bluuebunny/crossref_metadata_2025 huggingface dataset:
Toward All-Ceramic Solid State Lithium Battery: Hot-Pressing Nasicon Electrolyte
Authors: Paolella Andrea , Savoie Sylvio , Girard Gabriel , Guerfi Abdelbast , Zaghib Karim
Published: December 2020

In this presentation we show the influence of pressure during the hot sintering stage on the ionic conductivity of the lithium super ionic conductor Li1.5Al0.5Ge1.5(PO4)3 (LAGP) as electrolyte for solid state lithium battery 1. A new method is developed to obtain high ionic conductivities at only 650 °C by applying pressure (56 MPa) instead of standard 850-900°C. Considering the possible decomposition reactions when cathode materials are annealed at high temperature (typically ≥700 °C), the use of high pressure at 650 °C can significantly limit the formation of side-products. In this presentation we show the criteria required to optimize the pressure and temperature parameters for enhancing the total ionic conductivity. Finally, this study reports an all solid-state battery based on a LiFePO4 olivine cathode prepared at 650 °C showing very good Li-intercalation/deintercalation performance. Good ionic interfacial contact is achieved without using polymer and liquid electrolyte at the positive electrode.

1 Paolella et al. Advanced Materials Interfaces, 2020, Just Accepted Manuscript DOI: 10.1002/admi.202000164

Figure 1
Elucidating Interfacial Stability Issues Via Crystallographically Controlled Interface of a Dense Bulk Cathode and Solid Electrolyte
Authors: Zahiri Beniamin , Patra Arghya , Braun Paul V , Kiggins Chadd , Cook John B.
Published: December 2020

Interface stability plays a crucial role in realization of solid state batteries (SSBs) as safer, higher energy density alternatives to conventional Li ion batteries. Recent developments in inorganic halide solid electrolytes appear to be providing a path to stable interfaces between the solid electrolyte and higher voltage cathodes, although understandings of this interface, and how this interface controls cell performance have been quite limited. Here, using Li3YCl6 and Li3InCl6 as example halide solid electrolytes and thick dense conductive additive and binder-free LiCoO2 cathodes we show that the interface dominates cell performance. Using this halide solid electrolyte-solid cathode system, we demonstrate for the first time the role of cathode crystallography on interfacial phenomena. Our findings highlight that minimizing the interfacial area, rather than its expansion as with a conventional composite cathode-solid electrolyte mixture is key to both understanding the nature of interface instabilities and optimizing cell performance.
Superior Peak to Valley Current Ratio of the InAs/Gasb Core-Shell Nanowires for Tunnel Diode Application
Authors: Hsu Che-Wei , Luc Quang Ho , Ko hua Lun , Huang Ping , Wu Jing Yuan , Tran Nhan Ai , Chang Edward Yi
Published: December 2020

Raising transistors density led by scaling is responsible for the increase of the power consumption. Consequently, the supply voltage scaling is a strong issue in recent years. Tunnel diode is considered as one of the potential candidate for low power applications. In this respect, the broken-gap InAs/GaSb heterostructure which has narrow bandgap and small effective mass that increase interband tunneling probability to use to fabricate the core-shell nanowires for low power tunnel diode application. Peak to valley current ratio (PVCR) of negative differential resistance is a property which occurs in tunnel diode to determine the amplification of an AC signal ability. We demonstrate an intensive negative differential resistance phenomenon and PVCR in InAs/GaSb core-shell nanowires device. The tunnel diode characteristics display a higher peak to valley current ratio of 8.69 at VDD= 0.32 V. Among all published literature, our result show a record high PVCR to the author’s best knowledges. InAs/GaSb core-shell nanowires are promising candidate for low power high switching speed application.
A Molecular Approach to Control the Morphology and Properties for the Development of Highly Conductive and Stable Anion Exchange Membranes
Authors: Al Munsur Abu Zafar , Kim Tae-Hyun
Published: December 2020

Anion exchange membrane fuel cells (AEMFCs) have drawn growing interests in the past decade.The inexpensive non-platinum group metal (non-PGM) catalyst and faster oxygen reduction reactions (ORRs) kinetic at high pH are the potential driving force to develop AEM materials.Despite numerous studies, molecular design rules have not yet been fully elucidated for the development of highly conductive and alkaline stable AEMs. Polymer materials that can produce tunable nanoscale and well-developed micro-phase separated morphology hold great promises as highly conductive and alkaline stable AEMs.Understanding the relationship between the structure and electrical/physicochemical properties of the corresponding AEMs are critical to the rational design and development of AEMs.

We report herein a systematic approach to develop highly conductive and alkaline stable anion exchange membranes based on the non-(aryl ether) polymer backbone grafted with the pendant quaternary ammonium as an ion-conducting head group and the alkyl chain as a hydrophobic spacer in different ways. The effects of structure on the properties of the corresponding AEMs such as morphology, ion conductivity, physicochemical properties, and fuel cell properties will be investigated in detail.
Oxygen Reduction Reaction Activity of Nanocolumnar Pt:Ni Alloy Thin Films By High Pressure Sputtering
Authors: Ergul Busra , Yang Zhiwei , Basurrah Assem Omar , Perry Mike , Reeves Kimberly S. , Cullen David A. , Karabacak Tansel
Published: December 2020

