Shuttle Battery Research Articles

Fluoride Shuttle Battery Reactions of CuF2: Intermediate Phase for Defluorination

Fluoride Shuttle Battery Reactions of CuF₂: Intermediate Phase for Defluorination

Study of Behavior of Supporting Electrolyte Ion of Fluoride Shuttle Battery Using Anomalous X‐Ray Scattering

Fluoride shuttle batteries (FSBs) are superior to lithium‐ion batteries (LIBs) in terms of high energy density, safety, etc. An electrolyte consisting of tetraglyme (G4) as a solvent molecule and triphenylboroxine (TPhBX) as an anion acceptor to improve the solubility of cesium fluoride (CsF) salt is a candidate of the electrolytes for FSBs. The low concentration of CsF in the electrolyte makes it difficult to study. Electrical X‐Ray total scattering and anomalous X‐Ray scattering (AXS) are powerful techniques for studying the local structures of electrolytes. This study shows that AXS measurement with a Cs K‐edge can clarify the local structure around very low atomic concentration (0.27 at%) Cs. The first‐neighbor distance and the coordination number suggest that Cs+ ions exist in the major Cs(G4)2+ complex together with the minor Cs(G4)+. The low‐Q peak observed in the scattering patterns can be attributed to the structure of alternating [TPhBX]F− and [Cs(G4)]+ (or [Cs(G4)2]+). The large sizes of cations ([Cs(G4)]+ and [Cs(G4)2]+) and anion [TPhBX]F− lead to a long correlation distance. This work presents the picture that the F− ions hop from TPhBX to [Cs(G4)]+ or [Cs(G4)2]+ toward the cathode and anode during charge and discharge, respectively.

Low-Cost Fluoride Source for Organic Liquid Electrolyte-Based Fluoride Shuttle Battery

The effects of using low-cost inorganic fluoride salts (i.e., KF or NaF) as fluoride sources in fluoride shuttle batteries (FSBs) on the electrochemical compatibility of BiF3 electrodes are investigated herein. The preparation of electrolytes containing saturated KF or NaF and 0.5 M 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridine (DiOB-Py) in G4 is described. For Py/NaF/G4, the discharge and charge reactions of BiF3 were hindered because of the low solubility of NaF as well as the low ionic conductivity of the electrolyte. However, inductively coupled plasma mass spectrometry (ICP-MS) analysis revealed that the solubility of KF in Py/KF/G4 was moderate and the ionic conductivity of Py/KF/G4 was promising. Higher oxidation and reduction peaks observed in the cyclic voltammograms of Py/KF/G4 than those of Py/G4 and Py/NaF/G4 are attributed to the enhanced electrochemical activity of the former. Consequently, the BiF3/C nanocomposite electrode exhibits good cycling capability in Py/KF/G4, with initial discharge/charge capacities of 316/218 mAh g−1, respectively. Moreover, the ICP-MS and Raman spectroscopy analyses revealed that defluorination reactions of BiF3 occur via a direct desorption mechanism. Py/KF/G4 is the first effective electrolyte based on a low-cost inorganic salt. FSBs exhibit improved performance in Py/KF/G4 compared with CsF salt systems, which warrants further investigation.

Fluoride-Ion Shuttle Battery with High Volumetric Energy Density

With the increasing development of electric vehicles and portable devices, there is a strong requirement for high-energy batteries. To improve battery energy, multielectron transfer electrode react...

X‐Ray Total Scattering of Electrolytes in Liquid‐Based Fluoride Shuttle Battery: Electrolyte Composition Dependence of the Low‐Q Peak

X‐ray total scattering is applied to a series of molecular liquids including the CsF salt, which is expected to be a promising electrolyte in fluoride shuttle batteries. These electrolytes are composed of solvent molecules and addition agents (AAs), together with CsF. Tetraglyme (G4) or γ‐butyrolactone (GBL) is used as a solvent molecule, and lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), triphenylboroxine (TPhBX), or lithium bis(oxaloto)borate (LiBOB) as an AA. It is found that an additional peak appears on the low‐Q side of the main peak by the addition of LiFSI, LiTFSI, or TPhBX to the solvent, which indicates that correlation between cation and anion molecules is induced by these AAs. Furthermore, the position and the intensity of this peak are changed by the addition of the CsF salt, suggesting the modification of the correlation in the presence of the Cs+ and F− ions.

