bluuebunny/crossref_metadata_2025 huggingface dataset:
Bis(trifluoromethanesulfonyl)Amide-Based Room Temperature Ionic Liquid for Potassium-Ion Batteries
Authors: Yoshii Kazuki , Masese Titus , Shikano Masahiro
Published: December 2020

Rechargeable potassium-ion batteries are promising candidates for low-cost largescale energy storage systems due to their cost-effectiveness, sustainability and comparable energy density. With an increasing number of publications related to electrolytes for potassium-ion batteries, (1) room temperature ionic liquids (RTILs) have also been suggested as feasible electrolytes owing to their superior properties, such as non-flammability and wide electrochemical window.(2)In our research group, we reported bis(trifluoromethanesulfonyl) amide (TFSA)-based RTILs as suitable for the operation of potassium-ion battery when coupled to high voltage cathode materials.(3) In this study, we evaluate the physicochemical properties of TFSA-based RTILs with KTFSA, in addition to assessing their application for high-voltage potassium-ion battery with honeycomb layered cathode oxides. (4)

N-methyl-N-propylpyrrolidinium (Pyr13) TFSA and 1-ethyl-3-methylimidazolium (EMI) TFSA were selected as RTILs in this study. A comparison of their physicochemical properties with same concentration of KTFSA, LiTFSA, and NaTFSA reveal RTILs containing KTFSA to show relatively high ionic conductivity and wide electrochemical window. When a symmetrical cell of potassium was constructed using Pyr13TFSA with 0.5 M of KTFSA, deposition and dissolution reaction could be performed repeatedly without increase in overvoltage. Finally, we evaluated the charge/discharge performance of K2Ni2-x
Co
x
TeO6 (where x=0.25, 0.5 and 0.75) high-voltage cathode materials using Pyr13TFSA with 0.5 M of KTFSA as an electrolyte. Results show that each positive electrode has good cycle performance, and the average voltage changed depending on the Co content in the cathode. We conclude that TFSA-based RTILs are potential candidates for high-voltage potassium-ion battery.

References

1. T. Hosaka, K. Kubota, A. S. Hameed and S. Komaba, Chem. Rev. (2020).

2. T. Yamamoto, K. Matsumoto, R. Hagiwara and T. Nohira, J. Phys. Chem. C, 121, 18450 (2017).

3. T. Masese, K. Yoshii, Y. Yamaguchi, T. Okumura, Z.-D. Huang, M. Kato, K. Kubota, J. Furutani, Y. Orikasa, H. Senoh, H. Sakaebe and M. Shikano, Nat. Commun., 9, 3823 (2018).

4. K. Yoshii, T. Masese, M. Kato, K. Kubota, H. Senoh and M. Shikano, ChemElectroChem, 6, 3901 (2019).

Acknowledgement

This work was conducted in part under the auspices of the Japan Society for the Promotion of Science (JSPS KAKENHI Grant Numbers 19K15686).
Electrodeposition of Tantalum Coatings on Nitinol Stents
Authors: Kuznetsov Sergey , Makarova Olga , Dubrovskiy Anton
Published: December 2020

The Ni-Ti shape memory alloys are currently a topic of notable interest in medicine. They provide a unique opportunity to make novel surgical implants and instruments for vascular and orthopedic surgery. However, a high nickel content in these alloys could cause the problem of biocompatibility because of nickel toxic effect. In turn, a tantalum is successfully used in medicine as a wire or sheet. It does not irritate the living tissue and does not harm the functioning of the organism, but it has a high specific weight. Therefore, using of tantalum coatings on various materials is more appropriate than utilization of a bulk metal. Thus, it is necessary to improve a corrosion resistance of nickel-titanium alloys (nitinol) that can be achieved with applying of protective porousless tantalum coating.

For obtaining of tantalum coatings the NaCl-KCl-NaF(10 wt%)-K2TaF7(10 wt%) melt was used at a temperature 1023 K. Direct (DC), unsteady state (USC) and pulsed current (PC) were supplied for electrodeposition. A cathodic current density was changed from 5 to 200 mA/cm2 at the galvanostatic mode. The same cathodic current densities and the time of electrolysis (tel
= 0.5-5.0 s) with pauses (tp
= 1-5 s) were used at unsteady state and pulsed electrolysis. It was found that a pulsed electrolysis allow to produce coatings with lower roughness than galvanostatic electrolysis.

Electroreduction of tantalum complexes in chloride-fluoride melt at a nitinol electrode was investigated. A voltammetric curve registered at a nitinol electrode except of the electroreduction peak of tantalum fluoride complexes to tantalum has several peaks corresponding to the formation of intermetallic compounds of nickel and tantalum.

In the case of formation intermetallic compounds between a substrate and coating is an important aspect of the coating adhesion to substrate. The adhesion was measured by cross-sections method using a tester of adhesion Elcometer 107. The measurements showed that coatings obtained by DC and USC could be classified as adhesion to international standards ISO (1) and ASTM (4B). At the same time, coatings deposited on nitinol by PC have a maximum class of adhesion ISO (0) and ASTM (5B). These results were obtained for intermetallic compounds with a thickness around 1-2 μm.

Additional experiments were carried out for obtaining of thick layers of intermetallics and study their composition by SEM and EDX.

The porosity of tantalum coatings was determined by Erhard’s technique based on measuring a current dissolution at a certain potential, in which dissolves a substrate material and coatings remain passive.

