVP could be prepared from rhombohedral NVP by ion exchange method. From the rhombohedral LVP, we observed that more than two lithium ions can be extracted from the structure and new voltage plateau at high voltage which are not observed in NVP case. In this study, we will suggest different electrochemical behavior of LVP and NVP cathode materials based on different cation type and detailed structural studies during electrochemical reaction which will give the clues for understanding the different electrochemical behavior. The derived structural difference would also give new insights for modifying the structural features of NVP to enhance the electrochemical performances.
Superior Sodium-Ion Storage Performance of Co3O4@Nitrogen-Doped Carbon: Derived from a Metal-Organic Framework
Authors: Wang Yijing , Huang Zhenguo , Wang Ying
Published: February 2020

Nitrogen-doped carbon coated Co3O4
nanoparticles (Co3O4@NC) with high Na-ion storage capacity and unprecedented long-life cycling stability are reported in this paper. The Co3O4@NC was derived from a metal-organic framework ZIF-67, where the Co ions and organic linkers were respectively converted to Co3O4 nanoparticle cores and nitrogen-doped carbon shells through a controlled two-step annealing process. When applied as an anode for the sodium ion battery (SIB), Co3O4@NC delivers a high reversible capacity of 506, 317, and 263 mAh·g−1 at 100, 400, and 1000 mA·g−1, respectively. A capacity degradation of 0.03 % per cycle over 1100 cycles was achieved at a high current density of 1000 mAh·g−1. The outstanding Na-ion storage performance can be ascribed to the nitrogen-doped carbon coating (NC), which facilitates the capacitive reaction, minimizes the volume changes of Co3O4, and also enhances the electronic conductivity. This work sheds light on how to develop high-performance metal oxide@NC nanocomposites for SIBs.
High Performance Sodium-Ion Batteries Based on Prussian White Electrode
Authors: Lu Yuhao , Vail Sean , Zhao Xin , Song Jie , Pan Wei , Lee JJ
Published: February 2020

Sodium-ion batteries (NIB) consisting of a Prussian White (PW) cathode, a hard carbon anode and an organic electrolyte were prepared using conventional Li-ion battery (LIB) fabrication protocol. The  Na2MnFe(CN)6 (Prussian White) was synthesized via a co-precipitation approach, which contains a Mn (III)/(II) redox couple and two Na ions in each unit cell. Attributed to the high Na concentration, fast ion transfer kinetics and mechanical robustness, the Prussian White cathode demonstrated a high capacity beyond 160 mAh/g, along with superior rate capability and cycling stability. The excellent performance and economical production method makes the NIB a promising alternative to lithium-ion batteries (LIB) in many application fields.

Figure 1
MSn2 (M= Mn, Fe, Co) Intermetallics As Anode Materials for Na-Ion Batteries
Authors: Vogt Leonie O , Marino Cyril , Villevieille Claire
Published: February 2020

Tin is a promising anode material for the storage of large amounts of lithium and sodium; it currently boasts one of the highest specific charges: 990 mAh/g and 846 mAh/g in lithium-ion and sodium-ion batteries upon conversion to Li4.4Sn and Na3.75Sn, respectively1. However, storing such large quantities of these ions is typically accompanied by large volume expansions of up to 400%, which leads to particle fracture and thus electrical isolation resulting in rapid capacity fade with cycle number. By alloying an active metal with an inactive metal the reaction mechanism can be modified, allowing substantial specific charge to be achieved while mitigating the detrimental effects of the volume expansion.

Here, we alloy Sn with inactive transition metals Mn25, Fe26 and Co27 to form the tetragonal intermetallic MSn2 (I4/mcm). Since none of the three transition metals form alloys with Na on their own, they are expected to be inactive in the storage of Na; however the three MSn2 materials (M = Mn, Fe, Co) do not behave identically during cycling in sodium ion batteries, demonstrating that the transition metal in fact plays an “active role” in such systems. With the three materials being isostructural and the transition metals being adjacent to each other in the periodic table, the precise influence of the electronic structure of the supposedly inactive transition metal on the active system (here Sn) could be identified.