Fluoride Ion Conductive Polymer Electrolytes for All-solid-state Fluoride Shuttle Batteries

Fluoride Ion Conductive Polymer Electrolytes for All-solid-state Fluoride Shuttle Batteries

Reversible Electrochemical Reaction of a Fluoride Shuttle Battery with a Bismuth(III) Fluoride Electrode and Electrolyte Containing Triphenylboroxine as an Anion Acceptor

AbstractWe previously developed a fluoride shuttle battery containing a bismuth(III) fluoride (BiF3) electrode; however, the battery exhibited several drawbacks including poor cycling performance and low practical capacity. In this research, to obtain a BiF3 electrode with high cycling performance and practical capacity, an electrolyte containing triphenylboroxine as an anion acceptor was used, as previously reported. Moreover, BiF3 was pulverized and adhered with conductive material using a planetary ball mill. The experimental results indicated that adhesion to the conductive material effectively increased the practical capacity of the BiF3 electrode. To increase adhesion of the conductive material with BiF3 particles, the rotation speed of the ball mill was increased. The resulting BiF3 electrode exhibited high practical capacity in the first cycle, which was maintained in the following cycle. X‐ray absorption fine structure analysis results supported the progress of the reversible electrochemical reaction of the BiF3 electrode during the cycling.

Redox Behavior of a CuF2/Cu Electrode for an All-Solid-State Fluoride Shuttle Battery

Introduction The popularization of electrified vehicles connected to the smart grid community systems with stationary energy storage has attracted much attention as one of the solutions to global environmental problems. The critical technologies for such systems are rechargeable batteries with energy densities higher than that of conventional Li-ion batteries (LIBs). Among various candidates, all-solid-state fluoride-ion batteries (FIBs) operated by fluoride-ion transport [1] are promising owing to an ultra-high theoretical energy density over 5000 Wh/L [2].The FIBs currently we refer to as Fluoride Shuttle Batteries (FSBs) [3] were previously reported as a primary battery [4]. For the development of rechargeable FSBs, both electrolytes with high fluoride-ion conductivity and active materials that undergo reversible fluorination/de-fluorination reactions are crucial. Fluorite- and tysonite-type fluorides have been investigated as potential solid electrolytes since around the 1970s [ 5 , 6]. Recently, our group reported a series of PbxSn2-xF4 (x = 0.96~1.52) compounds [7] with a unique structure consisting of two alternating layers; a double Pb layer and a triple-layer, each flanked by a single Sn layer. The highest conductivity of 1.1 × 10-1 S/cm at 140 °C was achieved for fluorite-type Pb1.2Sn0.8F4 (x = 1.2). As for tysonite-type fluoride, Reddy et al. reported a possible rechargeable FIB using a La0.9Ba0.1F2.9 solid electrolyte [1] in combination with the various metal fluoride active materials such as CuF2, BiF3, and KBiF4. Among many metal fluorides, CuF2/Cu is a fascinating redox couple as the cathode active material owing to its large theoretical capacity (843 mAh/g) and high electro-motive-force (3.5 V vs. Li/Li+) [8]. However, full utilization of their theoretical capacity has not yet been demonstrated. In this study, we investigated the possible rate-determining steps in the CuF2/Cu cathode reaction using Pb1.2Sn0.8F4 (x = 1.2) with a high fluoride-ion conductivity. Experimental The Pb1.2Sn0.8F4 electrolyte was prepared by solid-state reaction using a mixture of PbF2 and SnF2 powders [7]. The fluoride-ion conductivity was measured by electrochemical impedance spectroscopy. The electrochemical cells were prepared by pressing into a 10 mm diameter pellet. Here, the cathode material was assembled using Cu, Pb1.2Sn0.8F4, and C in a 25:70:5 wt% ratio to facilitate both electronic and ionic conduction. Charge/discharge measurements were performed at 140 °C. Structural and electrochemical characterizations were conducted using TEM/SAED and operando XAFS. Results and Discussion The initial charge/discharge curves at 140 °C for the Cu cathode versus the PbF2 anode are shown in Fig. 1. The Cu cathode with Pb1.2Sn0.8F4 electrolyte exhibited a large charge (discharge) capacity of 522 (342) mAh/g. This capacity corresponds to 62 (41) % of the theoretical specific capacity even though the ionic conductivity of Pb1.2Sn0.8F4 was approximately 1000 times higher than that of La0.9Ba0.1F2.9 [1]. The Cu K-edge XAFS measurements during the charging process revealed the oxidation of Cu from Cu0 to Cu2+, and vice versa during the discharging process. The isosbestic points observed for all the spectra indicated that the conversion reaction involved the two phases, in agreement with the results of our DFT calculations [9]. In the TEM/SAED patterns of the cathode after charge, the distinct diffraction spots related to the CuF2 phase were observed on the surface of the metallic Cu particle. The fluoride-ion conductivity of CuF2 was 10-11 S/cm at 140 °C, which was very low compared to Pb1.2Sn0.8F4 and La0.9Ba0.1F2.9. These results suggest that the solid electrolyte may not be a dominant factor in the reaction on the cathode side, and alternatively smooth fluoride-ion diffusion inside the Cu active material plays a key role for redox behavior. As a next step, it may be effective to make the Cu active material a nano-composite with other fluorides, which is currently underway. Acknowledgments This work was supported by the New Energy and Industrial Technology Development Organization (NEDO) of Japan under the RISING and RISING2 projects.

