bluuebunny/crossref_metadata_2025 huggingface dataset:
Development of Reagentless Fluorescence Immunosensors for Continuous Analyte Monitoring
Authors: Fercher Christian , Islam Jiaul , Corrie Simon
Published: December 2020

Fluorescence-based immunodiagnostics are an emerging field in biosensor development and exhibit several advantages over traditional detection methods. While various affinity biosensors have been developed to generate a fluorescence signal upon sensing varying concentrations of analytes, reagentless, reversible and continuous monitoring of complex biological samples remains challenging. Here, we aimed to genetically engineer biosensors based on single-chain antibody fragments (scFv) that are site-specifically labelled with environmentally sensitive fluorescent unnatural amino acids (UAA). A rational design approach resulted in quantifiable analyte-dependent changes in peak fluorescence emission wavelength and enabled antigen detection in vitro. Incorporation of a polarity indicator in proximity of the antigen binding interface generated a titratable wavelength blueshift with nanomolar detection limits.

In order to ensure continuous analyte monitoring, scFv candidates with fast binding and dissociation kinetics were selected from a genetic library employing a high-throughput display and affinity screening approach. Initial rankings were further refined towards rapid dissociation kinetics using bio-layer interferometry (BLI) and surface plasmon resonance (SPR). The most promising candidates were expressed, purified to homogeneity, and tested for their potential to detect varying concentrations of the target antigen in a continuous microfluidics-based assay. Variations of dissociation kinetics within an order of magnitude were achieved without compromising specificity of the antibody fragments. This approach is generally applicable to numerous antibody/antigen combinations and currently awaits integration in a wide range of assay platforms for one-step protein quantification.

Figure 1
Setting up the Reference Performance Tests of an Ageing Campaign for Non-Intrusive Diagnosis on Li4Ti5012 and LiMn1-XFexPO4 Based Cells
Authors: Brunetaud Ruben , Legrand Nathalie , Vinassa Jean-Michel , Briat Olivier , Capitaine Armande , Dubarry Matthieu
Published: December 2020

Non-intrusive diagnosis and prognosis methods are increasingly adopted to track Li-ion batteries ageing without additional cost due to destructive processes for post-mortem analyses. To qualify and quantify internal degradation mechanisms of a cell, Incremental Capacity Analysis (ICA) and Differential Voltage Analysis (DVA) have proven themselves to provide precise outputs on the battery state of health. These differential methods require close-to-equilibrium Open Circuit Voltage (cte-OCV) measurements to decipher ageing paths depending on the utilization.

This poster presents an ageing campaign preliminary study on some Graphite//LiMn1-xFexPO4 and Li4Ti5O12/Ni1-x-yMnxCoyO2 based cells. It focuses on the reference performance tests chosen to be the most complete on both cell and electrode levels.

As the battery cte-OCV measurement is a lengthy process of at least 25h, the reference tests should be well-defined to acquire as many data as possible in a single shot. A comparison is carried between constant current measurements and incremental charges with relaxation (GITT) to approach thermodynamic equilibrium, as well as the conditions and sampling rates to leverage differential method curves without further smoothing.

The electrode study is implemented as references for models to evaluate both thermodynamic and kinetic behaviours of the battery components. To find out the closest half-cell replicates, electrode versus lithium coin cells are compared with a 3 electrodes PAT-cell assembly depending on the temperature and measurements.
Influence of the Stretching on the Ionic Conductivity of Solid Polymer Electrolyte
Authors: Jeanne-Brou Roselyne , de Moor Gilles , Charvin Nicolas , Flandin Lionel , Bouchet Renaud , Devaux Didier
Published: December 2020

Conventional Li-ion batteries contain flammable liquid based electrolytes that can leak and react violently with the environment leading to a fire.[1] A solution is to replace the liquid electrolyte by a Solid Polymer Electrolytes (SPEs). Indeed, SPEs are of interest thanks to their flexibility, process easiness, lack of volatile compounds, and chemical and electrochemical stability toward one the most promising anode material, i.e. Li metal.[2]

Among the variety of SPEs reported in literature, Poly(ethylene oxide) (PEO) doped with a Li salt is the most studied polymer electrolyte.[3] Indeed, PEO contains ether coordination sites that efficiently dissociate Li salts and its flexible macromolecular backbone enables ionic transport. Ionic conduction in SPEs depends for a large part on the dynamics of the polymer chains (ref. Devaux et al. SSI 2012). Therefore, a fine understanding of the relationship between polymer chain conformation and ionic conductivity is necessary to pave the way toward an optimized SPE. The goal being to produce a SPE suitable for a Li metal battery operating at room temperature.

In this study, we report first on a setup designed to stretch SPE coupled with impedance spectroscopy in controlled Argon atmosphere. As an example, Figure 1 shows the impedance spectra under Argon at room temperature of a SPE made of high molecular weight PEO laden with LiTFSI (EO:Li =25) at different elongations (ε). Then, in-plane and through-plane conductivity of SPEs have been compared. 3 different type of SPEs has been studied of i) reference PEO/LiTFSI, ii) block copolymer electrolyte comprising polystyrene and PEO blocks (ref. Bouchet et al, Macromolecules 2014), and iii) composite electrolytes where PEO or the block copolymer is mixed with inorganic particles.