Self-supported nanocolumnar Pt-Ni alloy thin films (TFs) with different Pt:Ni compositions and Pt mass loadings were fabricated by high pressure sputtering (HIPS) on a microporous layer (MPL)-like surface composed of carbon particles in order to mimic the catalyst-coated gas diffusion layer (gas diffusion electrode) in a membrane electrode assembly and investigated as oxygen reduction reaction (ORR) electrocatalysts for polymer electrolyte membrane fuel cells. HIPS is a simple physical vapor deposition method that is scalable and easily applicable to industrial sputter deposition systems. At high working gas pressures, columnar and less-dense structures are formed because of angular distribution of sputtered atoms that leads to a shadowing effect. Cauliflower-like microstructures were observed from scanning electron microscopy imaging. X-ray diffraction and quartz crystal microbalance analysis revealed that by simply changing the relative deposition power between Pt and Ni source, different Pt:Ni compositions can be achieved. Benchtop cyclic voltammetry and rotating disk electrode measurements were performed for electrochemical characterization of the Pt:Ni-TF/MPL-like-layer/glassy-carbon samples in an aqueous perchloric acid electrolyte. The electrochemically active surface area (ECSA) ranged between 22-42 m2/g for varying Pt:Ni compositions. Lower Pt mass loadings showed a higher ECSA likely due to smaller nanocauliflower diameters, while the ORR activity of all compositions increased as the Pt mass loading is increased. The catalytic performance of the Pt:Ni-TFs increased in the order of 3:1 < 1:1 < 1:3 with the 1:3 films exhibiting a specific activity of 1781 µA/cm2 and mass activity of 0.66 A/mg, indicating efficient catalyst utilization. The Pt:Ni-TFs were found to exhibit higher ORR activity than traditional high surface area carbon supported Pt nanoparticles, elemental Pt nanorods, and Pt-Ni nanorods.
Sulfonated Poly(Ether Sulfone)-Coated and-Blended Nafion Membranes with Enhanced Performance and Reduced Hydrogen Permeability
Authors: Goo BonHyuk , Kim Tae-Hyun
Published: December 2020

In the current work, thin sulfonated poly(arylene ether sulfone) (sPES)-coated Nafion membranes (The sPES-c-Nafions) are developed, for the first time, by simply spin-coating the sPES solution onto a Nafion membrane, and the results are compared with the sPES-blended Nafion counterparts. The sPES-c1-Nafion demonstrates a very high proton conductivity of 223.3 mS cm-
1 (80 °C) and very low hydrogen permeability, a 41% reduction compared to that of Nafion-212, together with improved mechanical and dimensional stabilities compared to Nafion-212. This newly developed membrane also shows excellent cell performance (i.e., with a current density of 1.56 A cm-
2 and a peak power density of 1.20 W cm-
2 at 0.6 V potential in the actual operating conditions of PEMFCs)
Low Temperature Synthesis of Halide Phosphors Using Novel Water-Assisted Solid-State Reaction Method
Authors: Toda Kenji
Published: December 2020

In recent years, nano-phosphor materials have attracted much attention due to their signiﬁcant potential for high-performance micro-LED displays and solid state lighting devices. In addition, nano-phosphors are considered to be promising candidates for spectral-converters to enhance the energy-conversion efﬁciency of silicon solar cells. Synthesis of nano-phosphors can be categorized in two ways namely, chemical and physical methods. Various methods such as the sol-gel, hydro-thermal, or the polymerized complex methods are usually used to synthesize nano-phosphor materials. However, these methods require expensive and special experimental equipment, raw materials, or solvents.

In this study, we synthesized nano-sized halide phosphors using a novel water-assisted solid-state reaction (WASSR) method. This novel soft chemical synthesis method is very simple and can synthesize nano-particle materials just by storing or mixing raw materials added a small amount (typically 10wt%) of water in a reactor at low temperature below 500 K. Typical particle sizes (under 100 nm) of the samples prepared by the WASSR method were smaller than that (2 - 10 micrometer size) of the sample prepared by the conventional solid-state reaction method.

For example, a stoichiometric mixture of CsCl, CaCl2 and EuCl3 hydrate was mixed for the WASSR synthesis of CsCaCl3:Eu2+ phosphor. Then, a small amount (2 wt%) of water was added to the mixture and mixed using mortar for 1 min to synthesize a single phase of CsCaCl3:Eu3+. For the reduction of Eu3+ ion, 6 wt % of hydrazine monohydrate was added to the CsCaCl3:Eu3+ and heated in the closed reactor for 12 h at 493 K. The XRD pattern of the products are in good agreement with that of single phase CsCaCl3. The SEM image and the photoluminescence spectra of CsCaCl3:Eu2+ is shown in Figure. CsCa0.09Eu0.01Cl3 shows strong blue emission under the excitation of UV light. Our proposed low cost and low-temperature synthesis technique are promising for an industrial application for phosphor materials synthesis processing.

Acknowledgment

This research was financially supported by the Ministry of Trade, Industry and Energy(MOTIE) and Korea Institute for Advancement of Technology(KIAT) through the International Cooperative R&D program (P0006844_Development of color conversion nanocrystal luminescence materials for next generation display).

References

[1] T. Kaneko, S. W. Kim, A. Toda, K. Uematsu, T. Ishigaki, K. Toda, M. Sato, J. Koide, M. Toda, Y. Kudo, T. Masaki, and D. H. Yoon, Sci. Adv. Mater., 7, 1502 (2015).