(Invited) Novel Fluoride Batteries, Fluoride Shuttle Batteries, and Their Positive Electrodes

Progress of battery technology has opened new applications, which requires development of batteries of high performances, especially high energy density. There are two directions to improve the energy densities, i.e., enhancing cell voltage and increasing capacity of active materials. High cell voltage meets, however, the difficulty of stability of electrolyte.Batteries based on rocking-chair type reactions are limited in their capacity due to requirement of host lattice. On the other hand, conversion type active materials including traditional dissolution-deposition type ones can give higher capacity by using multi electron reactions. Anion mediating system may be able to be operated various metal electrodes using the common charge carrier. Among anion mediating systems, fluoride mediating systems, fluoride shuttle batteries (FSBs), give high capacity because metal fluoride is generally low formal weight.The authors’ group has focused on developing FSBs based on reactions of metal fluoride and metal, MFm/M. Metal fluoride are usually insulator, while some metal fluorides show ionic conductivity for F-. In this talk BiF3 and CuF2 are focused as positive active material. Electrolyte is a key material for activation of MFm/M electrodes. Solid electrolyte, liquid electrolyte including IL, and polymer electrolyte have been examined.Addition of anion acceptors to organic electrolyte enhances charge and discharge performances of BiF3/Bi electrode. The selection of adding anion acceptors is critical for each MFm/M electrode. The addition of anion acceptor, fluorobis(2,4,6-trimethylphenyl)borane, in tetragryme-CsF electrolyte increases remarkably the capacity and cyclability of BiF3/Bi electrode1). Copper fluoride is known as a typical insulator and when Cu electrode is oxidized to CuF2 only the skin-layer of Cu metal, ca. 6 nm, is oxidized to CuF2 and is passivated using lanthanum fluoride solid electrolyte operated at 140 oC. The addition of BaF2 to CuF2 powder activates CuF2/Cu electrode2). Konishi, T. Minato, T. Abe, Z. Ogumi, J. Electrochem. Soc., 2017 161, A3702.Morita, T. Abe, Z. Ogumi, et al., in preparation

Defluorination/Fluorination Reaction of BiF3 Nanoparticles Prepared Via Sol–Gel Method for Fluoride Shuttle Battery