Using electrochemical measurements (CV, GITT, galvanostatic cycling and rate capability), ex situ and operando X-ray powder diffraction (XRD) data and X-ray absorption spectroscopy (XAS) we elucidate the reaction mechanism of all three materials and uncover that the reaction between Na and MSn2 (M = Mn, Fe, Co) is facilitated by intermediate state formation, dependent on the transition metal. The results of this study give an insight into designing the most effective combinations of active and inactive metals that may be selected as suitable alloy hosts for the next generation of novel battery materials.

References:

(1)           Komaba, S.; Matsuura, Y.; Ishikawa, T.; Yabuuchi, N.; Murata, W.; Kuze, S. Electrochemistry   Communications
2012, 21, 65.

Acknowledgment:

The Swiss National Science Foundation is thanked for financial support (Project 200021_156597). This work was performed within the Swiss Competence Center of Energy Research Heat and Storage (SCCER) framework.

Figure 1
Organic Pigment Electrode in Aqueous Magnesium Ion Batteries
Authors: Rodríguez Pérez Ismael Antonio , Wang Xingfeng , Ji Xiulei
Published: February 2020

Lithium-ion batteries (LIBs) have made tremendous successes in powering electronics and electric vehicles.  Yet, LIBs face an insurmountable challenge in sustainability for large-scale stationary applications. Lithium, without effective recycling strategies, is too rare to be used at the current pace, rendering a concern over this great technology.  Efforts are, therefore, guaranteed to pursue inexpensive and sustainable energy storage solutions.  As of today, Na-ion batteries have received tremendous attention; however, it faces its own hurdle before commercialization, which originated from the choice of anodes.  Alike sodium and potassium, magnesium is a benign and extremely Earth abundant element.  So far, most electrodes for Mg2+ ion storage have been studied in non-aqueous electrolytes, where intrinsic properties of Mg2+ ion storage might be covered up by factors, including instability of the electrolyte and large overpotentials of Mg metal counter/reference electrode.  To date, Mg2+ ion electrodes are still limited to Chevrel compounds or metal oxides.  Here, we, for the first time, report reversible Mg2+ ion storage properties in 3,4,9,10-perylenetetracaboxilicdianhydride (PTCDA) in an aqueous electrolyte.  In the potential range of -0.6 to 0.2 V vs Ag/AgCl reference electrode, PTCDA is able to deliver a reversible specific capacity of 125 mAh g-1, a good rate capability with 75 mAh g-1 at 500 mA g-1 and a reasonable cycling stability for 100 cycles.  This work opens up a new avenue to harvest high-density charge storage for Mg2+ ions in an aqueous medium, which presents a large potential in magnesium ion batteries.
Operando μ-Beam Diffraction Following the Decomposition of Individual Li2O2 Grains in a Non-Aqueous Li-O2 Battery
Authors: Ganapathy Swapna , Anastasaki Mariastella , Heringa Jouke R , van Hulzen Martijn , Adams Brian , Wright Jonathan P. , Nazar Linda F , van Dijk Niels H. , Wagemaker Marnix
Published: February 2020

Fundamental research into the Li-O2 battery system has gone into high gear, gaining momentum due its very high theoretical specific energy. The electrochemical processes that drive this battery are represented by the total chemical reaction:. We report for the first time the technique of operando micro beam X-ray diffraction applied to monitor the decomposition of individual grains of Li2O2 in a working non-aqueous Li-O2 battery. Due to the extremely small beam size and bright X-rays, the diffraction rings break up into spots, each spot representing a grain of Li2O2 having nanometer dimensions. We have studied two kinds of Li2O2; the first, electrochemically generated toroids of Li2O2 comprising of Li2O2 platelets formed at a low discharge current density of (E-Li2O2) and the second, chemically prepared Li2O2 incorporated into a carbon electrode (C-Li­2O2). The most obvious difference the two is the shape and size of the primary crystallites. Using this technique, we have time-resolved information on the individual transformation of a number of grains of both E-Li2O2 and C-Li2O2, following their complete decomposition.