[2] S-W. Kim, T. Hasegawa, M. Watanabe, M. Muto, T. Terashima, Y. Abe, T. Kaneko, A. Toda, T. Ishigaki, K. Uematsu, K. Toda, M. Sato, E. Kawakami, J. Koide, M. Toda, Y. Kudo, T. Masaki and D. H. Yoon, Appl. Spect. Rev., 52, 1 (2017).

Figure 1
Electrochemically Stimulated Molecule Releaseassociated with Interfacial pH Changes
Authors: Bellare Madhura , Kadambar Vasantha , Bollella Paolo , Katz Evgeny , Melman Artem
Published: December 2020

Stimuli responsive materials are extremely important in many applications in biomedical and biotechnological field.1 Over past several decades, a large number of materials/systems which respond to the various activating/deactivating signals have been proposed and developed. External stimuli controlled release of therapeutic agents is one among such systems. In this field a large variety of stimuli such as pH, temperature, light, magnetic field and many more have been exploited to achieve signal stimulated release of drugs/biomolecules. Electrochemically triggered release of (bio)molecules is gaining attention due to the simplicity and easy integration of those systems with sophisticated electronic devices. These methods take advantage of some common phenomenon such as formation/cleavage of redox bonds (for example; disulfide linkages), electrostatic association/dissociation2,3, and entrapping/releasing the (bio)molecules from the (bio)polymer gels for achieving immobilization and electrochemically stimulated release. While these methods are powerful, they have their own limitations (for example, reduction of disulfide bonds is significantly complicated in presence of other redox species). Hence to design an universal approach for electrochemically triggered release of (bio)molecules, we investigated the development of a hydrolysable linker at mild basic (pH 8-10) conditions. Herein we report a new linker with a hydrolysable phenolic ester bond at basic pH (~8-10) for electrode modification. Basic pH locally produced at the electrode surface upon electrochemical reduction of oxygen resulted in the hydrolytic cleavage of the phenolic ester bond and release of the immobilized fluorescent dye used as a model compound4.
Electrochemical Control of Neuroblastoma Differentiation Based on Nanostructured Biohybrid Material
Authors: Lim Joungpyo , Yoon Jinho , Choi Jeong-Woo
Published: December 2020

Because of its high applicability to regenerative medicine and stem-cell therapy, accurate control of the neural differentiation has attracted lots of attention in the neurobiological field. For this reason, the introduction of nanoparticles or nanopatterned electrode for the induction of accurate neural differentiation has been reported by various researchers. However, these materials still have limitations such as cytotoxicity effects caused by nanoparticles and low specificity and efficiency of differentiation. Therefore, it is essential to develop a new method of inducing neural differentiation with high biocompatibility and specificity to solve the above-mentioned shortcomings. In this study, for the first time, the nanostructured biohybrid material composed of recombinant azurin (Azu), DNA, and gold nanoparticle (AuNP) for the neural differentiation with high biocompatibility and specificity was developed. Due to the introduction of biomaterials such as Azu and DNA, the nanostructured biohybrid material showed high biocompatibility. Furthermore, electrically controllable complex with the differentiation inducible agent allowed by introduced AuNP connected to the nanostructured biohybrid material without the chemical linker. The result showed that the neural differentiation was successfully conducted by the release of the differentiation inducible agent from an electrically controllable complex with electrochemical control. Moreover, it was possible to spatiotemporal control of the neural differentiation over a long period by adjusting the time and location of applying electrical stimulation. In conclusion, the developed nanostructured biohybrid material can be applied as a novel platform that can effectively differentiate stem cells into the desired type of differentiated cells for regenerative medicine and stem cell therapy.
Neuronal Tau Protein Film Stability on Gold Surface: Electrochemical Impedance Spectroscopy of Partial and Complete Surfaces
Authors: Wallace William , Martic Sanela
Published: December 2020

Tau is a neuronal protein responsible for microtubule formation [1]. It is also the pathological protein active in the Alzheimer’s Disease (AD) pathway. When Tau begins to aggregate as a result of misfolding, the neuronal cells die due to the lack of microtubule formation and can take on prion-like properties [2]. Therefore, detection of aggregated Tau can serve as a powerful tool in the early diagnosis of AD and dementia related diseases. As has been previously demonstrated, Tau 441 can be detected with an electrochemical immunoassay based on the electrochemical impedance spectroscopy (EIS) by using gold electrode [3]. The EIS was also used to monitor interactions between Tau protein and Heparin [4]. Due to the sensitive nature of protein molecules, buffers of physiological pH need to be employed to maintain native protein structure. However, not all buffer solutions are appropriately suited for surface studies. Herein, we describe use of EIS to monitor and detect surface stability of Tau protein films on gold electrode in two common buffers: MES buffer and Phosphate Buffer (PB). Additionally, the stability of partial and complete surfaces was also monitored. The partial surface was completed by backfilling with a solution of bovine serum albumin (BSA) and the complete surface was backfilled using 1-butylamine and hexanethiol. After modifying the surface of the electrode with activated lipoic acid and Tau, a series of further incubation steps were performed to test surface stability under various conditions. The EIS was measured as a function of Tau or Heparin concentrations, and incubation time and temperature. The control experiments included, Tau-free surface, Heparin-free solution, and buffer solutions in order to minimize non-specific interactions. The stability of the surfaces was measured as a signal change in EIS after incubations and it was discovered that certain buffered solutions and partial surfaces induced large changes in tau protein films on surfaces.