Introduction Rechargeable batteries with high energy density have been required for recent applications such as hybrid electric vehicles and large-scale energy storage. Rechargeable batteries based on fluoride shuttle (FSBs) have attracted much attention as a candidate above, owing to their high theoretical energy density by selecting appropriate metal/metal fluoride couples as active materials of negative- and positive-electrode[1-3]. One of the important things of the battery is adoption of the good conductive media for fluoride species, that is, an electrolyte[4]. Another is reversible fluorination/defluorination of active materials at the interface with electrolyte. Previously, we have demonstrated archetypal reversible FSB using a liquid electrolyte containing organic fluoride at room temperature[3]. However, this battery needed to improve the utilization and cyclability of its active material. Since the common metal fluoride shows low electronic- and ionic-conductivity, the active materials should be minified for FSBs. In this study, metal fluoride nanoparticle, e.g. BiF3, was prepared via sol–gel method using a trifluoroacetate precursor for improvement of the charge/discharge reactions in FSB. Bismuth trifluoride having 302 mAh/g in theoretical capacity is considered as a candidate for positive active material[1-6]. Then, we studied reversible defluorination/fluorination reaction of thus prepared BiF3 nanoparticles in a liquid electrolyte of FSB at room temperature, and valence change of bismuth species in the consequent electrode was evaluated using synchrotron ex-situ XANES measurement.Experimental Bismuth trifluoride nanoparticle was prepared from bismuth trifluoroacetate precursor via decarboxylation at 453 K in an oleylamine solution under argon atmosphere. At that time, specific amount of trifluoroacetic acid and/or trifluoroacetic anhydride were added as a supplementary fluorine source. After the nanoparticles were precipitated via addition of toluene and ethanol sequentially, the resulting precipitation was centrifuged and then re-dispersed in toluene containing oleic acid as a dispersant. Finally, nanoparticles were obtained after stripping of ligand using a trimethyloxonium tetrafluoroborate. Size of the resulting nanoparticles can be controlled by precursor concentration, decarboxylation reaction time and its temperature. Electrochemical measurement was carried out using a three-electrode cell with a VSP-300 BioLogic potentiostat/galvanostat in an argon-filled glove box at room temperature. The cell was composed of a carbon cloth as a counter electrode, a silver wire as a quasi-reference electrode, and an ionic liquid containing an organic fluoride as a liquid electrolyte. The liquid electrolyte was prepared by dissolving N-methyl-N-propylpiperidinium fluoride (MPPF) or N,N,N-trimethyl-N-neopentylammonium fluoride (NpF) in N,N,N-trimethyl-N-propylammonium bis(trifluoromethanesulfonyl)amide (TMPA-TFSA) with molar ratio of 1:10. Nanoparticles-supported carbon cloth electrode as a working electrode was prepared by soaking the cloth in BiF3-nanoparticles/acetonitrile dispersion. The prepared nanoparticles via the sol–gel method and the defluorination/fluorination products in electrochemical measurements were evaluated using XRD, XPS, SEM-EDS, and so on in our laboratory. Furthermore, valence change of bismuth species was evaluated using synchrotron ex-situ XANES measurement at SPring-8, Japan.Results and Discussion Thus obtained nanoparticles via above-mentioned procedure had a few tens of nanometers in diameter and showed low crystallinity. Moreover, it was suggested that small amount of oxygen would be doped into the nanoparticles according to elemental analyses. Then, non-doped BiF3 nanoparticles having hexagonal crystalline structure had been acquired after further fluorination-treatment. Consequent BiF3 nanoparticles-supported carbon cloth showed ca. 240 mAh/g (80%) as an initial discharge capacity, and retained ca. 100 mAh/g for more than five cycles at room temperature. Furthermore, in ex-situ bismuth L3-edge XANES spectra, valence of bismuth species changed from trivalent to zero (metal) during the defluorination reaction and similar reverse change was elucidated in fluorination reaction. In this way, the size of the active material was minified by the preparation method, thereby improving the utilization and cyclability in FSB. This method will be also applied for other positive- and negative-active material having high gravitational theoretical capacity.Acknowledgements This work was supported by the “Research and Development Initiative for Scientific Innovation of New Generation Batteries 2 (RISING2)” of the New Energy and Industrial Technology Development Organization (NEDO), Japan.

Development of Cu-Based Positive Electrode for an All-Solid-State Fluoride Shuttle Battery

For the development of batteries with higher energy density, we have been developing all-solid-state fluoride shuttle batteries (FSBs) in RISING2 project of NEDO, Japan. Here we report the reversible electrochemical fluorination/de-fluorination of copper-based positive electrode using operando XAFS (X-ray absorption fine structure) measurement during charge/discharge processes. The Operando XAFS measurements were performed at the BL28XU of SPring-8, Japan. Based on the XAFS results, we have tried to improve the utilization of the active material by devising the electrode manufacturing method.The CeF3/Ce0.95Ba0.05F2.95/Cu cell showed 680 mAh/g(Cu) charge capacity and 593 mAh/g(Cu) discharge capacity, which was higher capacity than that of the previous works [1,2]. During the charge process, the operando XAFS spectra showed that pre-edge and white line peak intensity decreased and increased in proportion to the charge capacity, respectively, indicating that Cu converts to CuF2. On the other hand, the changes of XAFS spectra were opposite during the discharge process. These results indicate that this positive electrode is highly reversible for fluorination/de-fluorination reaction of Cu. However, some Cu metal remained at the full charge state because the charge capacity didn’t reach to the theoretical specific capacity (843 mAh/g), which was also confirmed from the XAFS spectrum.Other details will be shown in the conference. Acknowledgments This work was supported by the New Energy and Industrial Technology Development Organization (NEDO) of Japan under the Research and Development Initiative for Scientific Innovation of New Generation Battery (RISING2) project.