Figure 1 Voltage curve corresponding to the Oxygen Evolution Reaction (OER) using a current density of 100 mA/cm2, and the corresponding evolution of a 2D (100) reflection of Li2O2 following its decomposition.

Figure 1
Dual Electrolytes Rechargeable Li-Air and Li-Water Batteries
Authors: Kwon Nam Hee , Sheima Yauhen , Fromm Katharina M
Published: February 2020

Lithium is the lightest metal with the most negative potential (-3 V vs. SHE). Combining oxygen and water as a cathode and an electrolyte with lithium, rechargeable Li-air and Li-water batteries provide higher energy densities than the conventional Li-ion batteries.

However, the redox reversible reactions and cyclability of those batteries are far below expectations. Among the several structures of Li-air batteries, using an aqueous electrolyte provides a higher efficiency and cyclability due to the high ionic mobility and the solubility of discharge products [1]. However, water must not contact lithium metal anode to avoid violent reaction, producing heat and gas evolution. Thus, we apply organic electrolyte on lithium metal anode and aqueous electrolyte on cathode to protect lithium metal and to make  highly reversible electrochemical reactions, respectively.

During discharging, the value of pH increases due to the formation of LiOH, damaging the membranes [2,3] and the saturation of LiOH formation [4].

In the system of Li-air, the solubility of O2 in aqueous solution is a key parameter to obtain the highly reversible electrochemical reactions and high energy density.

We studied the O2 solubility in terms of the concentration of LiOH aqueous solution and other salts mixed solutions by means of the electrochemical techniques. Fig. 1 shows the O2 solubility increased with decreasing the concentration of LiOH. We will show the behavior of the O2 solubility of different salts mixed aqueous solutions and the charge/discharge behaviors in dual electrolytes systems.

Fig. 1. The concentrations of O2 in terms of the various concentrations of LiOH aqueous electrolyte.

References

[1] X. Wang, Y. Hou, Y. Zhu, Y. Wu, R. Holze, Scientific Reports 2013, 3, 1401.

[2] D.-J. Lee, O. Yamamoto, D.-M. Im, Y. Takeda, N. Imanishi, 2012, Patent Application No. 13/191769.

[3] J. Christensen, P. Albertus, R. S. Sanchez-Carrera, T. Lohmann, B. Kozinsky, R. Liedtke, J. Ahmed, A. Kojic, J. Electrochem. Soc. 2012, 159, R1-R30.

[4] Y. Wang, H. Zhou, J. Power Sources 2010, 195, 358-361.

Figure 1
Investigating Olivine Cathode for Rechargeable Magnesium Battery with Theoretical and Experiment Approach
Authors: Zhang Ruigang , Mizuno Fuminori , Ling Chen
Published: February 2020

Lithium ion batteries (LIBs) are quickly becoming the mainstream power sources for environmentally friendly vehicles such as hybrid vehicles (HV), plug-in hybrid vehicles (PHV) and electric vehicles (EV) due to their high energy density. On the other hand, a battery system with even higher energy density is required for the long-range PHV and EV applications, and therefore, post lithium ion batteries (PLIB) such as Li-sulfur batteries and Li-air batteries have been getting more attention in recent years. Rechargeable magnesium batteries are also a candidate for the PLIB thank to the natural abundance of magnesium and the absence of dendrite formation when magnesium metal is used as the anode. In addition, the magnesium batteries are expected to have high energy density because of its divalent nature. However, there is not much progress on the development of novel cathodes since an innovation of Chevrel phase materials such as MgxMo6S8. The difficulty lies in the strong polarization character of the small and divalent Mg2+ and consequently the intercalation and diffusion of Mg2+ ions is somewhat difficult and complicated.