References

[1] M.D. Weingarten, A.H. Lockwood, S. Hwo, M.W. Kirschner, A Protein Factor Essential for Microtubule Assembly, Natl. Acad Sci. 72 (1975) 1858–1862.

[2] F. Clavaguera, J. Hench, M. Goedert, M. Tolnay, Prion-like transmission and spreading of tau pathology, Neuropathol. Appl. Neurobiol. 41 (2015) 47–58.

[3] N. Carlin, S. Martic-Milne, Anti-tau antibodies based electrochemical sensor for detection of tau protein biomarkers, J. Electrochem. Soc. 165 (2018) G3018–G3025.

[4] H. Trzeciakiewicz, J. Esteves-Villanueva, R. Soudy, K. Kaur, S. Martic-Milne, Electrochemical characterization of protein adsorption onto YNGRT-Au and VLGXE-Au surfaces, Sensors (Switzerland). 15 (2015) 19429–19442.
Electrochemical Characterization of Carboplatin at Unmodified Platinum Electrodes and Its Application to Drug Uptake Studies in Ovarian Cancer Cells
Authors: Luu Huy Tran Le , Nachtigal Mark W. , Kuss Sabine
Published: December 2020

Epithelial ovarian cancer (EOC) has the highest mortality rate among gynecological cancers and affects patients on all continents. Primary treatments involve surgery and the administration of chemotherapeutics, such as carboplatin, which is listed by the World Health Organization as an essential medication for the treatment of human cancers. Unfortunately, due to high rates of drug resistance of EOC towards carboplatin, cancer relapse rates are devastating, and the mechanisms of chemoresistance to carboplatin have not been adequately identified. Consequently, there is a dire need for innovative strategies that are able to detect carboplatin resistance in cancer and to further our understanding of the fundamental nature of chemoresistance towards carboplatin.

The presented work describes the thorough electrochemical characterization of carboplatin. We quantify the uptake of carboplatin by ovarian cancer cells by electrochemistry to better understand mechanisms of carboplatin chemoresistance. Results emerging from this research will be important for future medical research developing novel agents to combat chemoresistance.
Preparation and Mnuplation of Silver Nanostructure with Plasmon Activity By a Simple Method
Authors: Hyono Atsushi , Yoshitani Riu , Takase Mai , Suzuki Keita , Ito Fuminori , Chiba Makoto
Published: December 2020

Introduction: One of metal fine particles’ applications is Surface Enhanced Raman Scattering; SERS) with their surface plasmon resonance. It is usually performed on the substrates which have gold or silver clusters on their surface. It can be enhanced at the gap between two clusters much more than at the surface of a cluster. However, this enhancement at the gap of clusters was limited because these clusters were usually placed on the plate substrate. Placed these nanoparticles on the surface of the larger particles, the enhanced point can be moved on any place.

In this study, we tried to prepare polystyrene (PS) particles which have smaller metal particles deposited by the electroplating on their surface.

Experimental: PS beads (<1.0 μm) were used as template particles. The PS dispersion in 50 % ethanol aqueous solution was put on indium tin oxide coated glass substrate to form the colloidal crystalline template.

The flash electroplating was performed with DC power supply with 1 – 10 V in aqueous solutions containing silver ions. After rinsed with distilled water, the particles were observed by scanning electron microscopy.

Photoabsorption spectrum of Ag deposited samples were measured for evaluation of LSPR.

Results and Discussions: SEM images of Ag electroplated with 3 V for 5 s in 0.001 M AgNO3 aqueous solution on the template by 1.0 μm PS beads were shown in Fig. 1. With lower voltage, 1 V, less Ag clusters were generated. With higher voltage, the clusters were rapidly grown and covered the PS beads’ surface so that it is not found the gap between the clusters. Same tendency was found the results with more concentrated silver solution. It is suggested that the optimal condition for placing Ag clusters on the PS beads was the electroplating with 3 or 5 V. It is also indicated that the Ag particles’ size can be controlled by the applied DC voltage and applied period of electrodeposition. In addition, the Ag cluster induced photoabsorption with surface plasmon resonance (SPR) around 480 nm region. The photoabsorption was observed particularly strongly in the brushy structure (using 1.0 μm PS beads and 5 V applied), and it was shown that it was due to the strong electromagnetic field derived from the nanogap structure in the Ag clusters. This also shows that SPR is localized. We have succeeded in preparing the localized surface plasmon resonance (LSPR) active structure and found that its optical properties can be controlled using a very simple method with an electroplating process. These results suggest that one of the possibilities of the helpful to high sensitivity the sensor using the surface enhanced method (Raman, IR, photoluminescence (PL) and more).

Acknowledgement: This work was supported by JSPS KAKENHI Grant Number JP19K05191.

