bluuebunny/crossref_metadata_2025 huggingface dataset:
Electrochemical Bechaviour of Cobalt and Tungsten Oxides in Molten Carbamide
Authors: Devyatkin Sergei Vladimirovich , Kochetova Svetlana , Pisanenko Alexandr Dmitrievich , Bogdanovich Ludmila Vasilevna , Bykov Valeriy
Published: December 2020

The electrodepositions of tungsten and its alloys has been of considerable interest because of usual properties of the metal and alloys. The electrodepositions of W and Co from water solutions and Na2WO4-WO3-CoO at 1023 K were investigated in more works. The possibility of electrodeposition of W-Co alloys from carbamide melts at 408 K has been examined. When studying the electrochemical behaviour of cobalt and tungsten oxides and its compounds (WO3, Li2WO4, Na2WO4, K2WO4) in molten carbamide, it can be concluded that maximum limiting currents are typical of the system (NH2)2CO-Li2WO4. Cyclic voltammograms showed the potentials of deposition of tungsten and cobalt. Layered Co-W coatings on nickel cathodes have been obtained by the electrolysis of the molten system (NH2)2CO-CoO- Li2WO4 at current densities of 5-10 mA/cm2. The cathodic products were analyzed by XRD and JEM-2100F SEM.

Fig. SEM of the surface morphology of W-Co coating deposited by electrolysis from (NH2)2CO-CoO- Li2WO4 melt.

Figure 1
Electrochemical Behavior of Titanium Complexes in the KCl-KF Melt with Additions of Alkaline Earth Metal Cations
Authors: Vetrova Daria A. , Kuznetsov Sergey
Published: December 2020

The goal of the present investigation was to study of Mg2+, Ca2+, Sr2+ and Ва2+ strongly polarizing cations influence on the standard rate constants of charge transfer (ks
) for the redox couple Ti(IV)/Ti(III) in the KCl-KF(10 wt.%)-K2TiF6 melt.

Electrochemical studies were carried out in the temperature range of 1073-1173 K by cyclic voltammetry. Voltammetric curves were recorded at a glassy carbon electrode vs. a glassy carbon quasi-reference electrode. The sweep rate (v) varied from 0.1 up to 2.0 V s-1. The electrochemical redox process Ti(IV)+e-↔Ti(III) was classified as quasi-reversible at a sweep rate 1.0 V s-1≤ν≤2.0 V s-1.

The values of k
s were calculated by using the Nicholson’s method [1]. It was shown that k
s increase with increasing the temperature. It is due to the number of particles capable of overcoming the potential barrier increases [2].

Addition of alkaline earth metal cations resulted in increasing of ks
up to the certain ratio of Me2+/Ti(IV) for all alkaline earth metal cations. It was determined the linear dependence of ks
on ionic potential of alkaline earth metal cations.

The activation energies of the charge transfer in the case of strongly polarizing cations addition were calculated. It was shown that values of the activation energy for molten systems with strongly polarizing cations are considerably less than activation energy of the initial melt and decrease with increasing of ionic potential.

It was determined that the k
s for the redox couple Ti(IV)/Ti(III) in the KCl-KF(10 wt.%)-K2TiF6 melt (for all systems) are less than k
s in the NaCl-KCl based melt [3].

References:

[1] R.S. Nicholson, J. Anal. Chem., 1965. Vol. 37 (1965), 1351.

[2] B.B. Damaskin, O.A. Petriy, Introduction of electrochemical kinetics, Vysshaya Shkola Publ., Moscow, 1975 (in Russian).

[3] D.A.Vetrova, S.A. Kuznetsov, Proceedings of the Kola Science Center RAS, 2015. P. 214.
Ionic Liquids at the Electrode Interface: Insights into Surface Passivation and Framework Expansion of Hard Carbon Anodes
Authors: Bridges Craig A. , Sun Xiao-Guang , Guo Bingkun , Heller William , He Lilin , Paranthaman Mariappan Parans , Dai Sheng
Published: December 2020

Ionic liquids are being extensively explored as an alternative to carbonate-based electrolytes in reversible batteries, as they can exhibit lower flammability and volatility, and better overall safety. The polarity and acidity/basicity of ionic liquids can be tuned to control solubility, and can influence the electrochemical window and interfacial properties when used in batteries. In this study, 1-ethyl-3-methyl-imidazolium bis(trifluoromethanesulfonyl) imide (EMIM.TFSI) and 1-methyl-1-propypyrrolidinium bis(trifluoromethanesulfonyl)imide (MPPY.TFSI) were selected because they are well-known, relatively stable ionic liquids with large electrochemical windows which show strikingly different behavior with carbonaceous anodes due to differences in interface passivation. High surface area mesoporous hard carbon anodes were employed to provide a large signal from the interfacial chemistry of these electrolytes during reversible cycling. A combination of operando small-angle neutron scattering (SANS) and ex-situ electrochemical studies were used to understand the differences in solid electrolyte interphase (SEI) for these ionic liquids, and the relationship of SEI formation to hard carbon microstructural changes. Reversible hard carbon expansion is observed in the first cycle for the electrolyte lithium bis(trifluoro-methanesulfonyl)imide (LiTFSI)/EMIM.TFSI related to EMIM+ intercalation and deintercalation before a stable SEI is formed, while a largely irreversible framework expansion of 15% is observed for the LiTFSI/MPPY.TFSI electrolyte. There is only relatively minor expansion and contraction in subsequent cycles after a suitable solid electrolyte interphase (SEI) has formed. Irreversible framework expansion in conjunction with SEI formation is found to be essential for the stable cycling of hard carbon electrodes.[1]

Acknowledgement: Research was sponsored by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Materials Sciences and Engineering Division. Research at Spallation Neutron Source user facility was sponsored by the Division of Scientific User Facilities, Office of Basic Energy Sciences, US Department of Energy, under contract DE-AC05-00OR22725 with UT-Battelle, LLC.