References

[1] D. Lisbona, T. Snee, Process Saf.
Environ., 89 (2011) 434.

[2] W. Xu et al., Energy Environ. Sci., 7 (2014) 513.

[3] R C. Agrawal, G. P. Pandey, J. Phys, D, 41 (2008) 223001.

Figure 1
Advanced Hybrid Electrodes Based on Polyoxometalate–Activated Carbon for Electrochemical Energy Storage in Li-Ion Batteries
Authors: Bosch Georg-Maximilian , Treffehn Patrick , Dsoke Sonia
Published: December 2020

For fast charging and speeding up an electric vehicle, the high power of supercapacitors is needed. Driving a long distance can be realized by the high capacity of a battery. A combination of the advantages of supercapacitors and batteries in one material can bring novel possibilities for electric mobility in the future. Therefore, hybrid materials have attracted much attention in recent years, since they can simultaneously deliver high power and high energy density [1]. Polyoxometalates (POMs), for example, the α-Kegging type: y H+·[XM12O40]-y, are well known as very stable towards oxidation and reduction. These materials show fast and reversible multi-electron transfer reactions [2], and can, therefore, be considered as a promising candidate. In previous experiments, the properties of the POM were optimized for the use in an organic electrolyte by temperature treatment, and the cycling stability of the material improved by 20-times [3].

In this work, activated carbon (AC) was used to prepare POM@AC hybrid material. Due to the absorption properties of the activated carbon, the maximum POM amount was 45 %-wt. The high- temperature optimization of the POM was achieved in one step together with the activated carbon. The combination and optimization of the two materials enables increased cycling stability, as well as a higher capacity with respect to the two single materials (Fig.1). SEM revealed a smaller POM particle size. Therefore the increased capacity can be related to a higher surface of the active material. Further, the hybrid material was characterized by XRD, TGA-DSC, and electrochemically.

Future experiments will focus on increasing the amount of POM on the activated carbon. A higher percentage of POM in the hybrid material, as well as a better distribution of the particles on the surface, can lead to an increase in capacity.

Acknowledgment

This work contributes to the research performed at CELEST (Center for Electrochemical Energy Storage Ulm-Karlsruhe).

[1] M. Genovese, K. Lian, Polyoxometalate modified inorganic–organic nanocomposite materials for energy storage applications: A review, Curr. Opin. Solid State Mater. Sci. 19 (2015) 126–137.

[2] M. Sadakane, E. Steckhan, Electrochemical properties of polyoxometalates as electrocatalysts, Chem. Rev. 98 (1998) 219–237.

[3] G.-M. Bosch, S. Dsoke, Paper in progress, (2020).

Figure 1
Phase-Purity Na3V2 (PO4) 2F3 Embedded in the Carbon Matrix through Easy Polyol Synthesis As a Potential Cathode of High Performance Sodium Ion Batteries
Authors: Park Young , Park Sohyun , Sambandam Balaji , Lee Jun , Putro Dimas Yunianto , Kim Jaekook
Published: December 2020

In this study, a pseudo-layered Na super-ionic conductor (NASICON) of Na3V2(PO4)2F3 (NVPF)/C cathode for sodium-ion batteries is prepared successfully using a easy polyol refluxing process without any impurity phases. We confirmed that NVPF have tetragonal NASICON-type lattice with a space group of P42/mnm through The X-ray diffraction and Rietveld refinement. In this preparative method, polyol is used a solvent as well as a carbon source. The presence of nanosized NVPF particles in the carbon network is confirmed by high-resolution transmission electron microscopy (HR-TEM) and field-emission scanning electron microscopy (FE-SEM). The existence of carbon is analyzed by Raman scattering and elemental analysis. When applied as a Na-storage material in a potential window of 2.0–4.3 V, the electrode exhibits two plateaus at 3.7 and 4.2 V with an electrochemically active V3+/V4+ redox couple. In addition, after Na3V2(PO4)2F3/C was cycled about 1,500 at 15C, It maintaion capacity of ~ 88%. Moreover, at high current densities of 30 and 50 C, Na3V2(PO4)2F3/C cathode retains the specific discharge capacities of 108.4 and 105.9 mAh·g–1, respectively, the structural stability of the material prepared through a facile polyol refluxing method.
Redox Synthesis and Characterization of Layered LiNi1/3Co1/3Mn1/3O2 for Rechargeable Lithium Ion Batteries
Authors: Song Moonsoo , Lee Seulgi , Mathew Vinod , Alfaruqi Muhammad Hilmy , Lee Jun , Kim Jaekook
Published: December 2020

This study reports on the characterization of layered Li (Ni1/3Co1/3Mn1/3)O2 (x = 1.05 and 1.1) cathodes synthesized by a simple ambient temperature redox synthesis and post-heat treatment with added lithium sources.