Figure 1
Influence of Fuels and pH on the Activity and Dissolution Stability of Bifunctional Alloy Electrocatalysts
Authors: Kormanyos Attila , Speck Florian Dominik , Savan Alan , Ludwig Alfred , Mayrhofer Karl J. J. , Cherevko Serhiy
Published: December 2020

After two decades of slumber, research on organic fuel cells is getting increasing interest. Organic fuels, such as alcohols provide an attractive avenue to overcome the drawbacks of hydrogen as an energy carrier however, catalysis is still a bottleneck for their efficient oxidation. In most studies almost exclusively primary alcohols (e.g., methanol and ethanol) are investigated as fuels. The major downside of this approach is that these are not “zero emission” systems since CO2 forms as a final product. Moreover, CO evolves as an intermediate, which poisons the catalyst surface leading to deteriorated device performance. A possible solution is to use secondary alcohols, such as isopropanol in which case the product is acetone. A prominent member of the bifunctional electrocatalyst family is PtRu, which proven to be the state-of-the-art electrocatalyst in alcohol oxidation. However, in the case of isopropanol the forming acetone poisons its surface, thus there is an inevitable need for the development of novel catalyst materials circumventing these issues. In general, most research efforts so far have addressed the activity and mechanism of oxidation reactions on bifunctional electrocatalysts, but less is known about the influence of alcohols on their stability during operation. On-line techniques allow an elegant option to study such processes besides activity and to track the formed intermediates in real time.

In this study we employ on-line ICP-MS to map the activity and stability of Pt-rich PtRu and PtIr alloy catalysts towards the electrocatalytic oxidation methanol, ethanol and isopropanol. Material libraries were synthesized by combinatorial reactive magnetron sputtering that allowed precise control over the metal/metal ratio in each sample. To determine both the surface and bulk composition of PtRu and PtIr material libraries XRD, XPS and EDX measurements were performed. Activity and stability of the electrocatalyst samples were studied in both acidic (HClO4) and alkaline (KOH) media and in the presence of the alcohols. The observed trends in the activity and dissolution characteristics of both systems are going to be discussed in detail along with the identification of the possible underlying processes.
Electrochemical Detection of Inverse Emulsion Droplets.
Authors: Park Jun Hui
Published: December 2020

We report electrochemical detection of the collisions of single water droplets in organic solvent using an ultramicroelectrode (UME). Water-in-oil droplets were made from the ultrasonic mixing of organic solvent (e.g., diethylene chloride) and aqueous solution containing the redox species. And emulsion stabilizer as well as the supporting electrolyte were carefully selected and added to perform the attoliter-droplet electrochemistry. With appropriately applied potentials at an UME, we could observe the single emulsion droplet collision phenomena from in the amperometric current-time (i-t) measurement. Emulsions that have established ionic conduction to the collided UME exhibit amperometric current spikes by instantaneous electrolysis of a redox species in single water-in-oil droplets. The size and contact area of the water droplets were also estimated by analyzing the collisional current peaks. On the basis of the collisional events, we could successfully establish a facile water droplets detection system in an organic solvent medium.
Icosahedral Cobalt Bis(dicarbollide) Ions with Bridge Linker and Their Electrochemistry in Aqueous Media
Authors: Fojt Lukáš , Grüner Bohumír
Published: December 2020

Boron cluster compounds (BCC) proved recently promising properties for use in drug design and molecular probes. Their applications in medicine are inherently connected with use of water-based environments. Up to now, the BCC were predominantly characterized in non-aqueous milieus. Therefore, we decided to perform electrochemical research of BCC in water-based electrolytes. We have focused on several boron clusters with structures that follow our previous study on icosahedral cobalt bis(dicarbollide) ions with a central coordination Co(III) atom in phosphate buffers, where we have found the best response for bridge type of exo-skeletal substituent. Therefore, in present study, we decided to focus on the promising structures, in which two 11 vertexes C2B9 dicarbollide ligands are interconnected via short bridge. Such structures may contain side chains usable for bioconjugation experiments.

For our electrochemical experiments, we have used phosphate buffers of different pHs (2-10) and polished glassy carbon electrode. As the bridge structure served these exo-skeletal substituents: sulfur, amino group, tolylene, chlorpehenylene, phenylene, xylylene, byphenylene, phosphoric groups.

The effect of various exo-skeletally substituted cobaltacarboranes (differing in type and length of the side chain) on the electrochemical response was studied. The results show that all parameters, the peak shape, the potential position and the peak current density height are significantly altered by the endo- and exo- skeletal substituents. Within the range of studied substitution, we were able to detect the signals in a broad potential range from E = -1.38 V to E = 1.73 V. From this follows clear possibilities to tune the position of two potential types in the electrochemical window that alternatively correspond either to the oxidation of the core structure of boron polyhedra or the central Co(III). The results also show that the electrochemical methods represent another tool for fast tracking the aggregation phenomena connected with non-classical amphiphilic behavior of boron clusters in aqueous solutions
Understanding the Thermal Safety of Solid-State Lithium Battery: An in-Situ Thermal Study
Authors: Zhang Zhang , Pol Vilas G.
Published: December 2020