Corrosion resistance of the composition tantalum coating-nitinol was studied in different corrosion media.
Ammonium·18-crown-6 bis(trifluoromethylsulfonyl)amide
Authors: Kawata Kio , Kitada Atsushi , Fukami Kazuhiro , Murase Kuniaki
Published: December 2020

Ammonium (NH4
+) ion has some unique properties as a charge carrier, i.e., natural abundance and lightweight properties. In addition, compared with metal cations (such as Li+, Na+, and K+), NH4
+ ion shows the highest intercalation potential and comparable cycling performance for Prussian blue-type positive electrode materials, KM[Fe(CN)6] (M = Ni and Cu).[1] More recently, the first rocking-chair-type NH4
+ ion battery has been proposed.[2] The electrolytes for NH4
+ ion batteries, however, have rarely been investigated except for aqueous solutions and solid state electrolytes [2,3]. Therefore, electrolytes which enable fast NH4
+ ion transport at medium temperatures, i.e. 100–200 °C, have been of great interest.

Molten salts, especially ionic liquids (ILs), have received considerable attention as novel electrolyte materials for future electrochemical devices owing to their various characteristics such as negligible volatility, low flammability, high thermal and electronic stability, and high ionic conductivity. We have lately reported a series of studies on a hydronium (H3O+) solvate IL, which is described as [H3O+·18C6]Tf2N (18C6 = 18-crown-6-ether; Tf2N = bis(trifluoromethylsulfonyl)-amide, Tf = SO2CF3).[4–6] In [H3O+·18C6]Tf2N, protic H3O+ ion (i.e., solute) is solvated by 18C6 ligand (i.e., solvent) to form a [H3O+·18C6] complex cation (i.e., solvate), and the counter anion is the Tf2N– anion.

It is well known that 18C6 features a six-oxygen cavity and matches well a C3v coordination with NH4
+ as well as H3O+, while the degree of off-center of [NH4
+·18C6] is larger than that of [H3O+·18C6]. As far as we know, however, NH4
+-based molten salts or ILs for electrolytes have never been reported, while alkyl ammonium-based ones have already been studied.[7]

Herein, we report synthesis and physicochemical properties of [NH4
+·18C6]Tf2N (Figure 1). We synthesized NH4Tf2N by neutralization of HTf2N with NH3 before adding equimolar amount of NH4Tf2N to 18C6 to obtain [NH4
+·18C6]Tf2N. A differential scanning calorimetry revealed that [NH4
+·18C6]Tf2N melts at around 100 °C (Figure 2). The ether-coordinated ammonium amide has potential applications as electrolyte materials toward a new class of ammonium ion batteries.

This work was supported financially by Grants-in-Aid for Scientific Research (B) (No.19H02490: A. K.) from the Japan Society for the Promotion of Science. A. K. also thanks the Joint Usage/Research Program on Zero-Emission Energy Research, Institute of Advanced Energy, Kyoto University (ZE2020A-09).

[1] C. D. Wessells et al., J. Electrochem. Soc., 159, A98 (2012).

[2] X. Wu et al., Angew.
Chem. Int. Ed., 56, 13026 (2017).

[3] R. C. T. Slade et al., J. Solid State Chem., 32, 87 (1980).

[4] A. Kitada et al., J. Electrochem. Soc., 165, H121 (2018).

[5] A. Kitada et al., J. Electrochem. Soc., 165, H496 (2018).

[6] K. Kawata et al., J. Electrochem. Soc., 167, 046508 (2020).

[7] J. Qu et al., Tribol.
Lett., 22, 207 (2006).

Figure 1
Investigation of the Electrochemical Kinetics of Aluminum Deposition from Ionic Liquids
Authors: Bottcher Rene , Mai Sebastian , Ispas Adriana , Bund Andreas
Published: December 2020

Aluminum is one of the first metals that has been successfully deposited from ionic liquids (ILs) and has been in the focus of intense research. However, the electrochemical kinetics of the aluminum deposition from ILs is still not fully understood.

This paper will discuss recent results from the authors’ lab on the electrochemical kinetics of the deposition of aluminium from 1-ethyl-3-methyl-imidazolium based ILs. Overpotential measurements and electrochemical impedance spectroscopy (EIS) experiments were employed to extract kinetic data from potential-time transients (see Fig. 1). The transients were interpreted in terms of different contributions to the total overpotential. This includes a detailed discussion of the Ohmic drop, charge transfer, concentration and nucleation overpotential. The charge transfer mechanism of aluminum was investigated in terms of the anodic and cathodic rate-determining step (RDS) and oxidation and reduction mechanisms are suggested. Density Functional Theory (DFT) calculations were performed to evaluate if the suggested mechanism is thermodynamically reasonable.

Fig. 1 Potential-time transient for a constant-current step (j = 1.25 mA cm-2) at an aluminum electrode in [EMIm]Al2Cl7 at 300 K. The inset shows the first 500 ms of the potential-time transient.