[1] Bridges, C.A.; Sun, X.G.; Guo, B.K.; Heller, W.T.; He, L.L.; Paranthaman, M.P.; Dai, S. “Observing Framework Expansion of Ordered Mesoporous Hard Carbon Anodes with Ionic Liquid Electrolytes via in Situ Small-Angle Neutron Scattering.” ACS Energy Lett.
2017, 2, (7), 1698-1704.
(Invited) An Electrochemical Approach to Graphitization Via Molten Salts
Authors: Dai Sheng
Published: December 2020

Graphite is considered by the US Department of Energy to be a critical element. Due to its widespread use as anodes in batteries, the demand for high purity graphite for battery applications is expected to increase for the foreseeable future. Synthetic graphite, due to its high purity, is generally the preferred choice for battery applications. The current process for the synthesis of graphite is very energy intensive and requires heat treatment of carbon precursors to temperature up to 3300 K for successful graphitization. Herein, an electrochemical method for graphitization is reported, which requires significantly lower temperatures. The cathodic electrochemical polarization of amorphous carbons in molten salts at around 1100 K can transform amorphous carbons to highly graphitic carbon structures. This process is facilitated by molten salts and has the great potential to save significant energy compared to the current existing process.
(Invited) Soft Materials Containing Ionic Liquid As Solvent
Authors: Watanabe Masayoshi
Published: December 2020

Ionic liquids (ILs) are now being recognized as the third group of solvents, following water and organic solvents. They are easily available and possess unique properties such as nonvolatility, high thermal stability, and designability, which make it possible to use them on demand and under harsh conditions. Our study had been focused on understanding of the unique properties of ILs and on their utilization as neoteric solvents for innovative polymeric materials and devices1,2 that can help realize a sustainable society. ILs exhibit unique solubility toward polymers;1 this opens up a new field of intelligent materials chemistry. By utilizing the unique solubility, we have proposed soft materials containing ionic liquids, which we named “ion gels”.1,2 Ion gels are a novel platform for many applications such as electrolyte membranes for batteries3 and fuel cells,4 actuators,5 gas-separation membranes,6 and electric double layer transistors.7

Especially, due to the recent surge in flexible and wearable devices, highly durable ion gels have attracted much attention. In this lecture, I will address the recent advances in the development of ion gels that have healing functions against mechanical damages. As stimuli-responsive healing strategy, light- and thermally-induced healing of ion gels are discussed mainly based on block copolymer self-assenbly changes in ILs.8-10 Then, self-healable ion gels based on supramolecular11 and dynamic bond12 chemistry are addressed. By judicious designing of polymer nanostructures in ILs and interactions between polymer chains and IL cations and anions, tough, highly stretchable, and self-healable ion gels are recently demonstrated.

References

T. Ueki, T. M. Watanabe, Macromolecules, 41, 3739 (2008).

Y. Kitazawa, K. Ueno, M. Watanabe, Chem. Record, 18, 391 (2018).

Y. Kitazawa, K. Iwata, R. Kido, S. Imaizumi, S. Tsuzuki, W. Shinoda, K. Ueno, T. Mandai, H. Kokubo, K. Dokko, M. Watanabe, Chem. Mater.,
30, 252 (2018).

S.-Y. Lee, A. Ogawa, M. Kanno, H. Nakamoto, T. Yasuda, M. Watanabe, J. Am. Chem. Soc. 132, 9764 (2010).

S. Imaizumi, H. Kokubo, M. Watanabe, Macromolecules, 45, 401 (2012).

A. Ito, T. Yasuda, T. Yoshioka, A. Yoshida, X. Li, K. Hashimoto, K. Nagai, M. Shibayama, M. Watanabe, Macromolecules, 51, 7112 (2018).

M. Matsumoto, S. Shimizu, R. Sotoike, M. Watanabe, Y. Iwasa, T. Aida, J. Am. Chem. Soc., 139, 16072 (2017).

R. Tamate, K. Hashimoto, T. Ueki, M. Watanabe, Phys. Chem. Chem. Phys., 20, 25123 (2018).

T. Ueki, R. Usui, Y. Kitazawa, T. Lodge, M. Watanabe, Macromolecules, 48, 5928 (2015).

C. Wang, K. Hashimoto, R. Tamate, H. Kokubo, M. Watanabe, Angew. Chem. Int. Ed., 57, 227 (2018).

A. Saruwatari, R. Tamate, H. Kokubo, M. Watanabe, Chem. Commun., 54, 13371 (2018).

R. Tamate, K. Hashimoto, T. Horii, X. Li, M. Shibayama, M. Watanabe, Adv. Mater., 30, 1802792 (2018).
Uranium Electrorefining in 3LiCl-2KCl Based Melts
Authors: Nikitin Dmitry , Zolotarev Daniil A. , Mukhametdyanov Artur D. , Volkovich Vladimir A. , Polovov Ilya B.
Published: December 2020

Molten halides can be effectively employed for electrorefining of refractory and radioactive metals with relatively negative reduction potentials and high melting temperatures. In the present study electrorefining of uranium was studied for developing pyrochemical reprocessing technology of metallized spent nuclear fuels. 3LiCl-2KCl molten salt was chosen as the working electrolyte. Uranium containing electrolytes were prepared by dissolving UCl3 in the solvent salt melt in an argon filled glove box to obtain various desired concentrations of uranium in the electrolyte. The working temperature in the refining experiments varied between 450 and 750 °C.