Because of the so-called “diagonal relationship” in the periodic table stating the chemical similarity between lithium and magnesium, significant amount of efforts have been attempted to use compounds analogous to classical Li-ion battery cathode as Mg-intercalation hosts. As olivine LiFePO4 is one of the commercialized Li-ion battery cathode, it is of great interest to examine the performance of olivine compounds as Mg battery cathode. In this work, a comprehensive study about the performance of olivine FePO4 as Mg battery cathode is performed. With a combined theoretical and experimental approach we show that the intercalation of magnesium does not occur in the electrochemical operations. On the contrary to the common belief that the intercalation of magnesium is critically determined by the mobility of Mg2+ ions in the lattice, we demonstrate that the failure of FePO4 cathode is due to the formation of amorphous layer in the electrochemical process that passivates the active particle, similar to the phenomenon that we reported before for α-MnO2 cathode. Our research provides new insight for the magnesiation mechanism of a classical cathode and elucidate several directions towards future rechargeable Mg battery.
Understanding the Good Kinetics of Mo6S8 As Cathode in Mg Ion Batteries By Key Electronic States
Authors: Yu Pengfei , Han Fudong , Feng Xuefei , Long Xinghui , Liu Xiaosong , Wang Chunsheng , Liu Zhi
Published: February 2020

Mg rechargeable batteries are being considered as one of the most prospective alternatives for Li rechargeable batteries because of their merits including Mg abundance, absence of Mg dendrite and high theoretical specific capacity attributed to two-electron charge transfer reaction process. [1] However，the achievable performance of Mg rechargeable batteries is still limited regarding their practical application. The key limitation to this lies in cathode. To date, Chevrel phase Mo6(SxSe1-x)8 is the only cathode material in which Mg2+ can be efficiently intercalated/deintercalated. Extensive theoretical and experimental studies have been done to screen out promising cathode materials by constructing the crystal structure similar to Chevrel phase. However, successful research has been rarely reported. It indicates that only taking into account of the crystal structure is not sufficient enough to explore the Mg storage/transport behavior in the electrode. Given the facts that the two-electron charge transfer process was involved in Mg batteries while the great success has been made in the studies on lithium ion batteries through the key electronic states [2-5], the evolution of electronic structure in Chevrel phase might provide more important information to elucidate the physical nature of Mg storage/transport in the electrode. However, the experimental study on the evolution of electronic structure in Chevrel phase cathode is rare. In this report, the study on the unoccupied states of a typical Chevrel phase Mo6S8 including Mo L-edge and S K-edge were conducted by tender X-ray absorption spectroscopy. In contrast with the conventional understanding that only Mo cation is involved in the charge transfer process, the key electronic states at the pre-edge of S spectra were also found to be evolved regularly with different states of charge/discharge. It is assigned to the hybridization between Mo 4d states and S 3p states. The evolution of this state opens a gate to reveal the nature of good kinetics in Chevrel phase.

1. Aurbach, D., et al., Prototype systems for rechargeable magnesium batteries. Nature, 2000. 407(6805):

p.724-727.

2. Liu, G., et al., Polymers with Tailored Electronic Structure for High Capacity Lithium Battery Electrodes.

Advanced Materials, 2011. 23(40): p. 4679-4683.

3. Liu, X., et al., Phase Transformation and Lithiation Effect on Electronic Structure of LixFePO4: An In-Depth

Study by Soft X-ray and Simulations. Journal of the American Chemical Society, 2012. 134(33): p. 13708-13715.

4. Yang, W., et al., Key electronic states in lithium battery materials probed by soft X-ray spectroscopy. Journal of

Electron Spectroscopy and Related Phenomena, 2013. 190, Part A(0): p. 64-74.