Figure 1
(Invited) Electrodeposition of Aluminium Containing Alloys from Molten Fluoride Electrolytes Containing Metal Oxides
Authors: Haarberg Geir
Published: December 2020

Aluminium is produced by the Hall-Heroult process by electrowinning in a molten fluoride electrolyte with dissolved alumina at ~950 oC. Several metallic impurities typically end up in the produced metal due to the fact that most metals are more noble than aluminium. Such co-deposition of metals may be utilized to form aluminium alloys. Another advantage is that many metal oxides are readily soluble in molten cryolite based electrolytes. The more noble metals will deposit at the limiting current density. The alloy composition is essentially determined by the bath concentration of the dissolved cations of the alloying element. Therefore it is possible to produce alloys of certain compositions by controlled addition of metal oxides. Interesting candidate alloying elements are silicon, iron, titanium and manganese but also exotic elements such as scandium are possible. Electrochemical studies were carried out in laboratory experiments and the behaviour of dissolved metal oxides was studied in industrial cells. High current efficiencies for the co-deposition of the alloying elements Si, Fe, Ti and Mn were confirmed. Significant savings for producing alloys by this method are expected.
The Effect of Sulfide Electrolytes on the Properties of the All-Solid-State Batteries
Authors: Yoon Da Hye , Park Yong Joon
Published: December 2020

All-solid-state batteries (ASSBs) based on inorganic solid electrolyte have attracted considerable attention because they can solve the serious safety problem of lithium ion batteries (LIBs) using flammable liquid electrolytes. Moreover, ASSBs are expected to demonstrate better long term stability and wider operating-temperature range compared to those of LIBs. However, sulfide electrolytes easily generate undesirable side reaction with oxide cathode due to their high reactivity, which leads to deteriorate the electrochemical performance of the cells. As an effective approach for this issue, surface modification with stable materials has been applied to cathode for the ASSBs to suppress the cathode/sulfide electrolyte interfacial-instability. The interfacial stability of the ASSBs is highly dependent upon the type of sulfide electrolytes as well, so the selection of sulfide electrolytes would be a key point for assembling the ASSBs. In this study, NCA cathodes were surface modified using Li2MoO4-LiI to stabilize the unstable cathode/sulfide electrolyte interface. Four types of sulfides were tested as electrolyte for the cells containing pristine and surface modified NCA to characterize the effect of sulfide electrolyte on the electrochemical performance of the ASSBs.
Electroanalytical Study of Active Species to Deposit Ti Alloy from 1-Butyl-3-Methylimidazolium Chloride-Aluminum Chloride Ionic Liquid
Authors: Shinde Pravin , Peng Yuxiang , Reddy Ramana G.
Published: December 2020

Understanding the electrochemical deposition of titanium and its alloy from the ionic liquid electrolyte is technologically very essential and necessitates a wide range of attention to gain more insights into their electrochemistry. In this work, the electrochemical behavior of titanium-chloroaluminate anion species in the Lewis acidic alkyl imidazolium-chloroaluminate ionic liquid electrolyte is investigated by electroanalytical techniques such as cyclic voltammetry (CV), chronoamperometry (CA), and chronopotentiometry (CP). The effect of scan rate on peak potential and peak current, constant current density, constant applied potential, and the electrolyte temperature are discussed. It is shown that the redox reaction of the Ti(II)/Ti(0) deposition from titanium hepta-chloroaluminate ([Ti(Al2Cl7)4]2−) anions is a quasi-reversible process with a 2-electron transfer reaction while that of Al(III)/Al(0) deposition from hepta-chloroaluminate ([Al2Cl7]−) anions proceeds through 3-electron transfer. The cyclic voltammograms indicated that the reduction of [Al2Cl7]− and [Ti(Al2Cl7)4]2− species to corresponding aluminum and titanium forms is a diffusion-controlled phenomenon. The diffusion coefficients of the titanium hepta-chloroaluminate anion are determined under the studied experimental conditions at different temperatures using CV and CP techniques.
Fluorescence Lifetime Imaging of Alkyl Ammonium Modified Self-Assembled Helicoidal Cellulose Nano Crystal Films: How Reactivity Controls Polymer Dynamics
Authors: Gilman Jeffrey W. , Easter Quinn T. , Chen Shawn H. , Stranick Stephan J. , Fox Douglas M , Obrzut Jan , Souna Amanda J. , Vu Huyen , Seethamraju Sindhu , Coughlin E. Bryan , Woodcock Jeremiah W.
Published: December 2020

Due to the large volume fraction of nanoscale-reinforcement in cellulose-rich CNC-polymer nanocomposites and the extensive surface area, nearly all the soft/polymeric phase is interfacial (interphase polymer) and therefore, under nanoconfinement. It is well-established that the dynamic properties of any interphase polymer are determined by the structure of the polymer and strength of the interactions with the hard phase, and can deviate significantly from that of the neat polymer. With optimal interfacial interactions, this leads to significantly enhanced performance in many natural composites, such as those found in crustacean and insects shells, and bone. Yet, the role of interfacial interactions, polymer structure, and nano-confinement in helicoidal cellulose nano crystal nanocomposites remains incompletely understood. Here, we use fluorescently labelled helicoidal cellulose nanocomposites and fluorescent lifetime imaging microscopy (FLIM) to study the nature of the effect of polymer structure (cross linked, blend) on the confinement effect in alkyl ammonium modified sulfate-CNC. nanocomposites.

Figure 1
Development of Nanomagnetic Fe-Pd Biocomposites
Authors: Aiello Ashlee , Morey Jennifer R. , Livi Kenneth J. T. , De Long Hugh C. , ElBidweihy Hatem , Cimpoiasu Elena , Trulove Paul C. , Durkin David P.
Published: December 2020

Cellulosic biopolymer materials, such as cotton and linen, have been shown to function well as a support matrix for the synthesis of metallic nanoparticles. Nanoparticles grown within the biopolymer matrix routinely exhibit uniform size (~5 nm diameter) and even distribution for a variety of metallic systems, including Fe-Pd. Our recent work reports the synthesis and characterization of lignocellulose-stabilized superparamagnetic Fe-Pd biocomposites well suited to a variety of applications, including catalysis, micro-robotics, and electromagnetic interference (EMI) shielding. In continuation of this research, we have examined the effects of the type of cellulosic material on the magnetic behavior using vibrating sample magnetometer (VSM) measurements. Additionally, we report the use of ionic liquid treatment to form layered biocomposites, including magnetic behavior characterization.
(Physical and Analytical Electrochemistry Division Max Bredig Award Address In Molten Salt and Ionic Liquid Chemistry) The Ionic Melting Pot: My Research in Molten Salts and Ionic Liquids
Authors: Dai Sheng
Published: December 2020