The experiments on uranium electrorefining were carried out in a stainless steel semi-industrial water-cooled electrolyser. Crude uranium metal was loaded in a specially designed molybdenum anodic basket. Glassy-carbon crucible was used to hold the melt. Molybdenum rod was employed as a cathode.

The main goal of the electrolytic refining process is obtaining high-purity uranium metal. Specific energy consumption is also very important. The results of the electrolytic refining depend on various parameters. In the present study current density, temperature, uranium concentration in the electrolyte, and specific quantity of electricity passed through the cell were selected as variables, and the current efficiently was chosen as a response factor.

Dense and compact uranium deposits were obtained under low current densities, while application of relatively high current densities led to the formation of uranium dendrites. Intermediate values of current density allowed producing more coherent deposits that could be easily scraped off the cathode. Increasing temperature led to a sharp change of the cathodic deposits morphology. The reason for this is the formation of tetragonal beta-uranium instead of the low-temperature orthorhombic alpha modification.

The values of cathodic current efficiency in the most of experiments confirmed the three-electron scheme of uranium reduction. Cathodic current density under certain conditions exceeded 95 %. The amount of salt retained in the cathodic deposit varied from 7 to 25 %, values typical for dendrite electrolytic metals.
Aluminum Ion Species Transport in Pure and Additive Modulated Deep Eutectic Solvents (DES) Electrolytes
Authors: Paterno Domenec , Suarez Sophia
Published: December 2020

The need for safe, low cost, high energy and density storage devices is ubiquitous the world over. Satisfying this need requires various energy storage and conversion applications, one of which is the aluminum ion batteries. One problem with expansion in their development and commercialization is the availability of optimized electrolytes. Recently, deep eutectic solvents (DES) have gained attention as electrolytes for energy storage devices. These solvents are similar to ionic liquids, but are generally cheaper and easier to prepare. Additionally, they are known to dissolve metal oxides which plague AIBs operation, and their solubility is dependent on the hydrogen bond donor. Because of their inherent tunability, we studied the effect of AlCl3 concentration (1:1 – 1.7:1 molar ratio), amide type (acetamide (AA), butyramide (BA), propionamide (PA)), viscosity reducing additive type and concentration, on the aluminum ion species and transport in AlCl3:amide DES electrolytes using multi-Nuclear (1H, 27Al) Magnetic Resonance (NMR) and AC Impedance Spectroscopy techniques, as a function of temperature. Below are a few noteworthy observations.

Figure 1. VFT plots of the ionic conductivity for AlCl3:AA (left) and AlCl3:PA (right) DES electrolytes.

Thirdly, the variable temperature 1H and 27Al spectra and T1 data for the pure and additives included DES electrolytes were very dependent on concentration, additive type and concentration, and species type. For example, in the 1:1 molar ratio electrolyte, the assigned AlCl2(amide)+ species had the longest T1, while the AlCl2(amide)2
+ had the shortest. Additionally, the inclusion of additives such as fluoroethylene carbonate (FEC) and propylene carbonate (PC) caused species specific increasing local ion dynamics, possibly through the reduction of bulk viscosity effects and Coulombic interactions. These results and more will be expounded upon in our presentation.

Firstly, for both AlCl3:PA and AlCl3:BA DES electrolytes, a maximum in ionic conductivity was observed at the 1.3:1 molar ratio. For AlCl3:AA DES the maximum occurred at the 1.5:1 molar ratio. Secondly, for the three amides conductivity values fell in the range of ~1 – 11 mS/cm over the temperature range of 288 – 363K. Additionally, the temperature dependence displayed curve-like behavior and were fitted using the VFT equation to reveal high levels of fragility and dynamic behaviors similarities to some pure ILs where the effective inter-conversion between the trans and cis conformations of the anion facilitated faster ion dynamics.

Figure 1
Conductivity of 1-Ethyl-3-Methylimidazolium Chloride (EMIC) and Aluminum Chloride (AlCl3) Ionic Liquids at Different Temperatures and AlCl3 Mole Fractions
Authors: Shinde Pravin , Ahmed Aninda N. , Nahian Md K. , Peng Yuxiang , Reddy Ramana G.
Published: December 2020

In this work, the conductivity (k) of Lewis acidic ionic liquid (IL) comprising a melt of organic chloride and aluminum chloride (AlCl3) with different molar ratios of organic chlorides with AlCl3 in the temperature range of 70-110 °C are reported. The ILs prepared with three imidazolium-based organic chlorides such as EMIC, BMIC, and HMIC are studied. The molar ratios of 1:1.5, 1:1.8, and 1:2.0 are selected for the study to maintain the acidity of the ILs for possible metal electrodeposition applications. The electrochemical behavior of anion species in the three ILs is studied using electrochemical impedance spectroscopy (EIS) technique and obtained the precise and fast measurement of conductivity values. The measured k values of all the ILs followed the Arrhenius law. The activation energies of conduction determined by fitting the experimental conductivity data are in good agreement with the literature. The conductivity of ILs with lower alkyl group organic chlorides decreased with the higher mole fraction of AlCl3. In contrast, the conductivity of IL having a higher alkyl group organic chloride (HMIC) increased with the increasing mole fraction of AlCl3. Based on the thermodynamic calculations, the differences in conductivities are attributed to the anion concentration, the molecular structure, cation-anion interactions, and hydrogen bonds in the ILs.
Preparation and Electrochemical Properties of Ambient Temperature Molten Chlorides Based on Quaternary Ammonium Chloride and MgCl2
Authors: Matsumoto Hajime , Akai Naoto , Oyabu Rie
Published: December 2020

The research and development of magnesium secondary batteries using magnesium anode have been attracted much attention as one of the prospective post-lithium ion batteries due to the high theoretical capacity (3830 Ah/dm3) and without no resource constraints. However, it has been quite difficult to construct the magnesium batteries because practical electrolytes for the battery has not yet been developed.