Synchrotron XANES and ICP measurements were performed to confirm the change in oxidation state during the redox reaction and the successful control of the stoichiometric ratio of ternary transition metal oxides (Ni2+
0.33Co3+
0.35Mn4+
0.32Oy).

In the FE-SEM image, loosely aggregated particles with an average diameter of 60nm appeared in the intermediate product, and the particle size grew to several hundred nanometers after lithiation at elevated temperature.

The electrochemical performances at 14 mAg-1 in the potential range of 3.0–4.3V vs. Li/Li+ indicated that reasonable specific capacities and cycle performances are registered for all the prepared cathodes. especially, the Li1.05(Ni1/3Co1/3Mn1/3)O2 composition demonstrated the highest capacity retention value (~99%) after 50 cycles and better rate performances (104, 91, 76, and 67 mAhg-1) at high current densities (229, 457, 914, and 1429 mAg-1 respectively).
Stabilization of Li Metal Powder Anodes on Cu Foil Current Collectors Using Thin Carbon Interlayers
Authors: Jin Dahee , Roh Youngjoon , Lee Hongkyung , Ryou Myung-Hyun , Lee Yong Min
Published: December 2020

Due to the highest theoretical capacity, the Li metal anode is considered to be the most ideal anode materials for large-scale batteries, if the problems related to Li dendrite growth can be overcome. Obviously, as most people know well, enlarging the surface area of the Li metal has quite an influence on lower the effective current density to suppress the lithium dendrite growth of lithium metal secondary batteries (LMSB). For this reason, lithium metal powder (LiMP) has attracted much attention for use in electrodes because of its 4.5 times higher surface area compared to lithium foil. However, the electrolyte can be fully penetrated to the LiMP electrode due to its porosity, which leads to galvanic corrosion between Cu foil and LiMP particles. Furthermore, repeated cycling deepens the delamination of lithium particles from Cu foil and results in excess dead lithium particles.

Herein, we address this problem by coating the submicron-thickness (~600 nm) carbon interlayer on Cu foil for the LiMP electrode. Despite the LiMP electrode that exists under the electrolyte, the nanoscale carbon interlayer plays an important role in enhancing the adhesive strength between LiMP particle and Cu foil. To confirm the role of the carbon interlayer, we succeeded in quantifying the adhesive strength at the Li/Cu interface for the first time using a surface and interfacial cutting analysis system (SAICAS). Furthermore, the seeding effect of the carbon interlayer in Li/Li symmetric cells and improving electrochemical performance in thin LiMP (40 μm) based cell.
Model Approach on Crack Growth within High Nickel Cathode Materials
Authors: PARK SUN HO , Park Joonam , Song Jihun , Ryou Myung-Hyun , Lee Yong Min
Published: December 2020

Lithium ion batteries (LIBs) has attracted much attention to apply to a variety of application or device systems having different operating systems such as current rates (C-rates), temperatures, and depth-of-discharge (DOD). Therefore, it is important to predict the capacity retention of LIB under different operating conditions. In order to predict the capacity of LIB, the particular main degradation factors such as solid electrolyte interphase (SEI), cracks or electrolyte depletion should be considered. Formation of SEI which is the main degradation factor has been normally used in the model so far. However, as the Ni content in cathode active materials increases and the LIB requires long cycle life, cracks within the particle has been formed as one of main causes for LIB degradation. This formation of cracks is highly related to the cycle numbers and DOD. Therefore, the related research is still stayed in place. In this study, our group have assumed that formation/growth of SEI on anode surface and crack phenomenon would be the main degradation factors in the LIB. And we have tried setting up the model with different degradation effects of DOD and the number of cycles. We hope this life prediction model with a few fitting parameters are fitted to a particular cell.
Surface Double Coating of LiNiaCobAl1-a-bO2 (a > 0.85 ) Cathode with Tiox and Li2CO3 to Apply a Water-Based Hybrid Polymer Binder to Li-Ion Batteries’ Preparation
Authors: Watanabe Tatsuya , Hirai Kouji , Ando Fuma , Kurosumi Shoudai , Ugawa Shinsaku , Lee Hojin -J , Irii Yuta , Maki Fumihiko , Gunji Takao , Wu Jianfei , Ohsaka Takeo , Matsumoto Futoshi
Published: December 2020

Recently a water-based polymer binder has been getting much attention to simplify the production process of lithium ion batteries (LIBs) and reduce their cost. The surface of LiNiaCobAl1-a-bO2 (a > 0.85, NCA) cathode with a high voltage and high capacity was coated doubly with water-insoluble titanium oxide (TiOx) and Li2CO3 layers to protect the NCA surface from the damage caused by contacting it with water during its production process. The TiOx layer was at first coated on the NCA particle surface with a tumbling fluidized-bed granulating/coating machine for producing TiOx-coated NCA. However, the TiOx layer could not coat the NCA surface completely. In the next place, the coating of the TiOx-uncoated NCA surface with Li2CO3 layer was conducted by bubbling CO2 gas in the TiOx-coated NCA aqueous slurry on the ground that Li2CO3 is formed through the reaction between CO3
2- ions and LiOH residua on the TiOx-uncoated NCA surface, resulting in the doubly coated NCA particles (TiOx/Li2CO3-coated NCA particles). The Li2CO3 coating is considered to take place on the TiOx layer as well as the TiOx-uncoated NCA surface. The results (Fig.1) demonstrate that the double coating of the NCA surface with TiOx and Li2CO3 allows for a high water-resistance of the NCA surface and consequently the TiOx/Li2CO3-coated NCA particles cathode prepared with a water-based binder possesses the same charge/discharge performance as obtained with “water-uncontacted” NCA particles cathode prepared using the conventional organic solvent-based polyvinylidene difluoride binder.