The state-of-the-art solid-state lithium batteries (SLBs) using solid electrolytes attracted wide attention due to their high energy density and superior thermal safety. Previously, the thermal safety of SLBs were investigated by thermogravimetric analyses (TGA), differential scanning calorimetry (DSC), or flammability testing. However, these methods can only study the thermal safety of independent electrolyte, not the entire battery simultaneously. A method to quantitatively evaluate the thermal safety of entire SLBs is lacking. Herein, we developed a novel in-situ method to study the thermal safety of an entire coin cell employing multiple module calorimeter (MMC) and battery tester. The MMC can detect the heat flow of a coin cell in the temperature range of 20 to 300 °C with different heating rates, while the coupled battery tester records its open-circuit voltage (OCV). In this work, poly(vinylidene fluoride) (PVDF)-based composite solid-state electrolyte was employed as the model solid electrolyte due to the outstanding compatibility with both cathode and lithium anode, good film forming features, and excellent thermal stability. The all-solid-state LiNi1/3Co1/3Mn1/3O2/Li coin cell was assembled simply by using LiNi1/3Co1/3Mn1/3O2 cathode, PVDF-based solid electrolyte, and Li metal anode without the addition of any liquid electrolyte. For demonstration purpose, the thermal safety of entire solid cell was in-situ investigated and compared with the analogous cell using traditional liquid electrolyte. It is worth noting that the solid-state cell exhibited a thermal stable window up to 177 °C and a small heat release of 189 J g-1 during the thermal runaway of the entire cell. In contrast, the cell using liquid electrolyte delivered a reduced thermal stable window (157 °C) and release a significant amount of heat (812 J g-1). The superior thermal safety of SLBs can be ascribed to the solid-state property and outstanding thermal stability of the PVDF-based solid electrolyte. To the best of our knowledge, this is the first in-situ quantitative study on the thermal safety of the entire solid-state lithium battery. This work highlights a reference for the in-situ quantitative study on the thermal safety of entire SLBs.
Observation of Interfacial Degradation of Solid Electrolytes Against Lithium Metal and Layered Transition Metal Oxides Via in Situ Electrochemical Raman Microscopy
Authors: Zhou Yundong , Hardwick Laurence J.
Published: December 2020

Solid state batteries, utilizing ceramic solid-state electrolytes, are attracting intensive research for their improved safety and possible higher energy density. Solid-state electrolytes can have comparable ionic conductivities to the liquid carbonate electrolytes, for example, Li10GeP2S12 with an ionic conductivity at 1.2 × 10-2 S cm-1 at room temperature. However, the performance of solid state batteries requires improvement to enable long term cycling. The interface instability between the solid electrolytes and electrodes is one of the limiting factors for the utilization of solid state batteries. Traditionally, mostly ex situ surface characterisation techniques such as Raman or x-ray photoelectron spectroscopy can be used to study the buried interfaces within all-solid-state batteries. Raman microscopy, in particular, is a powerful surface characterisation technique and has been used to detect structural and chemical information on electrode interfaces primarily in liquid electrolyte cells. The ability to do in situ observation of the solid electrolyte – electrode interface is paramount for understanding the performance and design interfacial strategies for solid state batteries.

In this study, in situ Raman microscopy and ex situ Raman imaging were adopted to study the interfacial evolution during cycling covering β-Li3PS4, Li10GeP2S12, and Li6PS5Cl electrolytes against Li metal and LiCoO2 or LiNi0.6Mn0.2Co0.2O2. Degradation products at both Li metal side and cathode side were detected. For example, the degradation products of the interface Li6PS5Cl at both Li metal side and LiCoO2 side were resolved [1]. Li2S was formed by Li deposition onto Li6PS5Cl and there were polysulfides, and P2Sx species formation between Li6PS5Cl and LiCoO2 interface. In situ Raman results were correlated with ex situ Raman microscopy from cycled cells. The ex situ Raman imaging also directly visualised the distribution of degradation products. We will demonstrate that in situ Raman microscopy as a powerful tool in the study of electrode/electrolyte interfaces within the solid-state cell. The technique can be translated to alternative solid electrolyte – cathode combinations to understand the operando interfacial evolutions for designing improved all-solid-state batteries.

Y Zhou, C Doerrer, J Kasemchainan, P.G. Bruce, M. Pasta, L.J. Hardwick, Batteries & Supercaps 3(2020)1-7.
Perspective on Cathode Composite Design: Revising Ceramic Processing Choices Toward Low Interfacial Impedance for Garnet-Based Solid-State Batteries
Authors: Kim Kun Joong , Rupp Jennifer L.M.
Published: December 2020

The critical factors that determine the performance and lifetime of solid-state batteries (SSBs) are driven by the electrode–electrolyte interfaces.1,2 The main challenge in fabricating ceramic cathode composites for garnet-based SSBs has been lowering the thermal processing window in which both good contact and low interfacial resistance can be achieved.3 Here, we report an alternative ceramic processing strategy that enables the fabrication of all-solid composite cathodes at an unusually low processing temperature without the use of sintering additives or a fluid electrolyte (polymer-gel, liquid electrolyte). We present specific examples of LiFePO4 and LiCoO2 cathodes with a Li-garnet (Li7La3Zr2O12, LLZO) solid-electrolyte. An infiltration step is used to directly synthesize the LiCoO2 cathode from metal salts in a porous LLZO scaffold, resulting in the formation of the composite cathode (LiCoO2-LLZO) on top of a dense LLZO solid electrolyte. A promising discharge capacity of 118 mAhg−1 (3–4.05 V) with 62 Ohm·cm2 is realized for LiCoO2 with a lithium anode, whereas critical phase instabilities for LiFePO4 are uncovered. Our findings encourage a move away from synthesis techniques that employ particle mixing and sintering to fabricate composites. We provide guidelines on circumventing adverse interphase reactions according to chemistry and ceramic thermal processing budgets in the preparation of these ceramic interfaces as well as on increasing the number of reaction sites. Ultimately, this work provides key ceramic processing guidelines for the preparation of all-solid and high-performing composite cathodes for future Li-garnet SSBs for safe energy storage.