We previously reported that TFSA-based ILs were not suitable for a Mg anode even in alkali metal binary molten salt such as MgTFSA2-KTFSA, which indicated that the existence of the TFSA anion disturbed a magnesium redox on Mg electrodes. [1] On the other hand, relatively smooth magnesium redox could be observed in 1-butyl-3-methylimidazolium chloride melts containing Mg[TFSA]2. [2] However, the electrochemical window of the imidazolium melt was limited by the reduction decomposition of the imidazolium.

In this study, we reported that ambient temperature molten chlorides could be obtained by mixing a quaternary ammonium chloride and MgCl2, which did not contain the TFSA anion and also imidazolium cations. The thermal properties and also physicochemical properties were investigated. The electrochemical response of a magnesium metal in the melt were also shown to indicate the possibility as an electrolyte for a magnesium anode battery.

[1] K. Kubota, H. Matsumoto, J. Electrochem. Soc., 167 (2020) 020541.

[2] H. Matsumoto, K. Kubota, ECS Transactions, 86(14) (2018) 21.
(Invited) Relating Ion Structures and Transport Properties of Ionic Liquids
Authors: Philippi Frederik David , Clark Ryan , Koutsoukos Spyridon , Hunt Patricia A , Welton Tom
Published: December 2020

Whether used as electrolytes or solvents for synthesis both the bulk viscosity and the microscopic dynamics of ions in ionic liquids often determine the applicability of these. Hence, it is important to understand the connection between the structures of ionic liquid ions and these key properties. Features that contribute to these behaviours include ion mass, size, interactions, and flexibility and the ability of the ions to give rise to nanoscale segregation of charged and nonpolar domains.

In this work, we combine experimental and theoretical studies of a wide range of ionic liquids composed of structurally similar ions in an attempt to separate the relative contributions of these features to the transport properties of ionic liquids. We target a number of design parameters, such as the ions' central atoms (e.g., ammonium or phosphonium cations), ion substitution (e.g., alkyl chain length and degree of substitution of cations and fluorination of the anion).

In addition to the direct effects of structural changes to an individual ion, we show that the significance of these changes is often moderated by the nature of the counter ion of the ionic liquid. We also demonstrate that targeted design of functional groups based on structure-property relations can yield ionic liquids of exceptionally high fluidity.
Surface Modification of Cathode Via Precursor Coating for All-Solid-State Batteries
Authors: Lee Jun su , Park Yong Joon
Published: December 2020

Li-ion batteries (LIBs) have been used widely for mobile device, electrical vehicle (EV), and energy storage system (ESS). As the expansion of application fields, unstable safety of LIBs attributed to the flammable organic liquid electrolyte has been considered as a serious issue. All solid state batteries (ASSBs) based on nonflammable inorganic solid electrolyte could be a good solution for this issue. Until now, a lot of inorganic ionic conductors has been studied for using as solid electrolytes of ASSBs. Sulfides are promising candidates for solid electrolyte for ASSBs due to their comparable ionic conductivity to liquid electrolyte. Moreover, they can be easily assembled with electrodes due to their ductility. However, ASSBs based on sulfide electrolyte has several problems such as poor rate capability and unstable cyclic performance, which are mainly attributed to the side reaction between oxide cathodes and reactive sulfide electrolyte. Surface modification of cathode using stable materials against sulfides has been known as an effective approach for overcoming this problem. In this study, the cathode material was modified using several oxides. Specially, the coating process was started from the precursors instead of as-prepared cathodes to obtain more homogeneous coating layer. The surface modified cathodes are expected to show improved cyclic performance and rate capability due to the effect of surface modification.
3D Sn-Based Anodes for Solid State Rechargeable Batteries
Authors: Nurpeissova Arailym , Kalimuldina Gulnur , Bakenov Zhumabay
Published: December 2020

Recent rapid technological progress in various fields of industry and daily life has been driven by miniaturization of electronics. The devices for various applications such as medical devices, logic and memory circuits, and various sensors have been drastically reduced to smaller dimensions with vastly improved performance. Limited performance of batteries is one of the most critical problems to be tackled for sustainable technological advances and to allow for further development of novel and future technologies.

Lithium-ion batteries (LIBs) exhibit excellent cycle performance and high energy capacity and thus are the best choice to power miniaturized devices. However, the current architecture used in LIBs’ electrodes limits their energy and power densities. Furthermore, safety issues arising from flammable liquid electrolytes and lithium dendrite growth upon cycling still remain as the major challenges for implementation of LIBs in this area. Advanced architectures and materials are needed to design high performance LIBs with increased energy storage capacity per unit volume while maintaining a small footprint area.