Fig. 1 Charge/discharge cycle performance obtained with the cathodes prepared from (black circle) the slurry consisting of pristine NCA, PVdF and AB, (red circle) the water-based slurry consisting of TiOx/Li2CO3-coated NCA (the slurry was kept for 7 days under CO2 atmosphere), TRD202A, CMC and AB, (blue circle) the water-based slurry consisting of TiOx-coated NCA, TRD202A, CMC and AB and (green circle) the water-based slurry consisting of Li2CO3-coated NCA (the slurry was kept for 1 h under CO2 atmosphere), TRD202A, CMC and AB at the charging/discharging rate of 0.1 C at 25℃.

Figure 1
Effect of Na3BO3 Addition to Nasicon-Type Na3V2(PO4)3 single-Phase All-Solid-State Battery
Authors: Shirai Nobuaki , Nishio Akira , Inoishi Atsushi , Minami Hironari , Izumi Hiroaki , Okada Shigeto
Published: December 2020

All-solid-state rechargeable batteries(ASSBs) have been attracting much attention in recent years as an alternative to conventional lithium ion batteries because ASSBs have various advantages such as safety with nonflammable inorganic electrolytes, high energy density. While solid electrolytes which show excellent conductivity of 10-2 S cm-1 were reported in the sulfide-based materials, particularly oxide-based solid-state cell shows large interfacial resistance and prevents commercialization of ASSBs. To address this issue, we have revealed NASICON-type Na3-xV2-xZrx(PO4)3 operates as “single-phase” all- solid-state batteries that were fabricated from a single material [1]. In addition, we have reported the addition of Li3BO3 to a single-phase all-solid-state battery using NASICON-type Li1.5Cr0.5Ti1.5(PO4)3 (LCTP) to improve the packing density and the lithium-ionic conductivity [2]. In this work, based on the above results, we investigate the effect of the addition of Na3BO3 to the NASICON-type Na3V2(PO4)3 (NVP) to enhance their electrochemical properties.

NVP were prepared using conventional solid-state reaction method. NaH2PO4 and V2O5 were mixed in a molar ratio of 3:1. The mixture were sintered twice at 900℃ for 20 h with intermediate regrinding. Both sintering were performed under Ar + H2 (5 vol.%) atmosphere. To obtain Na3BO3, NaOH and H3BO3 were mixed in a molar ratio of 3.2:1 inside an Ar-filled glove box and heated at 400℃ and 450℃ under Ar atmosphere. The obtained NVP was pelletized and annealed at 900℃ for 5 h under Ar + H2 atmosphere. To prepare a NVP-Na3BO3 composite pellet, NVP powder and Na3BO3 powder were mixed in a molar ratio of 95:5 and sintered under the same condition. A thin platinum layer was sputtered on both sides of the pellet as a current collector. Electrochemical measurements were carried out with HS cell (Hohsen Corp.) as the experimental cell.

Figure 1a and 1b show the SEM images of NVP and NVP-Na3BO3. As is clear from them, it is found that by Na3BO3 addition to NVP, many voids between the NVP particles are filled and the packing density is improved. Regarding the cyclability of the NVP-Na3BO3 single-phase cell, a reproducible strange behavior with increasing the utilization on cycling is observed as shown in Figure 1c. However, the similar behavior has been reported for other NVP single-phase batteries [1]. It seems that the conduction path in the system develops and the area that can be used as cathode/anode increases with repeated cycling.

Acknowledgement

This work was supported by Element Strategy Initiative of MEXT, Grant Number JPMXP0112101003.

References

[1] A. Inoishi, T. Omuta, E. Kobayashi, A. Kitajou, S. Okada, Adv. Mater. Interf., 4 (2017) 1600942.

[2] A. Nishio, A. Inoishi, A. Kitajou, S. Okada, J. Ceram. Soc. Japan,
127 (1) (2019) 18-21

Figure 1
Application of Porous Carbon Material As Electrode Material of Polyvalent Cation Electric Double Layer Capacitor (EDLC) for High Capacity
Authors: Okamura Tsubasa , Nakagawa Kiyoharu
Published: December 2020

An electric double layer capacitor (EDLC) is charged and discharged by the physical adsorption and desorption of electrolyte ions on the electrode surface. EDLC has the advantage that it can be charged and discharged at high speed and has a long life. EDLC is used in memory backup power supplies for personal computers and energy recovery systems for power regenerative brakes in hybrid vehicles and other applications. Therefore, higher energy density is required.