5. Liu, X., W. Yang, and Z. Liu, Recent Progress on Synchrotron-Based In Situ Soft X-ray Spectroscopy for Energy

Materials. Advanced Materials, 2014: 7710-7729.
Kinetics of Alloying and Deposition in Multivalent Battery Anodes Using Real-Time X-Ray Diffraction
Authors: Fister Timothy T , Han Sang-Don , Kim Soojeong , Vaughey John T. , Hubaud Aude A. , Fenter Paul , Esbenshade Jennifer , Lundberg Kimberly E. , Gewirth Andrew A
Published: February 2020

A multivalent successor to lithium ion batteries will likely incorporate a metal anode. However, many electrodeposition processes are prone to energy losses from side reactions and overpotentials for plating or stripping. To develop a link between the kinetics of crystal growth/dissolution with electrochemical data, we have followed electrodeposition of Mg and Zn with operando x-ray diffraction using a variety of electrolytes and current collectors. In some cases we find that alloying or passivation competes with metal deposition and can dramatically alter the morphology of the deposited metal, as seen by texture analysis of the diffraction.
Identifying Solution Based Catalysts for the Lithium-Oxygen Battery
Authors: Richardson William , Garcia-Araez Nuria
Published: February 2020

Increasing demand for lighter and more powerful batteries has driven research into alternative technologies. One system that has received significant attention is Lithium-Oxygen. This system exploits the reduction of oxygen to lithium peroxide, by lithium metal, to provide a theoretical specific energy of 3500 Wh kg-1. One of the major problems facing the Lithium-Oxygen battery is the passivation of the air electrode caused by insoluble lithium oxides and lithium carbonate formed during cycling. These products are not completely oxidized during the charge  step and therefore accumulate within the electrode causing the capacity to fade with each cycle1.

This work focuses on identifying solution based catalysts in non-aqueous electrolytes to facilitate the oxidation of these insoluble products2. The catalysts are oxidized at a higher potential than the lithium peroxide but undergo much faster electron transfer. Once oxidized the catalyst is able to oxidize any lithium peroxide or lithium carbonate remaining on the surface, unblocking the pores and therefore preserving the capacity over subsequent cycles. Analysis of the carbon electrode by x-ray diffraction is able to confirm Li2O2 as the discharge product. While the evolution and consumption of oxygen during cycling has been studied using on-line mass spectrometry. The figure included displays cyclic voltammograms of oxygen reduction and evolution with (black) and without (red) a catalyst. This demonstrates that that incorporation of such a catalyst can significantly reduce electrode passivation and therefore dramatically improve the cycle life of the cell. 

[1] Garcia-Araez, N.; Novák, P. Critical Aspects in the Development of Lithium–air Batteries. J. Solid State 
Electrochem.
2013, 17, 1793–1807.

[2] Lacey, M. J.; Frith, J. T.; Owen, J. R. A Redox Shuttle to Facilitate Oxygen Reduction in the Lithium Air Battery. Electrochem. commun.
2013, 26, 74–76.

Fig. 1. Cyclic voltammogram of oxygen reduction and evolution at 50mV s-1. Cell consisted of a two electrodes; a glassy carbon working electrode (3mm) and Lithium foil counter/ reference electrode.

Figure 1
Novel Electrolytes for Metal-Air Batteries
Authors: von Czarnecki Peter , Ahrens Maria , Rösler Sina , Schubert Thomas J. S.
Published: February 2020

Ionic liquids (ILs) – salts that are liquid at temperatures below 100°C – show interesting profiles of physical and chemical properties which allows their use as safe electrolytes[1,2,3] in batteries. These properties include tunable viscosities and conductivities, chemical and thermal stability as well as large electrochemical windows, and incombustibility at temperatures below their decomposition point.

Fig. 1: Temperature-dependent influence of additive X on the viscosity of IL-mixtures

In this presentation we will report our latest developments in the field ionic liquid based electrolytes for different types of metal-air batteries. The focus will be the use of mixtures of ionic liquids as well as of mixtures of ionic liquids and solvents in order to increase performance and safety of metal-air batteries.

References:

[1]        M. A. Taige, D. Hilbert, T. J. S. Schubert Z. Phys. Chem.
2012, 226, 129.