Molten salts and ionic liquids are a unique class of solvents that offer many advantages, such as negligible vapor pressures, wide liquidus ranges, good thermal stability, and tunable solubilities of both organic and inorganic species. This presentation will provide an overview of my research in the following five areas related to molten salts and ionic liquids: (1) speciation and thermodynamics of actinides and fission products in molten salts, (2) metal-ion extraction based on ionic liquids, (3) gas separation through functionalized ionic liquids, (3) synthesis of functional materials (e.g, carbon, porous materials) using molten salts and ionic liquids as reaction media, (4) electrolytes based on task-specific ionic liquids, and (5) emerging porous ionic liquids. The overall goal of my research is to investigate fundamental principles underpinning ionic media through tailored interactions for energy-related applications.
Influence of Relative Humidity on the Reaction Kinetics in Rubidium Silver Iodide Based All-Solid-State Battery
Authors: Akin Mert , Wang Yuchen , Qiao Xiaoyao , Yan Zhiwei , Zhou Xiangyang
Published: December 2020

Our previous study on a rechargeable rubidium silver iodide (RbAg4I5) based all-solid-state battery has shown an exponentially improved performance with increasing relative humidity (RH). Previous galvanostatic charge-discharge measurements revealed that while operating in an ambient environment with a relative humidity (RH) of 100%, the specific energy and energy density of the all-solid-state battery reached 68 Wh kg-1 and 400 Wh L-1, respectively; however, the specific energy decreased by 90% under 10% RH. Here, we investigated the effect of humidity on the electrochemical reaction kinetics in the RbAg4I5 based all-solid-state battery. Four-electrode conductivity measurements of the solid electrolyte unveiled that the humidity had no appreciable influence (~4%) on the conductivity, whilst series cell resistances of half cells evaluated from electrochemical impedance spectroscopy measurements change only 3% within an RH ranging from 35% to 100%. On the other hand, linear sweep voltammetry measurements of anode and cathode half cells showed that increasing the RH from 35% to 100% increased the exchange current density by three orders of magnitude. The relationship between the water vapor adsorption and reaction kinetics was examined by constructing water vapor adsorption isotherms. The trend of exchange current density was attributed mainly to the water adsorption/desorption at the electrode/electrolyte interfaces and a model was proposed to explain the impact of water adsorption on the electrochemical kinetics. These results suggest that the all-solid-state battery operates effectively when exposed to a high humidity environment and can be used in the applications requiring very high reliability.

Figure 1
Tuning Ionic Conductivity in Sodium Anti-Perovskite Ionic Conductors
Authors: Li Yiliang , Tsai Ping-Chun , Wang Fei , Kim Kwangnam , Halat David , Yin Liang , Lapidus Saul H. , Balsara Nitash P. , Reimer Jeffrey , Siegel Donald J , Chiang Yet-Ming
Published: December 2020

Anti-perovskite materials have recently attracted great interest as a family of non-flammable solid state electrolytes with high ionic conduction.[1] Typical solid-state electrolyte materials have temperature dependent ionic conductivity following linear Arrhenius behavior over a substantial range of temperature, corresponding to a constant activation energy Ea. However, we have discovered several anti-perovskite materials that have strong positive deviations from Arrhenius behavior, leading to rapidly rising ionic conductivities with increasing temperature.

Na3OCl and Na3OBr are typical anti-perovskite compositions with atomic structure shown in Figure 1a. Strong deviations from Arrhenius (linear) behavior were observed in the temperature dependent conductivity measured by impedance spectroscopy, where Na3OCl0.5Br0.5 reaches the highest ionic conductivity with increasing temperature, as shown in Figure 1b. The structural origins of such behavior, such as change of octahedral tilt systems and order/disorder phase transition, has been investigated using multiple temperature-resolved characterization methods including synchrotron XRD, NMR, dielectric property measurements, and calorimetry, and modeled using AIMD and DFT. This work will give insight to tuning solid state electrolyte with high ionic conductivity.

This work was supported as part of the Joint Center for Energy Storage Research, an Energy Innovation Hub funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences.

Figure : Temperature dependent ionic conductivity and atomic model of Na-based anti-perovskites.

Figure 1
(Keynote) Chemical and Mechanical Stability Issues at Electrolyte/Electrode Interfaces in Solid State Batteries
Authors: Ceder Gerbrand
Published: December 2020

Stringent chemical and mechanical constraints apply to the interfaces in solid state batteries. They have to be (electro)chemically stable against the chosen electrode materials and applied potentials. In addition, they have to be tolerant to the various mechanical issues that occur in solid state batteries such as electrode swelling/shrinking, stress concentrations at current focusing areas etc. I will present the requirements for chemically stable interfaces between various cathode and electrolyte materials and discuss to what extent coatings can address chemical incompatibility. For the lithium anode side I will present results from modeling to understand the interplay between current density, stress, and lithium growth through the electrolyte. Our results indicate that in good conductors stress build up to the point that it fractures the electrolyte is unlikely. We also find that conductivity of the solid electrolyte plays a central role in the mechanical reliability of a solid-state battery.
Computational Design of Cathode Coating Materials for All-Solid-State Lithium Ion Batteries with on-the-Fly Machine Learning
Authors: Wang Chuhong , Aoyagi Koutarou , Mueller Tim
Published: December 2020