E = 1/2 CV2 ... (1)

Therefore, the energy density increases by increasing the electrostatic capacity and the potential. In the conventional adsorption and desorption of monovalent cations, only one electron can be transferred per cation. Therefore, by adsorption / desorption of divalent cations, two electrons can be exchanged for each cation. Therefore, it was considered that the capacitance can be increased by using an electrolyte solution of divalent cations.

In this study, Li + was used as the monovalent cation and Ca2 + was used as the divalent cation. As the anion, Li +, Ca2 + and ClO4
- and BF4
-, which have a stable anion structure, were used. An organic electrolyte with a wide potential window was used. Propylene carbonate (PC) and γ-butyrolactone (GBL), which are commonly used in EDLC research as a solvent for organic electrolytes, can dissolve the electrolyte used. Was used.

As a result, the capacitance increased when Ca2 + was used as the cation. This is thought to be due to the increase in electron transfer due to the use of the divalent cation. In addition, when GBL is used as the solvent, the electrostatic capacity is further increased. The capacity was increased. We considered that there was a difference in the solvation structure, and evaluated the solvation structure using Raman spectroscopy. As a result, when GBL was used, the coordination number of the solvent molecule decreased and solvation It was thought that the size of the electrode became smaller, the amount of adsorption to the electrode increased, and the capacitance increased.
Electrochemistry of Solvent-Free Liquid Quinones
Authors: Penn Emily E , Baclig Antoino C , Ganapathi Devi , Chueh William C.
Published: December 2020

Redox flow batteries are a promising candidate for grid energy storage due favorable scaling and cyclability but are limited by low energy density due to poor solubility of active species in both aqueous and organic solvent. To increase the energy density we investigate the use of a solvent free liquid quinone electrolyte, resulting in high active species concentration (>10M). Well studied in aqueous and organic solvents, the electroreduction of quinones has been shown to strongly depend on the solvent [1] and supporting electrolyte [2]. The absence of inert solvent poses additional challenges due to mass transport and reaction effects in highly concentrated solutions [3]. Here we characterize the physical and electrochemical properties of 2,3,5-trimethyl-1,4-benzoquinone, ranging in concentration from a dilute solution in inert organic solvent to a highly concentrated solvent-free liquid quinone. Using ultramicroelectrode techniques, diffusion and redox kinetics are determined for solvated and solvent free liquid quinones to investigate the feasibility of this material for use as a solvent free redox flow battery electrolyte.

References:

[1] M. Quan, D. Sanchez, M. F. Wasylkiw, D. K. Smith, J. Am. Chem. Soc. 2007, 129, 42, 12847-12856

[2] D. Pletcher, H. Thompson, J. Chem. Soc., Faraday Trans. 1998, 94, 3445-3450

[3] R. B. Morris, K. F. Fischer, H. S. White, J. Phys Chem. 1988, 92, 5306-5313
Versatile Battery Insertion Materials: Crystal Structure and Electrochemistry
Authors: Sada Krishnakanth , Barpanda Prabeer
Published: December 2020

Rechargeable battery technologies became the spotlight of global scientific research in the quest to address growing energy demand. Currently, Li-ion batteries are unanimously occupied consumer electronic sector. These are mostly depending on only two transition elements such as Cobalt (Co) and Nickel (Ni) in popular cathodes LiCoO2 and LiNi1/3Mn1/3Co1/3O2 (NMC). The resource constraints of Co and Ni have paved away for alternate redox chemistry. In this scenario, manganese and vanadium-based layered materials are promising to owe their low-cost, resource-friendly nature with high operational safety. Moreover, the multiple redox states associated with these transition metals are promising to design high energy density cathodes.

Here, we worked on the A2M3O7 (M= V, Mn) class of cathode materials. This family of materials exhibits polymorphism and multiple cationic redox properties. Further, bond valence sum energy calculations (BVSE) discovered a very low migration barrier of the alkali-ion (A) site. It inspired us to examine the intercalation properties of different ions including Li, Na, K and Zn. In each case, we observed interesting crystal chemistry with self-ion exchange property. The residual ions after self-ion exchange acted as pillars to lash out structural collapse during (de)intercalation. The ternary layered Na-Mn-O based metal oxide (Na2Mn3O7) was synthesized using different synthetic routes to tune the size and morphology of Na2Mn3O7 particles. The phase pure Na2Mn3O7 crystallizes in a triclinic layered structure (s.g. P-1). It consists of Mn in major +IV and minor +III oxidation states with electrochemically active Mn4+/Mn3+ redox center. The as-synthesized powder material worked as a versatile cathode for the Li, Na, K and Zn-ion batteries1-4. The systematic electrochemical studies were carried in both the aqueous and non-aqueous electrolytes. It delivered a reversible capacity of ~160, ~140, ~134 and ~330 mA h g-1 respectively with Li, Na, K and Zn metal foil as an anode in half-cell architectures. The detailed (de)intercalation mechanism along with diffusional studies of the various alkali-ions (Li/Na/K) along with Zn-ion will be described to present Na2Mn3O7 as a versatile cathode material.