A three-dimensional (3D) architecture design of the battery electrodes can remarkably enhance the energy and power densities of conventional LIBs. In this regard, we report a unique 3D architecture anode designed for all-solid battery and fabricated by electrodeposition of ultrathin Ni3Sn4 intermetallic alloy onto a commercially available nickel foam current collector from an aqueous electrolyte. The X-ray diffraction results obtained from three-dimensional electrodes indicated that the main phase of electrodeposited alloys was Ni3Sn4. The designed three-dimensional electrode demonstrated a high discharge capacity of 843,75 mAh g-1 during initial cycles and a stable cycle performance over prolonged cycling. The high surface area of the electrode and short Li+-ions diffusion paths along with suppression of volume expansion provided by the proposed 3D structure and Ni inactive matrix play a key role in improving the performance of the electrode.

Acknowledgements

This work was supported by the project 091019CRP2114 “Three-Dimensional All Solid State Rechargeable Batteries” from Nazarbayev University.

References:

[1] J.M. Tarascon, M. Armand, Issues and challenges facing rechargeable lithium batteries, Nature. 414 (2001) 359–67. https://doi.org/10.1038/35104644.

[2] M.T. McDowell, I. Ryu, S.W. Lee, C. Wang, W.D. Nix, Y. Cui, Studying the kinetics of crystalline silicon nanoparticle lithiation with in situ transmission electron microscopy, Adv. Mater. 24 (2012) 6034–6041. https://doi.org/10.1002/adma.201202744.
Proposal of Na Conductive New Solid Electrolyte and Their Physicochemical Properties and Na-S Battery Performance
Authors: Yokomaku Yuji , Hiraoka Koji , Kato Masaki , Inaba Kohei , Miyauchi Hibiki , Seki Shiro
Published: December 2020

Introduction

In general, sodium-sulfur (Na-S) battery operates by redox reaction of sodium and sulfur during charge and discharge, and this battery system contains β-Al2O3 as electrolyte, Na metal as negative electrode and S as positive electrode, respectively. It has been applied as large-scale storage system owing to their high energy density and long-life. In contrast, this system has serious problems with fire risk owing to their chemical safety of Na metal and S at high temperature (ca. 573K) as liquid state. To solve these problems, we propose low-temperature operated Na-S battery using thermally stable organic gel electrolyte with polyether-based host polymer and sulfolane (SL)-based electrolyte solution. Herein, thermal stability and ionic conductivity of proposed Na conductive gel polymer electrolyte and charge-discharge property of Na-S cell were evaluated.

Experimental

Liquid electrolytes were prepared by mixing SL and NaTFSA using shading bottle in Ar-filled glove box. The molar ratio was changed to xSL:1NaTFSA (x=2,3,4,5 and 6, respectively). These liquid electrolytes and polyether-based macromonomer (P(EO)/(PO), polymer) were mixed with changing weight ratio as followed formula; y liquid electrolyte: (10-y)polymer (y=7 and 8). After Added DMPA as photo-initiator, solid gel polymer electrolytes were fabricated by photo-polymerization by UV irradiation. Prepared samples were expressed as (xSL)yEl+(10-y)Po. Thermophysical properties of fabricated gel polymer electrolytes were evaluated by thermogravimetric analysis (TG, Thermo plus EVO2, Rigaku) and differential scanning calorimeter analysis (DSC, Thermo plus EVO2, Rigaku). In addition, ionic conductivities were measured by electrochemical impedance method. The reversibility of Na-S batteries was evaluated by charge and discharge measurements at 333 K.

Results and discussion

The prepared electrolytes showed high flexibility at room temperature. Therefore, P(EO/PO) polymer matrix might be playing a role as framework phase to SL-based liquid electrolytes. Figure 1 shows the temperature dependence of the ionic conductivity of the gel electrolyte for each composition. The Ionic conductivity increases with composition of SL owing to their viscosity decreasing of SL electrolytes. Also, it was notable that high ionic conductivity observed in low SL composition at low temperature. Figure 2 shows charge and discharge profiles of prepared Na-S cells at 333 K. Sufficient charge and discharge operations at relatively low temperature (333 K) and exhibited a high capacity of approximately 350 mAh/g.

Figure 1
Enhanced Air-Stability of Argyrodite Solid Electrolyte By Introducing Zeolite Additive As H2s Scavenger
Authors: Cho Woosuk , Kim Won-Joo , Lee Dong-geon , Kim KyungSu , Park Kern-Ho , Jeong Goojin , Yu Ji-Sang
Published: December 2020

All-solid-state batteries (ASB) have received great attention as a next generation power source due to its safe characteristics with non-flammable solid electrolyte. Whole battery reactions are occurred in solid-state Li+ migration in ASB, therefore the well-contacted interfacial area is critical for battery performance. Especially for ASB with high energy density, casting process is suitable to form a large sized sheet of electrode and electrolyte. When electrode and electrolyte sheets are fabricated by conventional cold pressing, sulfide solid electrolyte is favorable to form a contact area effectively due to its elastic powder character compared to oxide. However, sulfide solid electrolyte is chemically unstable with humidity in air. It easily generates H2S gas that is toxic and hazardous. Residual Li2S and bridge sulfur in structure are known as main cause of H2S generation. The ionic conductivity is also decreased by the decomposition of solid electrolyte by undesirable H2S generation. In this study, zeolite were used as additive for H2S scavenger. 5 wt% of zeolite additive was mixed with argyrodite-type Li6PS5Cl, then exposured in moisture air (Rh 50%). The amount of H2S gas generation was greatly reduced by introducing zeolite additive. Decease of ionic conductivity after air exposure is also suppressed by zeloite additive. It also affect to cell performance such as specific capacity and cycle performance. On the basis of these results, adding H2S scavenger is proposed as a visible method for enhancement of air-stability of sulfide solid electrolyte. The detailed results will be discussed at the meeting.
Understanding Kinetics of Complex Interfaces in Solid-State Batteries from Multiscale Simulations
Authors: Wood Brandon C. , Heo Tae Wook , Wan Liwen , Dive Aniruddha Mukund , Jana Aniruddha , Shi Rongpei , Kang ShinYoung , Kweon Kyoung , Grieder Andrew , Adelstein Nicole
Published: December 2020