All-solid-state lithium-ion batteries have attracted significant research interest in recent years. Solid-state electrolytes have emerged as an appealing alternative to flammable organic liquid electrolytes, with the potential to accommodate higher-voltage cathode materials and a metallic lithium anode. Despite the discoveries of solid electrolyte materials exhibiting superionic conductivities, capacity loss and rate performance degradation has been commonly observed due to the prevailing issue of electrolyte/electrode interface reactivity, which originates from abrupt electrochemical potential changes at the electrode-electrolyte interface. The cycling stability of solid-state lithium ion batteries can be improved through the use of interfacial coating materials, but computationally identifying materials with sufficiently high lithium-ion conductivity can be challenging. Methods such as ab initio molecular dynamics that work well for superionic conductors can be prohibitively expensive when used on materials that conduct lithium ions less well but are still suitable for use as interfacial coatings. We demonstrate a way to address this problem using machine-learned interatomic potentials models in the form of moment tensor potentials. To prevent the potentials from significantly deviating from density functional theory (DFT) calculations we use molecular dynamics simulations coupled with on-the-fly machine learning. The efficiency of the calculations is increased by seven orders of magnitude compared to pure DFT, allowing for significantly improved prediction accuracy relative to experimental benchmarks. Using this approach, we have identified two particularly promising materials, Li3B7O12 and Li3Sc2(PO4)3, that are predicted to enhance long-term cyclability. The top candidate, Li3B7O12, has outstanding interface stability and to our knowledge has not previously been investigated as a lithium-ion conductor.
Temperature-Dependent Atomistic Dynamics Correlated to Cation Transport in Cluster-Ion Anti-Perovskites
Authors: Tsai Ping-Chun , Li Yiliang , Wang Fei , Kim Kwangnam , Halat David , Yin Liang , Lapidus Saul H. , Balsara Nitash P. , Reimer Jeffrey , Siegel Donald J , Chiang Yet-Ming
Published: December 2020

As fast-ion conductors, cluster-ion anti-perovskites (APs) are attractive for potential new mechanisms of conduction whereby cation and anion motion is highly correlated [1,2]. Cluster-ion APs, like perovskites, have a framework that accommodates diverse atomic substitutions. Furthermore, the potential for cluster-ion substitution onto one or both anion sites (A and B in X3AB) provides additional compositional degrees of freedom. To identify model cluster-ion APs for understanding such conduction mechanism, we have synthesized and characterized ~20 cluster-ion APs compositions, from which Na3-x(NH2)xO1-x(BH4) has been identified as an ideal model system for understanding the correlation between cluster-ion rotation and cation transport as shown in Figure 1. Particularly, Na2(NH2)(BH4) exhibits an unusual positive deviation from ideal Arrhenius behavior indicative of a flattening of the energy landscape with increasing temperature. Concurrently, the sodium conductivity increases by 104 to 105, which is most likely due to some combination of the effects of Na vacancy introduction and NH2 and/or BH4 anion mobility. Herein, synthesis, property, and characterization of the cluster-ion APs, aimed at understanding the temperature-dependent atomistic dynamics and its effects on cation transport, will be discussed in the presentation.

This work was supported as part of the Joint Center for Energy Storage Research, an Energy Innovation Hub funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences.

Reference
s
:

[1] Hong Fang and Puru Jena. Li-rich antiperovskite superionic conductors based on cluster ions. Proceedings of the National Academy of Sciences, 2017, 114, 110461.

[2] Hong Fang and Puru Jena. Sodium Superionic Conductors Based on Clusters. ACS Appl. Mater. Interfaces. 2019, 11, 963-972.

Figure 1
Understanding the Structural Disorder Related to Ionic Conductivity Enhancement in Anti-Perovskite Ion Conductors
Authors: Wang Fei , Li Yiliang , Tsai Ping-Chun , Yin Liang , Evens Hayden , Kim Kwangnam , Lapidus Saul H. , Siegel Donald J , Chiang Yet-Ming
Published: December 2020

Amongst known families of solid electrolytes of potential interest for solid-state batteries, the anti-perovskites (APs) have recently attracted great attention for the high ionic conductivities observed in certain compositions, and, like perovskites, the compositional flexibility provided by the possibility for ion substitution onto multiple lattice sites. [1] For example, variations in the extent of disorder, that are accompanied by changes in the distribution of lithium migration energies.[2] In surveying transport in this family of ion conductors, we observed a trend wherein numerous compositions show upwards curvature on an Arrhenius plot, indicating a non-constant activation energy. This is unusual as most solids exhibiting non-Arrhenius behavior exhibit a negative deviation. The structure origins of such deviations are not well understood.

Among the AP-structure SSEs, Li2OHCl and its variants are particularly interesting because of their relatively high conductivities at room temperature. Unlike Li3OCl, where six Li atoms occupy the vertices of the Li6O octahedral, in Li2OHX the vertices are occupied by four lithium atoms with two other sites vacant. H in Li2OHX sits at the oxygen atom in the center of the octahedron. The Li defects and the movement of H around the oxygen atom give rise to a change in the ionic conduction pathway as temperature varies (Figure 1).

Figure 1. The ionic conduction pathway of Li and H in Li2OHCl at different temperature

Herein, we explain the non-Arrhenius conduction behavior in relation to defect and H movement, and our attempts to understand the structural origin(s) of this behavior through temperature-dependent X-ray and neutron scattering, calorimetry, and other methods. Implications for the design of solid electrolytes for solid state batteries will be discussed.