References:

Adamczyk, V. Pralong, Chem. Mater., 2017, 11, 4645.

Sada, B. Senthilkumar, P. Barpanda, ACS Appl. Energy Mater., 2018, 12, 6719.

Sada, B. Senthilkumar, P. Barpanda, ACS Appl. Energy Mater., 2018, 10, 5410.

Sada, P. Barpanda, MRS Adv., 2019, 49, 2651-2657.
Li-Metal Anode in Dilute Electrolyte Lifsi/TMP: Electrochemical Stability Using Ab-Initio and Classical MD Simulations
Authors: Galvez-Aranda Diego Eduardo , Seminario Jorge M.
Published: December 2020

Ab initio and classical molecular dynamics simulations are performed for Li+ conducting electrolytes based on trimethyl phosphates (TMP) and lithium bis(fluorosulfonyl)imide (Li+FSI−) salt in contact with a Li-metal electrode. We focused on the electrolyte, interfacial electrolyte – Li-metal electrode, and lithium reference electrode – electrolyte – Li-metal electrode to study diffusion and activation energy barriers of the Li+ ion, electrochemical and thermal stability of the interface electrode electrolyte, and potential behavior of the Li-metal electrode, respectively. Our results show that in the most stable state Li+ ions are tetrahedrally coordinated to three TMPs and one FSI–. The decomposition pathway of the LiFSI salt when in direct contact with the Li-metal anode starts with defluorination of FSI− , rapidly losing F− to the lithium surface, forming LiF species. The remaining FSO2NSO2−2 with the addition of 2e− from the Limetal decomposes into SO2−2 and NFSO2−2. SO2−2 deposits on the Li-surface and decomposes into Li2O and Li2S. The remaining NFSO2−2 defluorinates, losing F− ion to the lithium surface, resulting in LiF and the remaining NSO2−1 deposits on the lithium surface and decomposes in the following picoseconds, forming several binary compounds such as Li3N, Li2S and Li2O. In contrast, when the salt is solvated by the TMP molecules, avoiding a direct contact with the Limetal electrode, only one defluorination occurs, decomposing the FSI− into FSO2NSO2−2 and a F–. A similar mechanism is followed when a second FSI− salt is in contact with this new formed SEI. The two anions remain stable as they are solvated by the TMP molecules. We also analyzed the open circuit potential energy (OCPE) of the Li-metal electrode during the SEI formation. OCPE is calculated from the average local potential profile difference within the Li-metal electrode and a pristine Li-crystal reference electrode (LRE). When no SEI is formed, the Li-metal electrode has an average OCPE of +0.36 eV vs LRE. Due to the formation of a SEI, the Li-metal electrode has an average OCPE between -0.07 and -0.21 eV vs LRE. The OCPE of the Li-metal electrode decreases by ~0.42 eV when a SEI is formed. Using the data obtained from the ab initio simulations and using machine learning algorithms such as classification and clustering a classical MD model was developed to study the SEI evolution as the charging process takes place in a battery using Li-metal as anode and the TMP/LiFSI as electrolyte.

Figure 1
Synthesis and Electrical Properties of Mixed Anion Fluorosulfide Ba18F18in8S21
Authors: Tsukamoto Tomoki , Tachibana Shintaro , Orikasa Yuki
Published: December 2020

Fluoride-ion batteries that utilize the multi-electron reaction of metal cation have the potential to far improve the energy density compared with the current lithium-ion batteries.1) In addition, the all-solid-state fluoride-ion battery that uses solid electrolyte is attracting great expectations as a battery system that has both safety and high energy density and that can open up new applications. The fluoride-ion solid conductors such as PbSnF4 and Ba1-xLaxF2+x have been widely studied for decades. Although PbSnF4 has a high ionic conductivity of 1.6 mS cm-1, the potential window is narrow, and a high voltage secondary battery cannot be realized by using PbSnF4. Although Ba1-xLaxF2+x has a wide potential window, the conductivity is 0.2 mS cm-1 at 50°C, which is not suitable for practical use at an ambient temperature. To our knowledge, a solid electrolyte that has both high ionic conduction and a wide potential window has not been found at present and the further development of materials is required.

In this study, we have extended the search area to mixed fluoride compounds containing sulfide ion due to its high polarizability. For the crystal structure of the fluorosulfide compound, Ba18F18In8S21 exhibits unique domain structure having Ba-F structure.2) We report the synthesis and electrical property of Ba18F18In8S21.