Developing viable solid-state batteries requires understanding the various chemical and physical processes that occur at homogeneous and heterogeneous solid-solid interfaces. Examples include internal grain boundaries, interphases, and electrode-electrolyte interfaces, each of which can play a key role in determining transport and cycling stability. To explore these impacts in detail, our team has been applying simulations from the atomic scale to the mesoscale, considering the structure, chemistry, and dynamics of the solid-state interfaces. We will provide an overview of these activities as applied to the garnet Li7-xLa3Zr2O12 (LLZO) solid electrolyte system. First, we will show how mesoscale phase-field models can be combined with atomistic simulations of grains and grain boundary regions to predict and assess the transport properties of interface-dominated systems. We apply this framework to determine the operating conditions and microstructural considerations for which grain boundaries appreciably affect diffusion mechanisms and pathways in LLZO. Second, we will show how ab initio simulations are applied to isolate local chemical motifs that act as precursors to interphase formation at the LLZO-cathode interface. Evidence of interdiffusion and structural reorganization at the interface provides clues into possible degradation mechanisms, in addition to impacting interfacial impedance. Overall, the simulation results highlight the importance of considering interfaces in realistic materials descriptions of solid-state batteries, while simultaneously highlighting the possible tunability of microstructure at multiple scales to impact performance.

This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.
Improving Cell Resistance and Cycle Life with Solvate/Thiophosphate Hybrid Electrolytes in Lithium Metal and Lithium Sulfur Batteries
Authors: Gewirth Andrew A. , Philip Maria , Shin Minjeong , Madsen Kenneth
Published: December 2020

Solid electrolytes (SEs) have become a practical option for lithium ion and lithium metal batteries due to their improved safety over commercially available ionic liquids. The most promising of the SEs are the thiophosphates whose excellent ionic conductivities at room temperature are comparable to those of the commercially-utilized ionic liquids. Hybrid solid-liquid electrolytes exhibit higher ionic conductivities than their bare solid electrolyte counterparts due to decreased grain boundary resistance, enhanced interfacial contact with electrodes, and decreased degradation at the interface.

In this study, we evaluate a series of hybrid electrolytes made from a ‘solvate’ electrolyte in both Li-Li symmetric cells and in a full cell with a Li2S cathode relative to their bare Li/SE/Li counterparts. Interestingly, hybrid electrolytes made by combining HFE-modified solvates and SE exhibit all the benefits of the interlayer modified SEs, without the necessity of pellet manufacture. The solvate-integrated cathode layer is additionally beneficial for achieving high active material utilization, maintaining intimate interfacial contact, and providing buffer space for volume contraction and expansion. X-ray tomography measurements show the presence of a buffer layer results in substantially less crack formation. The hybrid Li2S cell exhibited superior cycling performance compared to the solid-state cells in terms of Li2S loading, Li2S utilization, and cycling stability. Finally, we discuss the use of hybrid electrolytes to enable other cathode chemistries.
In Situ characterization of Reactive Lithium Metal Interfaces in Solid-State Batteries
Authors: Lewis John A , Cortes Francisco Javier Quintero , Liu Eugene , Tippens Jared , McDowell Matthew T
Published: December 2020

Solid-state lithium metal batteries have garnered significant interest in recent years due to the potential for solid-state electrolytes (SSEs) to enable a lithium metal anode by suppressing dendrite growth and eliminating hazardous liquid electrolytes. However, the development of solid-state lithium metal batteries has been limited by numerous challenges that exist at the interface between lithium and SSEs. These issues typically manifest as lithium metal penetration through the electrolyte, void formation at the interface, or interfacial decomposition to form an interphase. Here, we characterize the Li/SSE interfaces between reactive oxide and sulfide SSEs in situ and operando during the cycling of symmetric cells. Using a modified cell geometry with the oxide SSE Li1.4Al0.4Ge1.6(PO4)3 (LAGP), we are able to monitor interphase growth and crack propagation throughout cycling with an optical microscope. Cycling at higher current densities reveals significantly more interphase growth in LAGP, accelerating crack growth and cell failure. Operando synchrotron X-ray tomography of symmetric cells using the sulfide SSE Li10SnP2S12 reveals the dynamic processes of both interphase and void formation at the interface. Segmentation of voids and interphase enables us to quantify the volume of these phases and relate these parameters to changes in electrochemistry. These results demonstrate the importance of interfacial stability from both a chemical and mechanical standpoint.
Mesoscale Elucidation of Electrodeposition in All-Solid-State Lithium Batteries
Authors: Vishnugopi Bairav Sabarish , Verma Ankit , Kawakami Hiroki , Wada Hiroyuki , Hirowatari Anna , Ikeda Nobuhisa , Mizuno Yoshifumi , Kotaka Toshikazu , Aotani Koichiro , Tabuchi Yuichiro , Mukherjee Partha P.
Published: December 2020