(1) van den Broek, J.; Afyon, S.; Rupp, J. L. M. Interface-Engineered All-Solid-State Li-Ion Batteries Based on Garnet-Type Fast Li+Conductors. Adv. Energy Mater.
2016, 6 (19), 1–11.

(2) Janek, J.; Zeier, W. G. A Solid Future for Battery Development. Nature Energy. 2016, 1–4.

(3) Samson, A. J.; Hofstetter, K.; Bag, S.; Thangadurai, V. A Bird’s-Eye View of Li-Stuffed Garnet-Type Li7La3Zr2O12 Ceramic Electrolytes for Advanced All-Solid-State Li Batteries. Environ. Sci.
2019, 12, 2957–2975.
Impact of Surface Conditioning on Bulk Conductivity of LLZO Garnet Electrolytes
Authors: Grissa Rabeb , Heinz Meike , Battaglia Corsin
Published: December 2020

Li7La3Zr2O12 (LLZO) garnet ceramics are promising electrolytes for high-energy-density all-solid-state lithium-metal batteries. Unlike most ceramic electrolytes, LLZO is compatible with a lithium-metal anode and thus attracts extensive interest in the all-solid-state battery community.

A crucial parameter for a high performance lithium metal battery is a low anode/electrolyte interfacial resistance, which allows a homogeneous distribution of the local current density and thus prevents the undesired lithium dendritic growth during the charging process. Indeed, the lithium carbonate layer formed on the LLZO surface is found to be responsible for a surface lithiophobic character. Many studies reported and proved the possibility to achieve an ultralow lithium-metal/LLZO interfacial resistance <10 Ω·cm2 by different thermal, mechanical and/or chemical surface treatments in order to eliminate this carbonate layer 1–3 or by different coatings with lithiophilic materials4.

In this work, we study the impact of surface conditioning processes on the bulk properties of LLZO using a combination of different surface and bulk techniques including XPS, XRD, TGA and EIS5. We confirm that negligible interfacial resistance <10 Ω·cm2 is obtained after a thermal treatment at 400 °C. However, we demonstrate that thermal treatments >400 °C in argon atmosphere, even though efficient in eliminating the carbonate layer present on the surface, lead to the formation of an only partially lithiated LLZO layer with a resistance contribution of 10 Ω·cm2 at 500°C which increases to 120 Ω·cm2 at 600°C and almost doubles the pellet's resistance (dominated by grain boundaries).

We also show, by impedance spectroscopy, that chemical treatments with acid solutions lead to garnet protonation, by Li+/H+ exchange. An increase in pellet resistance higher than 50 Ω·cm2 is observed and attributed to the formation of the Li7-xHxLa3Zr2O12 phase, with mixed H+/Li+ conduction. This deteriorates the Li+ transference number of the material. Moreover, the degradation of the LLZO surface is also confirmed by XPS from La and Zr chemical shifts after only 30 s exposure to HCl in contrary to 30 s exposure to water. The presence of a protonated phase may favor dendrite formation.

Overall, this study provides a deep understanding of the impact of surface conditioning on garnets bulk properties. It shows that even though surface conditioning allows a low interfacial resistance between LLZO and lithium metal, it may influence the material's bulk electrochemical performance.

References:

A. Sharafi et al. Chem. Mater. 29, 7961–7968 (2017)

Y. Li et al. J. Am. Chem. Soc. 140, 6448–6455 (2018)

H. Huo et al. Nano Energy 61, 119–125 (2019)

W. Luo et al. Adv. Mater. 29, 1–7 (2017)

R. Grissa, M. Heinz, C. Battaglia, submitted
Sodium Niobium Sulfides As Active Materials for High Capacity Sodium Secondary Batteries
Authors: Nasu Akira , Sakuda Atsushi , Tatsumisago Masahiro , Hayashi Akitoshi
Published: December 2020

All-solid-state sodium batteries with high safety and high energy density are expected as next generation rechargeable batteries. Active materials play the key role to develop the capacity and the reversibility of the batteries. We have focused on the transition metal sulfides as the active materials. We have reported that the all-solid-state cells using TiS2 operated reversibly[1]. In term of the practical use, the further increase of the capacity is important. One of the solutionsll is the application of sodium rich transition metal sulfides as active materials. In previous reports, the several new crystal polymorphs of Na2TiS3 were produced by melt quenching and mechanochemical reaction [2, 3]. P2-type layered Na2TiS3 obtained by melt quenching showed twice higher capacity than that of the stable phase of O3-type layered Na2TiS3. Cubic rocksalt phase Na2TiS3 prepared by mechanochemical process was also a metastable phase with high capacity. The metastable phases with high ionic conductivity are advantageous for insertion/extraction. Sodium niobium sulfides have sodium-rich compositions such as Na3NbS4. In lithium batteries, cubic rocksalt Li3NbS4 synthesized by mechanochemical process showed the reversible capacity of 400 mAh g-1 [4]. In this study, we have synthesized Na3NbS4 and optimized their crystal polymorphs by melt quenching and mechanochemical process for high capacity electrode.