This work was supported as part of the Joint Center for Energy Storage Research, an Energy Innovation Hub funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences.

Reference
s
:

[1] Zhao, Y.; Daemen, L. L. Superionic conductivity in Lithium-rich anti-perovskites. J. Am. Chem. Soc. 2012, 134, 15042−15047.

[2] Kwangnam Kim and Donald J. Siegel. "Correlating lattice distortions, ion migration barriers, and stability in solid electrolytes." Journal of Materials Chemistry A 7, no. 7 (2019): 3216-3227.

Figure 1
Direct Measurement of Nano-Sized Lithium Dendrite Growth Stress By in-Situ TEM
Authors: Aubin Megan , Kushima Akihiro
Published: December 2020

The all-solid-state Li-ion battery is attracting attention because it enables the use of a high capacity Li metal anode while easing safety concerns by employing a stable solid electrolyte. It is expected that the use of a solid electrolyte with a high shear modulus would prevent the growth and propagation of destructive lithium dendrites. However, dendrites still penetrate solid electrolytes, causing the cell to short, and the exact mechanism is still under debate. Additionally, a large compressive stress is generally applied to the cell to maintain good contact between the electrode and the solid electrolyte, which may affect the lithium deposition process and the stability of the solid electrolyte. Therefore, understanding the relationship between the mechanical stress and lithium dendrite growth is key in decoding the dendrite penetration process.

We developed an in-situ transmission electron microscopy (TEM) technique to directly observe the early stages of the lithium dendrite growth process and obtain the initial force on a Li dendrite. Setup involved a sharp conductive cantilever tip contacting a relatively flat lithium metal surface and applying a potential bias initiating lithium plating at the tip. The in-situ TEM observation, as schematically illustrated in the figure below, commenced with dendrite nucleation (A) and progressed as a nano-sized lithium pillar growing vertically causing increasing stress (B). The dendrite continued its vertical growth until the force reached a critical value (C). The pillar then started to expand horizontally (D). The measured critical stress is much higher than the yield stress of bulk lithium, showing lithium can locally introduce high stresses on solid electrolytes without yielding. It is suggested that horizontal lithium growth helped to release dendritic stress buildup, unveiling a promising strategy to implement in future investigations of how to mitigate penetration through the solid electrolyte, preventing the dendrite from reaching the cathode and causing a catastrophic short. The information obtained in this work is useful for constructing a constitutive model of a lithium plating process in an all-solid-state system and understanding the mechanical stability of solid electrolytes particularly at the early stage of lithium deposition.

Figure 1
(Invited) Wetting Mechanism of Molten Lithium on Garnet-Type Solid Electrolytes
Authors: Yamada Hirotoshi , Ito Tomoko
Published: December 2020

Garnet-type solid electrolytes are one of key materials towards oxide-based all-solid-state batteries. Their superb electrochemical stability against lithium metal have driven ambition to employ lithium metal as large-capacity anode. However, poor contact between the garnet-type solid electrolytes and lithium metal causes large area specific resistance on lithium plating/stripping reaction, which is supposed to be one of reasons of lithium growth through the solid electrolytes. To achieve good contact, various processes have been proposed: polishing, vacuum deposition and/or interface layers.[1] Wetting the surface of garnet-type solid electrolytes with molten lithium is a simple but certain process to form dense interface between Li and garnet-type solid electrolyte. In this work, we report a mechanism of wetting of molten lithium on the garnet-type solid electrolytes. X-ray photoelectron spectroscopy of surface and interface of garnet-type solid electrolytes indicated a three-step wetting mechanism: (1) formation of Li2CO3 on garnet-type solid electrolytes, (2) reduction of Li2CO3 to form C by molten lithium, and (3) wetting of molten lithium on carbon formed on the solid electrolyte. Lithium ions are inserted to the carbon layer, which play a role of mixed ionic and electronic conductor. This mechanism can also explain the novel short-circuit mechanism without current.

References

[1] R.H. Basappa, T. Ito, H. Yamada, J. Electrochem. Soc. 164 (2017) A666–A671. doi:10.1149/2.0841704jes.
Crosslinked Single-Ion-Conductor Polymer Electrolytes
Authors: Jeanne-Brou Roselyne , Issa Sébastien , Devaux Didier , Grosso David , Phan Trang N. T. , Gigmes Didier , Bouchet Renaud
Published: December 2020

Liquid based electrolytes used in conventional Li-ion batteries are made of a mixture of Li salt and flammable alkyl carbonate solvents. In addition, their transference number (t
+) is low, typically 0.3, which limits the battery power performance because of the formation of strong gradient of concentration during operation.[1] To increase both safety of energy density a solution is to develop a Li metal based battery comprising a single-ion-conductor solid polymer electrolyte.[2]

Poly(ethylene oxide) (PEO) doped with a Li salt is the fundamental solid polymer electrolyte due to its high ionic conductivity (> 10-4 S/cm) above its melting temperature (> 60°C), and, chemical and electrochemical stability towards Li metal. However, its t
+ is low, about 0.15.[3] A strategy is then to develop a single-ion-conductor polymer electrolyte comprising PEO to ensure Li metal stability and battery operation at room temperature.[4]

In this study, we report on the facile synthesis and the physico-chemical and electrochemical characterizations of series of crosslinked single-ion electrolytes based on a PEO matrix. These materials are shown to be single-ion-conductors with interesting Li dendrite resistance. In addition, for these electrolytes a thorough study by impedance spectroscopy using symmetrical cells with either Li reversible electrodes or stainless steel blocking electrodes reveals a complex electrolyte resistance response composed of two contributions as encountered in materials with bulk and grains boundaries (Figure 1). We thus proposed a methodology to extract the grain and grain boundary contributions, which is essential to correctly determine in turn the electrolyte transport properties (transference number, diffusion coefficient). Furthermore, a discussion on the origin of this phenomena is proposed.