Electrochemical Performance of BiF3‐BaF2 Solid Solution with Three Different Phases on a Fluoride Shuttle Battery System

AbstractSolid solution of bismuth(III) fluoride (BiF3) and barium(II) fluoride (BaF2) with a variety of crystal structures was prepared, and their electrochemical performances were evaluated on a fluoride shuttle battery (FSB) system. BiF3‐BaF2 based solid solution (Bi1‐xBaxF3‐x (x=0) with orthorhombic phase, x=0.2 with hexagonal phase, and x=0.4 with cubic phase) were successfully obtained with the mechanical alloy method. The change from Bi1‐xBaxF3‐x (x=0) (orthorhombic) to x=0.2 (hexagonal) improved the initial reversible capacity and the capacity retention during cycling. The change from x=0.2 (hexagonal) to 0.4 (cubic) led to further improvement in capacity retention during cycling; however, the initial reversible capacity decreased due to the substitution of excess amount of barium that did not contribute to the redox reaction. For the BiF3‐based compound, controlling the crystal structure and substitution of inactive element affected the FSB performance.

Reactivity and Mechanisms in Fluoride Shuttle Battery Reactions: Difference between Orthorhombic and Cubic BiF3 Single Microparticles

BiF3 is a strong candidate for a cathode material in fluoride shuttle batteries (FSBs), which utilize defluorination of metal fluorides and fluorination of metals. Much interest has been shown in F...

Charge and Discharge Reactions of a Lead Fluoride Electrode in a Liquid‐Based Electrolyte for Fluoride Shuttle Batteries:‐The Role of Triphenylborane as an Anion Acceptor‐

AbstractLead fluoride (PbF2) is a promising electrode material for fluoride shuttle batteries (FSBs) owing to its high theoretical capacity (219 mAh g–1). In this study, the discharge and charge capacities of a PbF2 electrode were measured using a bis[2‐(2‐methoxyethoxy)ethyl] ether containing cesium fluoride and triphenylborane as an electrolyte. A high specific capacity was maintained during both the discharge and charge processes in the first cycle, but the capacity decreased from the first charge process to the following discharge process. To clarify the electrochemical reaction mechanism, the dissolution and change in the electronic state of Pb at the PbF2 electrode during the discharge and charge processes were evaluated via atomic absorption spectrometry (AAS) and X‐ray photoelectron spectroscopy (XPS). The results obtained from AAS and XPS indicated that Pb was formed during the discharge process. Conversely, the formation of PbF2 and dissolution of Pb coexisted within the wide range of charge process. The PbF2 could react in the following cycle, but the dissolved Pb was unable to contribute to the following discharge/charge reaction. Therefore, after the initial charge process, the capacity decreased.

Influence of Electrolyte Composition on the Electrochemical Reaction Mechanism of Bismuth Fluoride Electrode in Fluoride Shuttle Battery

Fluoride shuttle battery (FSB) is a promising next-generation battery candidate. In the FSB, metal fluoride and organic solvent containing supporting electrolyte salt and anion acceptor were used a...