[2]        M. Armand, F. Endres, D. R. MacFarlane, H. Ohno, B. Scrosati Nature

         
Materials
2009, 8, 621.

[3]        D. Gelman, B. Shvartsev, Y. Ein-Eli
J. Mater. Chem. A

, 2014,
2
, 20237.

Figure 1
Thiol-Based Electrolyte Additives for High-Performance Lithium-Sulfur Batteries
Authors: Wu Heng-Liang , Shin Minjeong , Liu Yao-Min , See Kimberly A , Gewirth Andrew A
Published: February 2020

Here, we propose thiol-based electrolyte additives (biphenyl-4,4’-dithiol (BPD)) to enhance the capacity retention of lithium-sulfur batteries. In-situ Raman and UV-Vis spectroscopy are used to investigate the effect of the additive on the sulfur reduction mechanism. Raman spectroscopy shows that long chain polysulfides (S8
2-) are formed via S8 ring opening in the first reduction process at ~2.4 V vs Li/Li+ and short chain polysulfides such as S4
2-, S4
-, S3
․
- and S2O4
2- are observed with continued discharge at ~2.0 V vs Li/Li+ in the second reduction process. In the Kinetic study, rate constants obtained for the appearance and disappearance polysulfide species show that short chain polysulfides are directly formed from S8 decomposition. The polysulfide oxidation and reduction is quasi-reversible. With the BPD additive, an additional reduction process is observed at ~2.1 V vs Li/Li+. This reduction is associated with the formation of BPD-polysulfide complexes. The BPD-polysulfide complexes form at ~2.1 V followed by the formation of short chain polysulfides upon further discharge. The reduction of these complexes is reversible during the charge process. The BPD additive inhibits the formation rate of short chain polysulfides, suggesting that there is a strong interaction between BPD and short chain polysulfides. In-situ UV-Vis spectroscopy shows that the polysulfide solubility decreases in the presence of the BPD additive and forms thiol-polysulfide complexes during the cycling. The (-)ESI-MS shows the formation of BPD-S and BPD-S2 and BPD-S3, suggesting that BPD interacts with short chain polysulfides. The decomposition of the thiol-based additive was found during the battery cycling and resulted in a dense and smooth SEI film on the Li anode.

References:

(1) Zhang, S.S. et al J. Power Sources 2013, 231, 153-162.

(2) Barchasz, C.  et al., Anal. Chem. 2012, 84, 3973.

(3) Cuisinier, M. et al., J. Phys. Chem. Lett. 2013, 4, 3227.

(4) Hagen, M. et al., J. Electrochem. Soc. 2013, 160, A1205.
Self-Assembled MWCNT Interlayer for High-Performance Lithium-Sulfur Batteries
Authors: Kim Hee Min , Manthiram Arumugam , Sun Yang-Kook
Published: February 2020

Rechargeable batteries are one of the prime approaches for electrical energy storage. The current lithium-ion battery technology based on transition-metal oxide cathodes and graphite anode have limited energy storage capacity, so there is immense interest to develop alternate high-capacity cathode and anode materials. Lithium-sulfur (Li-S) batteries are appealing in this regard as they offer a high energy density of 2500 Wh kg-1 when coupled with lithium-metal anode due to the large charge-storage capacity of sulfur.[1]
Moreover, sulfur is much more abundant, inexpensive, and non-toxic compared to the transition-metal oxide cathodes.