According the literature, 2) we prepared Ba18F18In8S21 by solid state synthesis. In an Ar atmosphere, BaS:BaF2:In:S = 3:3:4:6 were weighed in molar ratio and mixed in a mortar. The pelletized sample was sealed in vacuum and calcined at 800 °C. From the result of XRD, it was confirmed that the prepared samples contained Ba18F18In8S21 crystal phase with BaF2 and BaS impurities. Therefore, it is necessary to improve the synthesis condition. Since sulfur exhibits a boiling point of 444 °C and indium metal has a melting point of 156 °C, two atoms might be deficient during the calcination. Therefore, In2S3 was used without using sulfur powder and indium metal, and synthesis was performed at a lower temperature of 700 °C. XRD pattern of the latter prepared powder can be indexed with a space group of the reported Ba18F18In8S21, and the lattice constants were a = b = 22.152 Å and c = 12.642 Å. Although this value is equivalent to the literature,2) there was small amount of BaF2 impurity.

In order to evaluate the electrical property of the obtained sample, AC impedance measurement was performed by using two-electrode cell. The conductivity at 140 ° C was the order of 10-8 S cm-1.

M. Reddy, M. Fichtner, J. Mater. Chem.,
21
, 17059-17062 (2011).

Z.-Z. Luo, C.-S. Lin, W.-L. Zhang, H. Zhang, Z.-Z. He and W.-D. Cheng, CrystEngComm,
16
, 2788-2794 (2014).
Rechargeable Aqueous Lithium-Ion Batteries with Molybdenum-Based Oxides As Negative Electrode Materials
Authors: Sato Yoshihiko , Yabuuchi Naoaki
Published: December 2020

Organic electrolytes used for commercial lithium-ion batteries, like EC or DMC, are flammable, often resulting in causes of fire accidents. In 1994, an aqueous lithium-ion battery using nonflammable water as electrolyte was reported for the first time, and attention has been paid for the improved safety.1 However, the conventional aqueous electrolyte solution has a narrow electrochemical window, and improvement in energy density was, therefore, needed. In recent years, highly concentrated LiTFSA (TFSA; bis(trifluoromethyl-sulfonyl)amide) aqueous solution has been proposed as aqueous electrolyte solutions with a wider electrochemical window.2,3

In this study, we report electrochemical properties of Mo-based oxides as negative electrode materials for aqueous batteries with the concentrated aqueous electrolyte, and 21 mol kg-1 LiTFSA aqueous solution was used as electrolyte. The Mo-based oxide, Li
y
Nb2/7Mo3/7O2, 4 is used as a negative electrode for aqueous lithium-ion batteries with spinel-type manganese-based oxide, Li1.05Mn1.95O4, as a positive electrode. Charge/discharge curves of full cells, consisting of Li1.05Mn1.95O4 and Li
y
Nb2/7Mo3/7O2, are shown in Figure 1. For comparison 1 M LiPF6/EC:DMC = 3/7 by volume and 21 mol g-1 LiTFSA/H2O are used as electrolyte solutions. Both cells show good cyclability at a rate of 1000 mA g-1 and are operable as 2 V-class full cells as shown in Figure 1. Capacity retention of both cells for 1000 cycle test is also shown in Figure 2, and the full cell with the concentrated aqueous electrolyte shows comparable reversibility with aprotic electrolyte solution with similar Coulombic efficiently.

From these results, we will further discuss the possibility of Mo-based oxide as potential negative electrode materials for aqueous lithium-ion batteries.

References

(1)Wu Li, J. R. Dahn, D. S. Wainwright, Science, 264, 1115 (1994).

(2)Suo, L. et al., Science
350, 938 (2015).

(3)Yamada. et al., Nat. Energy, 1, 16129 (2016).

(4)Hoshino et al., and N. Yabuuchi, ACS Energy Lett., 2, 733 (2017).

Figure 1
R-F Sputtered Ultrathin Organic/Inorganic Bilayer for Dendrite Free Li Deposition
Authors: Pathak Rajesh , Chen Ke , Qiao Qiquan , Zhou Yue
Published: December 2020

Lithium metal anodes have attracted great attention due to its high theoretical capacity and low redox potential. However, the notorious reactivity, uncontrolled solid electrolyte interphase (SEI) and undesired results in low battery performance and risk for safety concern. To resolve these problems, radio frequency (R-F) sputtered ultrathin bilayer of graphite and SiO2 ultrathin bilayer on a Li metal was demonstrated, for the first time, as an effective SEI layer. The graphite-SiO2 bilayer modified Li anode showed an improved capacity retention of 98.57% for lithium nickel cobalt manganese oxide cathode (NMC111) and 96.78% for lithium titanate (LTO), compared to bare Li anodes at 82.73% (NMC111) and 92.31% (LTO), respectively. Higher capacity, longer cycling stability and lower voltage hysteresis were obtained with the use of the graphite and SiO2 modified Li anode. Graphite acts as an electrical bridge between the plated Li and Li electrode, which lowers the impedance and buffers the volume expansion during Li plating/stripping. The addition of an ultrathin SiO2 layer facilitates Li diffusion and lithiation/delithiation, provides higher electrolyte affinity, higher chemical stability, and higher Young’s modulus to suppress the Li dendrite growth. This novel technique can open further pathways towards practical realization of use of lithium metal battery (LMB) in high energy density battery technologies such as Li-S and Li-air battery.
Effect of Different Hydroxyapatite Coating on Photocatalytic Characteristics of Titanium Dioxide Photoanode
Authors: Nay Wunn Htoo , Sakamoto Yutaro , Motoda Shinichi , Morita Motoaki
Published: December 2020