References

[1] K. Xu, Chem.
Rev., 104 (2004) 4303.

[2] R. Bouchet et al., Nat. Mater., 487 (2012) 1

[3] K. Pozyczka et al., Electrochim. Acta., 227 (2017) 127

[4] L. Long et al., J. Mater. Chem. A, 4 (2016) 10038

Figure 1
Digital Twin-Driven All-Solid-State Lithium-Ion Battery
Authors: Park Joonam , Kim Kyu Tae , Oh Dae Yang , Jin Dahee , Kim Dohwan , Jung Yoon Seok , Lee Yong Min
Published: December 2020

All-solid-state lithium-ion battery (ASLB) is one of the battery systems to have the most outstanding safety and energy density. In particular, the ASLB with solid sulfide electrolyte has been evaluated as a promising next-generation secondary battery thanks to solid sulfide electrolyte’s high intrinsic ionic conductivity and deformation property. However, the electrochemical performance of present ASLB like rate capability and cycle life is not a level to compete with anyone of commercial lithium-ion batteries because the design optimization of the all-solid-state electrode has not been completed. In other words, it is very important to understand the correlation of the electrode design and performance of the cell, however, it is extremely limited to analyze them only on the experimental process and discover better electrode designs. To lessen this difficulty, we successfully built up a digital twin ASLB that can confirm the phenomena inner ASLB such as ion flow, state of charge, and overpotential of active materials, etc. on 3D structure as well as predict its performance. The simulation results are also compared with the experimental data to verify the reliability of our digital twin model. We expect this approach not only must be used for the electrode design in ASLBs but also will be able to be utilized for other all-solid-state electrode systems.
Ceramic Composite Cathodes for All-Solid-State Lithium Batteries
Authors: Ihrig Martin , Tsai Chih Long , Finsterbusch Martin , Fattakhova-Rohlfing Dina , Guillon Olivier
Published: December 2020

Oxide-ceramic based all-solid-state lithium batteries (ASSLB) can provide high intrinsic safety, extended operational temperature range, and high energy density. As the first two are intrinsic to the materials system, one prerequisite to obtain high energy densities with such ASSLBs is the manufacturing of composite cathodes. Preferably, cathode active material (CAM) and electrolyte should form an intertwined 3D-network with an intimate extended contact between two phases. The interface between the CAM and the electrolyte should feature high total surface area with a low impedance to enable an efficient charge transfer and transport and minimize the resistance losses in a battery.

Composite solid cathode microstructures can be formed via a co-sintering of solid electrolyte and CAM powders. However, many CAMs such as Li[Ni1-x-yCoxMny]O2 (NMC), Li[Ni1-x-yCoxAly]O2 (NCA) or Li2NiMn3O8 (LMO) cannot withstand sintering temperatures required, for oxide class solid electrolytes as Li7La3Zr2O12 (LLZ) or Li1+xAlxTi2-x(PO4)3, to obtain sintered composite cathodes. Furthermore, the thermodynamic stability of CAMs significantly decreases in the presence of solid electrolytes. Still, several groups have demonstrated that thermodynamic limitations can be significantly lessened via a kinetic control of the process such as reduction of reaction times and a careful control of powder morphology during ceramic sintering process.

Following this work, we now demonstrate that FAST/SPS enables fabrication of different solid-state battery components within minutes such as a dense LLZ separator layer with a high ionic conductivity, a dense dual LiCoCO2 (LCO)/LLZ composite cathode without any interfacial reactions, and an integrated cathode half-cell consisting of a composite cathode and a LLZ separator layer at temperatures as low as 675 – 800 °C. Analyzing the structure, morphology, and electrochemical performance of the obtained components, we conclude that the impurities (carbonates) on the surface of LLZ powder play a decisive role in the formation of high-quality interfaces and the minimization of porosity. Furthermore, these impurities decrease the ionic conductivity at low sintering temperature and deteriorate the cycling stability of an ASSLB. High areal capacity of up to 4.0 mA h/cm2 at 80 °C with a constant current of 50 µA/cm2 and a good utilization of LCO was achieved for ASSLB with LLZ powders free of surface impurities. FAST/SPS can therefore open new processing windows for ceramic-based ASSLBs to alleviate the problem of interphase formation.
Improvement of ORR Activity and Durability of Pt Electrocatalyst Nanoparticles Anchored on TiO2/Cup-Stacked Carbon Nanotube in Acidic Aqueous Media
Authors: Matsumoto Futoshi , Ando Fuma , Gunji Takao , Ohsaka Takeo
Published: December 2020