There are several challenges with the Li-S batteries, such as low electrical conductivity of sulfur and the discharge product Li2S and the migration of dissolved polysulfides from the cathode to the anode, resulting in low efficiency and inadequate cycle life.[2] Well-designed carbon-sulfur composites have been extensively explored to overcome these issues.[3] In these strategies, sulfur was entrapped in carbon structures using porous carbon, carbon nanotubes (CNT), and hollow carbon spheres. Carbon backbone serves as the electron conducting path for sulfur and reduce polysulfide migration by trapping the polysulfides during cycling. However, polysulfide migration still occurs and cycle life is inadequate for practical applications. Manthiram group and other groups introduced the use of carbon-paper interlayers in between the sulfur cathode and the polymer separator or carbon-coated membrane and demonstrated high sulfur utilization with better cycle life due to the suppression of polysulfide diffusion to the anode and the serving of the carbon-paper interlayer as a pseudo-upper current collector.[4]

We present here the fabrication of an interlayer consisting of MWCNT and the electrolyte in a single fabrication process. Such MWCNT-electrolyte-paper interlayers are much more effective compared to the bare MWCNT-paper interlayer due to the fast ionic and electronic transport and a better interface between the sulfur cathode and the interlayer as well as between the separator and the interlayer.

References

[1]. B. Scrosati, J. Hassoun, Y.-K. Sun, Energy Environ. Sci. 2011, 4, 3287.

[2]. Y.-X. Yin, S. Xin, Y.-G. Guo, L.-J. Wan, Angew. Chem. Int. Ed. 2013, 52, 13186-13200

[3]. A. Rosenman, E. Markevich, G. Salitra, D. Aurbach, A. Garsuch, F.F. Chesneau, Pan, Adv. Energy Mater. 2014,1500212.

[4]. Y.-S. Su, A. Manthiram, Chem Comm. 2012, 48, 8817-8819.
Electrochemical Properties of Mo Doped High Voltage Cathode for Lithium-Ion Battery
Authors: Kazda Tomáš , Vondrák Jiří , Vanýsek Petr , Sedlaříková Marie , Tichý Jiří , Čudek Pavel
Published: February 2020

Lithium-ion batteries play an important role in portable electronic devices and e-mobility due to their high gravimetric energy density. However they are not able to meet the growing demand for higher capacity batteries for extended range electric vehicles.

Alternatively, lithium-sulfur batteries based on multi-step redox conversion reaction provide a theoretical specific capacity of 1675 mAh/g. However LiS batteries also suffer from many problems, such as severe volumetric expansion/contraction during lithiation/de-lithiation, polysulfide (PS) dissolution and shuttling dendritic lithium growth on the anode, corrosion of aluminum current collector, low sulfur utilization and low current efficiency (CE).

In this manuscript, we demonstrate that specific types of sulfur allotropes react differently from standard orthorhombic sulfur used in state of art LiS batteries. Significant improvements are achieved by using sulfur allotropes as both cathode active mass and 3D structural additive. Dissolution of polysulfides is confined within the cathode by the use of a bi-functional additive capable of controlling cathode reaction and the first discharge plateau is extended to deliver a capacity of 408 mAh/g at 0.2C which is close to theoretical limit of 418 mAh/g for long chain PS (Fig.1). Instead of using various methods for controlling PS dissolution and migration which are mostly based on PS binding and interaction with host-catalyst structures, we used a bi-functional additive capable to control both reaction proceeding as well as its kinetics. This method allows PS dissolution but reactions are strictly limited into cathode compartment and cannot proceed outside the cathode. An important aspect of this approach is significantly reduced side-reaction between PS and electrolyte.

Fig.1: Comparison of discharge curves of standard electrode and electrode with bi-functional additive 0.7M LiTFSI + 0.25M LiNO3
, DOL/DME 2:1 v/v, active mass S loading bi-additive 1.95 mg/cm2, standard 1.65 mg/cm2

This research has been carried by Graphene Batteries AS in close cooperation with the Centre for Research and Utilization of Renewable Energy (CVVOZE) as a part of collaboration project NPU I programme (project No. LO1210), (project No. FEKT-S-14-2293)

Figure 1
Improving Metal Anode Stability in Potassium Oxygen Batteries with Concentrated Electrolyte
Authors: Ren Xiaodi , Lau Kah Chun , Wu Yiying
Published: February 2020