Fluoride Shuttle Batteries by Liquid Electrolytes

Rechargeable batteries with fluorides as charge transporting ions, which we refer to as fluoride shuttle butteries (FSBs, see Fig. 1), potentially offer a high electrochemical energy storage capability that overwhelms those of the state-of-the-art lithium-ion batteries (LIBs). This is due to the unique properties of monovalent fluoride ions, which are lightest of halides, hardly oxidized, and yet capable of reacting with various metals to form mono- and multi-valent fluoride salts. They thus allow anion-based, multi-electron transfer, redox reactions under wide potential window. Besides, FSBs as such no longer require host lattices (prerequisite in LIBs), which further adds to the high energy density. The fundamental concepts and some successful examples of FSB systems that had been developed in the RISING battery project were addressed by one of the present co-authors (Z. Ogumi) in IBM2017 and IBA2018. We here focus on the recent advance in liquid-type FSBs that came out through the continued RISING2 battery project. It should be noted that none of alkali fluorides are soluble in common buttery-oriented organic solvents no matter how large static dielectric constants they have. Used as alternative electrolytes have thus typically been organic fluoride salts (such as alkylammonium or substituted alkylammonium fluorides) in combination with preferably ionic liquids. Another, more-or-less sophisticated, way out is to utilize so-called anion receptors that make even alkali fluorides substantially soluble in common organic solvents. We here show nonaqueous plain liquid fluoride electrolytes, which, according to our comprehensive and careful analyses, are apparently free from any addenda but somehow solvated Cs+ (or K+) cations and F- anions at a molar concentration of ~50 mM to give total ionic conductivity of typically ~0.8 mS/cm. The simple electrolytes exhibit versatile performance to make a variety of combinations of electrodes (ranging from Au/AuF3 to at least Zn/ZnF2) work reversibly in terms of the expected conversion reaction between the respective metal and its fluoride counterpart.Acknowledgement This work was supported by the Research and Development Initiative for Scientific Innovation of New Generation Battery 2 (RISING2), financially supported by New Energy and Industrial Technology Development Organization (NEDO). Figure 1

Evolution of Reactions of a Fluoride Shuttle Battery at the Surfaces of BiF3 Microclusters Studied by In Situ Raman Microscopy.

Fluoride shuttle batteries (FSBs), which utilize defluorination of metal fluorides and fluorination of the resultant metals, are expected to have high energy densities. In situ Raman microscopy was conducted during FSB reactions of a nearly-2D cluster of orthorhombic BiF3 microparticles partly embedded in a gold-plated film (o-BiF3 /gold). At a high overpotential, defluorination of the surface of an o-BiF3 particle (or cluster) was almost completed within approximately 120 s. At a low over potential, defluorination proceeded from the contours of the cluster that was in contact with the gold to the center of the cluster, suggesting that the rate-limiting process was electronic diffusion. Conversely, fluorination proceeded uniformly at the surface of the cluster to form BiF3 with a cubic structure (c-BiF3 ). The results will lead to the establishment of a strategy for efficient use of active materials with low electronic and ionic conductivities.

In Situ Observation of Fluoride Shuttle Battery Reactions with Dissolution-Deposition Mechanisms by Raman Microscopy

Fluoride shuttle batteries (FSBs) are expected to have high energy densities. Evolution of FSB reactions, defluorination and fluorination of a nearly two-dimensional cluster of orthorhombic BiF3 microparticles partly embedded in a gold plating film (o-BiF3/gold) was studied by in-situ Raman microscopy. Solutions of fluorobis(2,4,6-trimethylphenyl)borane (FBTMPhB) and CsF (0.45 M and about 0.5 M (saturation)) in tetraglyme were used as electrolytes. During defluorination in the 0.45 M CsF solution, metallic bismuth appeared not only at positions of the cluster but also at positions of the gold plating, accompanying changes in morphology of the cluster, indicating that a dissolution-deposition mechanism (BiF3 → Bi3+ + 3F−, Bi3+ + 3e− →Bi) was operative in defluorination. Deposition of metallic bismuth preferentially occurred in the vicinity of the cluster, resulting in extension of protruding areas on the surface. BiF3 with a hexagonal structure appeared during fluorination together with change in the morphology of the cluster. With 0.5 M CsF solution, changes in morphology of the cluster during defluorination and fluorination were small, suggesting that the contribution of the dissolution-deposition mechanism was small. The observed changes in distribution and morphology of active materials will be useful information for designing better electrolytes and electrodes in future batteries.

Triphenylboroxine and Triphenylborane as Anion Acceptors for Electrolyte in Fluoride Shuttle Batteries

For liquid-based fluoride shuttle batteries, electrolyte composed of organic solvent and supporting electrolyte salt is developed. To increase the solubility of supporting electrolyte salt in organ...

Lithium–Air Oxygen Shuttle Battery with a ZrO2‐Based Ion‐Conducting Oxide Electrolyte

AbstractInvited for this month’s cover is the group of Prof. Tatsumi Ishihara from Kyushu University, Fukuoka (Japan). The cover picture shows the newly proposed concept of an “oxygen shuttle” for a Li–air battery, in which a stabilized ZrO2 ion conductor is the electrolyte, and the red balls represent oxygen molecules that permeate through the electrolyte. Read the full text of the article at 10.1002/cplu.201402041.