Platinum nanoparticles (Pt NPs) have been selectively anchored by photodeposition on titanium oxide (TiO2) matrix which is formed by hydrolysis of titanium isopropoxide on cup–stacked carbon nanotubes (CSCNT) in isopropanol, producing the composite Pt catalyst useful for oxygen reduction reaction (ORR) in acidic media, i.e., Pt NPs/TiO2/CSCNT (Fig. 1). Using scanning transmission electron microscopy (STEM) with a high–angle annular–dark–field (HAADF) detector it has been clarified that Pt NPs are sunk into the TiO2 moieties and have the unique polyhedral shape surrounded mainly by the Pt (1 1 1) and Pt (1 0 0) facets. X–ray photoelectron spectroscopy (XPS) allowed us to confirm changes in electronic properties of both Pt NPs and TiO2 support, induced by the so-called strong metal–support interactions (SMSI) and the significantly increased ORR activity was attained in 0.1 M HClO4, compared with the Pt NPs deposited on CB (Vulcan carbon) and CSCNT. The surface structure of the Pt NPs was characterized by transmission electron microscopy (TEM), indicating the improved durability of the Pt NPs deposited on the TiO2/CSCNT, i.e., the only slight increase in the particle size after the durability test (typically 2000 times’ potential cycling at 10 mV s-1 in the potential ranges of 0.05 to 1.1 V and 1.0 to 1.5 V vs. RHE in 0.1 M HClO4). The results obtained demonstrate that the anchoring of Pt NPs on the TiO2 support material deposited on CSCNT is an effective way to enhance the ORR activity of Pt NPs by the SMSI as well as to prohibit Pt NPs from aggregating, i.e., the degradation of the ORR activity of Pt NPs.

Figure １ HAADF STEM images of Pt NPs/TiO2/CSCNT sample with (A) low- and (B) high-magnification. The high-magnification image in (B), which shows the assignment of the surface geometry of the Pt NPs deposited on TiO2/CSCNT, was collected from the selected area denoted by the dotted square in (A).

Figure 1
Vanadium Flow Battery Electrochemistry and Fluid Dynamics Model with in-Situ Current Distribution Validation
Authors: Ertugrul Tugrul Yavuz , Daugherty Michael , Aaron Douglas , Mench Matthew M
Published: December 2020

It has been estimated that the high penetration of renewable electricity generation (68%-73% from solar and wind) could be possible in the United States by 2050. To achieve this goal, large-scale energy storage technologies will play important role. Energy storage technologies can help to improve electricity stability, flexibility, reliability and resilience on the grid. Among different energy storage methods vanadium redox flow batteries (VRFBs) have been a recent focus of interest due to distinct advantages, i.e., flexibility and scalability, high columbic efficiency, and long cycle life. However, high system cost is a main challenge for widespread commercialization of VRFBs. Although the component costs (membrane cost and chemical cost) tend to dominate the overall system costs, it is possible to decrease costs by improving electrolyte utilization and system efficiency. This can be achieved through increasing vanadium solubility in the solvent, modifying membrane and minimizing crossover, facilitating electrochemical kinetics, improving mass transport and reducing parasitic pump losses. However, VRFB is a complex system with multiple interrelated parameters (mass transport and electrochemical reactions) affecting electrochemical cell performance; these interrelated parameters are difficult to disentangle experimentally. A comprehensive and suitably validated mathematical simulations can both help to understand complex phenomena inside the VRFB cell and provide practical knowledge for controlling and optimizing VRFB systems. In this study, three dimensional, steady-state multi-physics model is developed for VRFB strip cell architecture under the dilute solution theory assumption. The simulation domain includes membrane, electrodes, flow plates and current collectors. Continuum equations: conservation of mass, momentum, species and charge coupled with Butler-Volmer kinetics are employed. Polarization curve analysis and fully segmented, printed circuit board (PCB)-based, localized current distribution measurements are employed to validate the mathematical model. Good agreement is achieved between the model predictions and the experimental measurements. The model successfully predicts not only the charge-discharge polarization curve but also the current distribution along the channel.

Figure 1
A Study on the Electrochemical Performance of Fe-V Chloric/Sulfuric Mixed Acid Redox Flow Battery Depending on Electrode Activation Temperature
Authors: Lee Han Eol , Kim Dae Eop , Kim Taekeun
Published: December 2020

As the main component of the redox flow battery, the electrode has a great influence on the electrochemical performance of the redox flow battery. Among the several investigated electrodes, GFD 4EA was found to exhibit the highest capacity, coulomb efficiency, and energy efficiency when chloric/sulfuric mixed acid supporting electrolyte was used for Fe2+/Fe3+ and V2+/V3+ redox couple reactions. The selected electrode was further investigated for the effect of activation temperature.[1-3] Physical characteristics including the mass retention and surface functional oxygen group were analyzed for the samples obtained from the various activation temperature. For electrochemical analysis, electrochemical capacity, coulomb efficiency, and energy efficiency were evaluated depending on activation temperature.[4] The mass retention rates for the electrodes activated under 500 ℃ were over 99.0%, while 89.0 % and 58.3% for the samples activated at 600 ℃ and 700 ℃, respectively. The electrochemical capacity showed the increasing tendency as the increase of the activation temperature up to 400 ℃, then continuously decreased. The XPS analysis confirmed that the oxygen functional groups were sufficiently generated on the surface of the electrode during the high-temperature activation which results in the electrochemical performance. The energy efficiency showed maximum value at 500 ℃. It is considered that significant mass loss of the electrodes at high activation temperatures results in changes in the shape and structure of the electrode surfaces, thus decreased the electrochemical performances due to increased interfacial resistance.

References

[1]. B. Sun and M. Sykllaskazacos, Electrochim Acta, 37, 1253 (1992).

[2]. K. J. Kim, Y. J. Kim, J. H. Kim and M. S. Park, Mater Chem Phys, 131, 547 (2011).

[3]. A. M. Pezeshki, J. T. Clement, G. M. Veith, T. A. Zawodzinski and M. M. Mench, J Power Sources, 294, 333 (2015).

[4]. P. C. Ghimire, Nanyang technological university, 190 (2019).