In recent years, metal-oxygen batteries, especially non-aqueous lithium-oxygen batteries (or Li-O2 batteries), have drawn considerable research attention for future energy storage applications due to high theoretical specific energy densities. Compared to conventional lithium-oxygen batteries, potassium-oxygen (K-O2) batteries are based on a reversible O2/KO2 redox chemistry, resulting in much better round-trip efficiencies (higher than 90%) without using electrocatalysts. While the reversibility of the cathode reactions is improved, the cycling performance of K-O2 batteries is greatly limited by the K metal anode stability. The highly reducing K anode would react with electrolyte molecules and degrade seriously during cycling. Moreover, the oxygen crossover to the anode further accelerate the degradation process.  Here, we report our studies about the improved K metal anode stability in K-O2 batteries with concentrated electrolytes. It is shown that in this class of electrolytes, a stable Solid Electrolyte Interface (SEI) layer is critical for protecting the K anode and suppressing the undesired side reactions. As a result, the metal anode cycling efficiency and the cycle life of K-O2 batteries can be largely increased.
Materials Selection and Chemistry Development for Redox Flow Batteries
Authors: Wang Wei , Wei Xiaoliang , Li Bin , Vijayakumar Murugesan , Nie Zimin , Sprenkle Vincent
Published: February 2020

Redox flow battery technologies are leading candidates for stationary energy storage, which provide a potentially cost-effective approach that would be beneficial for renewable energy integration, balancing the mismatch between supply and demand, as well as improving the overall reliability and efficiency of the grid. Until very recently, most research in this area has focused on aqueous electrolyte systems, with the choice of electroactive materials mostly focused on transition-metal redox species, such as the all-vanadium and Fe/Cr redox flow batteries. This choice limits aqueous systems to low energy density because of the low solubility of metal salts in water. Some of the high-cost transition-metal elements further limit the potential of cost reduction of the flow battery system.

Materials selection and chemistry development are therefore of critical important to expand the chemical space for the flow battery technology. Through a molecular ligand design approach, we demonstrate that the structure of organic and inorganic redox active species can be tuned to capture the most attractive properties, such as favorable potential, high solubility, and low cost, etc. In the Zn-I redox chemistry, alcohol (ethanol(EtOH)) can be used as a stabilizing agent to mitigate the triiodide dissociation and subsequent precipitation reaction through direct coordination of EtOH with the zinc cation (Figure 1).1 A new total organic aqueous redox flow battery (OARFB) has also been developed using low-cost and sustainable methyl viologen (MV, anolyte) and 4-hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl (4-HO-TEMPO, catholyte), and benign NaCl supporting electrolyte (Figure 2).2The electrochemical properties of the redox active materials and their performance in flow cell will be presented.

Figure 1 a. Triiodide complexed zinc cation and b EtOH-complexed zinc cation formed in the catholyte during the charging process. c. Efficiencies of the cell with (2.5 M ZnI2 + 10 vol% EtOH) and Nafion 115 as membranes tested under the current density of 10 mA cm-2at different temperatures.

Figure 2. Cyclic voltammograms of MV (blue trace) and 4-HO-TEMPO (red trace); conditions: 4.0 mM analyte in 0.5 M NaCl electrolyte; scan rate: 50 mV/s; glassy carbon working electrode; glassy carbon counter electrode; Ag/AgCl reference electrode.

Acknowledgements

The authors would like to acknowledge financial support from the U.S. Department of Energy’s (DOE’s) Office of Electricity Delivery and Energy Reliability (OE) (under Contract No. 57558). Pacific Northwest National Laboratory is a multi-program national laboratory operated by Battelle for DOE under Contract DE-AC05-76RL01830.

 
 

References

(1)        Li, B.; Nie, Z.; Vijayakumar, M.; Li, G.; Liu, J.; Sprenkle, V.; Wang, W. Nat Commun
2015, 6, 6303.

(2)        Liu, T.; Wei, X.; Nie, Z.; Sprenkle, V.; Wang, W. Advanced Energy Materials
2015, n/a.

Figure 1