Electrode materials with the composition of Na3NbS4 were prepared by solid phase reaction or mechanochemical reaction of Na2S, NbS2 and S. DTA curves of the mixture of Na2S, NbS2 and S with the Na3NbS4 composition suggested that phase transition occurred at 630oC. XRD patterns of Na3NbS4 prepared by melt quenching from 700oC showed that O3-type layered phase were obtained. The all-solid-state cells using the layered Na3NbS4 as active materials showed 80 mAh g-1, suggesting that the O3-type sturucture was not suitable for sodium extraction/insertion. On the other hand, the mechanochemical process produced the new metastable phase of Na3NbS4. The all-solid-state cells using the new phase showed the increment on the capacity of 240 mAh g-1. The new crystal polymorph of Na3NbS4 has also been profitable for sodium extraction/insertion. The newly developed Na3NbS4 is a promising active material with high capacity for all-solid-state sodium secondary batteries.

Reference
s
:

[1] A. Hayashi, K. Noi, A. Sakuda and M. Tatsumisago, Nat. Commun., 3 (2012) 856.

[2] A. Nasu, M. Otoyama, A. Sakuda, A. Hayashi, and M. Tatsumisago, Chem. Lett., 48 (2019) 288.

[3] A. Nasu, M. Otoyama, A. Sakuda, A. Hayashi, and M. Tatsumisago, J. Ceram. Soc. Jpn., 127 (2019) 514.

[4] A. Sakuda, T. Takeuchi, K. Okamura, H. Kobayashi, H. Sakaebe, K. Tatsumi and Z. Ogumi, Sci. Rep., 4 (2014) 2.
Particle Size Effects of the Ni-Rich Cathode Material in All-Solid-State Li-Ion Batteries
Authors: Heo Kookjin , Lee Jongkwan , Kim Min-Young , Im Dae-yeong , Gil Woo-ram , Park Won-seok , Lim Jinsub
Published: December 2020

All-solid-state Li-ion batteries (ASLBs) may be promising candidate to solve the problem because it uses non-flammable inorganic solid electrolytes as an electrolyte and separator. However, ASLBs has serious drawback such as low ionic conductivity compared to liquid electrolyte and have a large interfacial resistance between positive electrode and solid electrolyte in positive electrode. In these regards, reducing particle size of the cathode material can be positive affect to increase the contact area between cathode material and solid electrolyte in the positive electrode to decrease the interfacial resistance. In addition, high capacity Ni-rich cathode material generally was used for high energy density in ASLBs.

In this work, we report on the particle size effects of the Ni-rich cathode material synthesized by co-precipitation method in all-solid-state Li-ion batteries. For comparison of the size effect, the physical, chemical, and electrochemical properties were evaluated by X-ray diffraction, field-emission scanning electron microscopy (FE-SEM), electrochemical impedance spectroscopy (EIS) and galvanostatic tests.
Liquid Structure and Transport Properties of the Deep Eutectic Solvent Ethaline
Authors: Zhang Yong , Poe Derrick , Heroux Luke , Squire Henry John , Doherty Brian , Long Zhuoran E. , Dadmun Mark , Gurkan Burcu , Tuckerman Mark E. , Maginn Edward J.
Published: December 2020

A range of techniques including physical property measurements, neutron scattering experiments, ab initio molecular dynamics and classical molecular dynamics simulations are used to probe the structural, thermodynamic, and transport properties of a deep eutectic solvent comprised of a 1:2 molar ratio of choline chloride and ethylene glycol. This mixture, known as Ethaline, has many desirable properties for use in a range of applications and therefore understanding its liquid structure and transport properties is of interest. Simulation results are able to capture experimental densities, diffusivities, viscosities, and structure factors extremely well. The solvation environment is dynamic and dominated by different hydrogen bonding interactions. Dynamic heterogenities resulting from hydrogen bonding interactions are quantified. Rotational dynamics of molecular dipole moments of choline and ethylene glycol are computed and found to exhibit a fast and slow mode.
Process Engineering Challenges for the Development of Electrolytic Reduction of Uranium Oxide in Molten LiCl-Li2O
Authors: Chamberlain Jarom L , Burak Adam J , Gonzalez Mario Alberto , Simpson Michael Forrest
Published: December 2020

Electrolytic uranium oxide reduction has the potential to be a key process for recycling spent fuel from commercial light water reactors to advanced nuclear reactors—including molten salt reactors and metal fueled reactors. However, several problems with the process have been identified that need to be addressed to support efficient, cost-effective commercial implementation. Process optimization requires attention to metal corrosion, anode stability, cell efficiency, and cathode product purity. Generation of oxygen bubbles at the anode combined with high temperature (650oC) and molten chloride salt (LiCl + 1 wt% Li2O) create a highly oxidizing environment for metals needed for salt containment and shrouding of the anode. The current standard choice for the inert anode is platinum metal, which has fairly good stability in the system. But given the high cost of platinum, alternative anode materials need to be discovered. Efficient removal of oxygen bubbles requires use of a shroud around the anode. The easy fabricability of metals makes them a reasonable choice for the shroud material, but corrosion due to interaction with the salt and oxygen needs to be minimized. Cell efficiency is affected by hydroxide impurity in the salt. Methods for removing water and hydroxides from the salt will be reported that improve cell efficiency. Cell efficiency can also be affected by controlling the reduction mechanism. Uranium oxide can either be reduced chemically by reaction with electrochemically generated lithium atoms or electrolytically with direct reduction of UO2. The reduction mechanism also affects the buildup of entrained lithium oxide in the cathode product. Entrained lithium oxide is problematic as it gets carried on to subsequent processing steps such as electrorefining and molten salt oxidation.