Lithium metal anodes, owing to their theoretical promise have been considered decisive towards the development of next-generation battery systems with higher power and energy densities. Compared to the liquid counterparts, solid electrolytes proffer enhanced safety and dendrite suppression features due to the non-flammability and mechanical stiffness. However, the electrodeposition dynamics at a solid-solid interface is quite intricate, involving coupled transport, mechanical and kinetic processes, which are closely related to the interfacial heterogeneities. Furthermore, the mechanical properties of the solid electrolyte, lithium metal and externally applied pressure influence the mechano-electrochemical interaction and hence the interfacial stability. In this work, a mechanistic understanding of the mesoscale underpinnings in the electrodeposition stability at solid-solid interfaces for all-solid-state lithium batteries will be presented.
Highly Ordered Adlayer Formation of Water-Insoluble Nanographenes on Gold Using "Molecular Container"
Authors: Yoshimoto Soichiro , Origuchi Sakura , Sasano Senri , Hashiguchi Shunta , Fukaminato Tsuyoshi , Yoshizawa Michito
Published: December 2020

Carbon materials such as graphene have been extensively studied for their application in electronic devices,electrocatalysis, and sensors. In contrast, polycyclic aromatic hydrocarbons (PAHs), the so-called nanographenes, are excellent materials for the creation of two-dimensional (2D) nanosheets.[1] The formation of adlayers on electrode surfaces is challenging because PAHs without peripheral substituents are used as 2D molecular templates and applications in conductance enhancement and organic field-effect transistors.[2] However, large PAHs tend to exhibit poor or no solubilities in organic solvents and water.

To overcome this issue, in this study, we employed water-soluble micellar capsules consisting of V-shaped amphiphilic molecules. Characteristic electrochemical behaviors were observed in 0.1 M H2SO4 in the presence of the water-soluble capsules containing PAHs such as dicoronylene. Furthermore, under these conditions, PAHs were released from the capsules, resulting in the formation of a 2D adlayer of PAHs at the electrochemical interface. Finally, using electrochemical scanning tunneling microscopy (EC-STM), we demonstrate that our molecular containers based on the water-soluble molecular capsules allow the facile preparation of 2D PAH adlayers in addition to structurally controlling nanostructure formation on Au surfaces.In particular, dicoronylene molecules formed a highly ordered adlayer with c(4 x 8√3)rect adlattice.[3]

References:

[1] J. Wu, W. Pisula, K. Müllen, Chem. Rev.
2007, 107, 718.

[2] L. Zhang, Y. Cao, N. S. Colella, Y. Liang, J.-L. Brédas, K. N. Houk, A. L. Briseno, Acc. Chem. Res.
2015, 48, 500.

[3] S. Origuchi, M. Kishimoto, M. Yoshizawa, S. Yoshimoto, Angew. Chem., Int. Ed.
2018, 57, 15481.
Exploiting Buoyancy Driven Flow As an Alternative Flow Battery Design
Authors: Mohr Robert , Steingart Daniel A.
Published: December 2020

It can be shown that the density gradients formed during operation of many traditional flow battery chemistries give rise to substantial natural convection. This convection tends to dominate transport within a cell with no forced flow. Using the zinc-bromine chemsitry as an example we show how this principle can be used to design a minimal architecture cell needing no pumps, membranes, or complexing agents. Density gradients are used to keep active materials separated while buoyancy driven flow is used to increase the transport of solution phase reactants during discharge. This design can maintain reasonably high efficiencies and energy density (90% CE, >45 Wh/L) while significantly cutting the balance of plant costs compared to traditional zinc-bromine flow batteries.
(Invited) Power-to-X: Evaluating Commodities As Long-Duration Energy Storage
Authors: Ciez Rebecca
Published: December 2020

Achieving a net-zero emissions economy will require substantial changes to our electricity systems and to the ways that we manufacture the raw materials that become the products we use every day. These zero-carbon electricity systems will also require new, low-cost energy storage solutions to manage both daily and seasonal variability of renewable electricity resources. At the same time, we must also take steps to decarbonize resource-intensive industrial processes. While batteries are well-positioned to provide intra-daily load shifting, and intermediate fuel storage in the form of hydrogen or ammonia is possible, we have not fully investigated the role that industrial commodities, including metals, can play in a decarbonized energy system. This talk will examine the emissions benefits of converting metals refining processes to use renewable sources of electricity, and the costs associated with using the produced materials as a source for infrequent, but extreme demands for stored energy. Beyond capital costs, the analysis also considers factors like changes in labor demand necessary for manufacturing processes to adapt to renewable sources of electricity, and serve as backup reserves of stored energy, and the policy challenges of implementing embodied energy storage systems.
(Invited) Comparative Reliability Testing of Li-Ion Battery Chemistries Under Grid Services
Authors: Choi Daiwon , Crawford Alasdair J. , Viswanathan Vish , Shamim Nimat , Huang Qian , Thomsen Ed , Reed David , Sprenkle Vincent
Published: December 2020

Electrochemical energy storages are playing a vital role in stabilizing the electrical grid as more solar and wind generation are integrated into the grid infrastructure. However, reliability and performance of various stationary energy storage systems currently deployed have not been clearly evaluated and compared. In this presentation, reliability of different Li-ion battery chemistries under standardized grid duty cycles will be presented. The lifecycle derived from capacity, round trip efficiency (RTE), resistance, charge/discharge energy and total utilized energy of the battery chemistries will be compared. Furthermore, effect of aging, frequency regulation (FR), peak shaving (PS) and electric vehicle (EV) drive cycles on degradation mechanisms of different battery chemistries will be discussed.
A Novel Approach for Understanding Heterogeneous Lithium-Ion Battery Aging Using Phase-Field Model
Authors: Atalay Selcuk , Gulsoy Begum
Published: December 2020

Aging due to capacity fade is a major cause of concern in the fast growing lithium-ion battery (LIB) industry. In particular, the evolution of Solid Electrolyte Interface (SEI) have been on the focus of battery scientist as one of the primary aging mechanism affecting the cycle life of the battery. According to the recent experimental studies, the formation of SEI possesses a heterogeneous morphology and it is attributed to the (i) anisotropic ionic mobility in the crystal and (ii) surface reactions governing the flux of ions across the electrode/electrolyte interface, depending on the local free energy difference (1, 2). In contrast to most previous study which utilise rough simplification on modelling of SEI growth, we employed a novel aging formulation that captures the heterogeneous multi-layered SEI morphology by including Cahn-Hilliard interstitial diffusion modelling approach coupled with Nernst-Planck and Butler-Volmer equations for mass transport and surface chemistry, respectively. Since the Cahn-Hilliard is able to captures the anisotropic surface intercalation reactions with depending the local free energy difference of active material, our numerical theory shows promising results for better explaining the cause of the heterogeneous SEI growths on active material surfaces than the classical diffusion-limited model.

W. Huang, P. M. Attia, H. Wang, S. E. Renfrew, N. Jin, S. Das, Z. Zhang, D. T. Boyle, Y. Li and M. Z. Bazant, Nano letters, 19, 5140 (2019).

P. Guan, L. Liu and X. Lin, Journal of The Electrochemical Society, 162, A1798 (2015).

Figure 1
Stable Photoelectrochemical Hydrogen Evolution for 1000 Hours at 14% Efficiency in a Monolithic Device
Authors: Kistler Tobias , Um Min Young , Danilovic Nemanja , Agbo Peter
Published: December 2020

The development of a fully-integrated, photoelectrochemical (PEC) device coupling water oxidation to hydrogen evolution using a III-V triple-junction photovoltaic (PV) embedded in a Nafion membrane is reported. This architecture is genuinely monolithic, with wireless catalyst integration being achieved via compression of metal sputter-coated, carbon electrodes against the front and back PV contacts. The resulting MEA-type, sandwich structure minimizes the path length for proton conduction through the membrane ionomer, while simultaneously preventing PV light attenuation by the catalyst layer, a common issue for monolithic PEC structures. While the wireless nature of monolithic PEC devices typically prevents the measurement of current flow and faradaic efficiencies, we circumvent this complication through the placement of an electrical shunt between the PV and the cathode catalyst layer, rerouting charge generated at the PV through a potentiostat prior to cathodic proton reduction. Using this device architecture, we demonstrate significant enhancements in device stability and longevity, by transitioning from a liquid-water to water-vapor anode. Our use of a gas-fed anode enables 1000 hours of cumulative device operation at a peak solar-to-hydrogen efficiency of 14%, during simulated, solar illumination at 1 sun and outdoor, diurnal cycling. Vapor-fed water oxidation is shown to reduce drops in device performance by mitigating the corrosion effects that are commonly associated with full-aqueous immersion of the electrochemical and photovoltaic elements in PEC devices. Causes for observed fluctuations in device performance are determined through the collection of real-time, current-voltage data, paired with an analytical method, permitting the deconvolution of PV- and catalyst-driven performance losses.

Figure 1
(Invited) Coating-Stabilized Particulate Photocatalysts for Solar H2 Production
Authors: Hu Shu
Published: December 2020

Particulate photocatalysts that are suspended in water or sprayed onto a panel promise solar-to-fuel energy conversion at scale. The fabrication processes for these photocatalysts to achieve efficient energy conversion should be simpler than panel-based photoelectrodes. However, the design principles for reaching their performance limit are still elusive. Herein, our group uses stabilization coatings to enable an entire class of otherwise unstable particulate semiconductors for coevolution photocatalysis. CdS particles that are sprayed onto a panel and stabilized by an ALD coating produce H2 at a record rate of 48.5 mmol∙h-1∙g-1 or 2.5 mL H2∙h-1∙cm-2 under 1-sun solar illumination in ambient air. We systematically advance towards the solar-to-fuel efficiency limit of photocatalysts. Moreover, we demonstrate a redox-mediated particulate reactor that produces H2 and O2 gases at two separated compartments. The O2-evolution processes are separated spatially and temporally from photocatalytic H2 production, which is safe. We will discuss new design principles based on the holistic understanding of the photophysical, electrocatalytic, and transport processes that are coupled at the nanoscale.

Figure 1
(Invited) Solar Photoelectrochemical Fuel Generation Using Electrochemically Fabricated Nanomaterials
Authors: Varghese Oomman K
Published: December 2020

Replacing fossil fuels with chemical fuels generated from carbon free resources or via carbon dioxide recycling using solar energy has been widely recognized as a potential strategy for controlling the accumulation of carbon dioxide in the atmosphere and bringing sustainable developments in the energy sector. Among the solar fuel production technologies evolved in recent decades, water splitting and carbon dioxide reduction performed using solar photoelectrochemical (PEC) processes are highly promising. The PEC processes utilize photocatalytic properties of semiconducting materials for the conversion of energy in the ultraviolet to near infrared region of the solar spectrum to chemical energy. Since the development of electrochemical methods to fabricate highly ordered nanostructured semiconductors, there has been a surge of activity in involving these materials for PEC fuel generation. Electrochemical processes such as anodic oxidation have been demonstrated to yield stable materials with superior light harvesting and utilization properties. An area of substantial research interest in recent years is the fabrication of new materials with improved PEC performance using a combination of techniques including electrochemical. Such hybrid techniques have introduced several low dimensional materials and heterostructures with unique properties. This presentation is aimed at discussing the recent advances in PEC fuel generation processes brought by the nanomaterials and heterostructures fabricated using electrochemical and hybrid techniques.