The photocatalytic n-type semiconductor characteristics of titanium dioxide (TiO2) has been under study for decades. We have studied the photocatalytic effect of titanium dioxide electrode such as the effect of impurities on TiO2, and the effect of heat treatment on TiO2. We also have studied the effect of dye sensitizing on TiO2 electrode with seawater as the electrolyte. In that study, we found that the hydroxyapatite (HAp) coating used for the purpose to increase the binding ability between dye and TiO2 improved the capability of TiO2 electrode. In order to clearly know the mechanism of HAp coating and to improve the effect of HAp coating on TiO2 electrode, this study is conducted by preparing different types of HAp paste for coating on TiO2 electrode.

Screen printing method was used for TiO2 layer and both manual and screen printings were used for HAp (Ca10(PO4)6(OH)2) coating for comparison. Type 329J4L stainless steel was used as a substrate for TiO2 electrode. The surface of the substrate was cleaned with ultrasonic cleaner and then the surface was passivated with HNO3 solution for 30 minutes. Double layers of TiO2 were screen printed on the substrate. The first layer was screen printed and heat treated at 150 ºC for 60 minutes. The second one after printed was heat treated at 550 ºC for 30 minutes. HAp was coated on TiO2 doubled layer. HAp paste was heat treated after printed. HAp paste was prepared from HAp powder. The powder was mixed with carboxymethyl cellulose (CMC) in various ratios. Water and alcohols are added to the mixture and well stirred to get a paste. Different types of HAp paste were prepared by changing the ratios of the constituents of the paste. The finishing was performed to get the electrodes ready for measurements in artificial seawater.

The potential measurement, polarization and power density measurements against platinum counter electrode were performed by a potentiostat in dark and irradiated conditions. The irradiation used for the experiments is a xenon lamp with 150 W and calibrated wavelength range from 250 nm to 800 nm. The lamp was calibrated so that the light intensity produced became approximately 10.5 mW/cm2. The surfaces of the electrodes before and after measurement were analysed and the microstructures of the electrodes were compared by scanning electron microscope (SEM). The photocatalytic effects of HAp were observed but the cause is still unclear. The study showed that screen printing of HAp on TiO2 electrode showed higher photopotentials than manual printing or without printing. The variations in HAp paste constituents also affected the performance of TiO2 electrodes. The power density output of TiO2 can be increased more than 2 times with HAp coating. Removal of HAp particles from the electrode surfaces were observed. Further study on new techniques for HAp paste preparation and film forming process is suggested.
The Study of Synthesis Mechanism of Poly-Neutral Red and Its Electrocatalytic Property
Authors: Huang Xin , Harada Yuya , Nishiumi Nobuyuki , Coskun Halime , Aljabour Abdalaziz , Stadler Philipp , Konno Ryuto , Shiroishi Hidenobu , Yoshida Tsukasa
Published: December 2020

１．
Intention

Concentration of carbon dioxide (CO2) in the atmosphere has steadily increased since industrial revolution. Despite the recent significant cost reduction of renewable electricity by solar and wind, their intermittency hinders the total shift to renewable energy. It is urgently needed to develop technologies for fast conversion of electrical energy into storable chemical energy by electrolysis, e.g., by water splitting and CO2 reduction. Stable and high-performance electrocatalysts are essential but must be developed without depending on precious metals for the real use and sustainability of the technology. Recently, we have demonstrated high and stable electrocatalytic properties of conductive organic polymers, such as polydopamine (PDA) and polyguanine (PGA) for hydrogen evolution reaction (HER) and CO2 reduction reaction (CO2RR)1,2). Hydrogen bonding N and O atoms introduced to these polymers are expected to stabilize the reaction intermediates for their high catalytic activities. In this study, a phenazine dye, neutral red (NR) was employed as the monomer to obtain a metal-free catalyst. NR bears many amino functions to make it electropolymerizable just like poly-aniline (electropolymerization deposition, to be called EPD). Also, oxidative chemical vapor deposition (oCVD) was employed to obtain PNR. Synthesis, characterization and comparison of the catalytic activities of PNR by EPD and oCVD are discussed.

２．
Experiment

EPD of PNR onto carbon felt (CF) was carried out by cycling potential between -1 and +1 V vs. Ag/AgCl for 100 cycles in an aqueous solution containing 0.2 mmol/L NR and 0.5 mol/L KNO3 (pH 5) at 50 mV/s. oCVD of PNR was performed in a three-zone quartz tube furnace under N2 flow, while setting the temperature for NR, sulfuric acid and CF at 375, 220 and 100ºC, respectively, for 240 min. PNR-modified as well as bare CF electrodes were measured under N2 and CO2 in a 1 M KNO3 (pH 7) for their catalytic activities for HER and CO2RR.

３．
Result

While bare carbon felt (CF) electrode does not show any catalytic activity towards CO2RR, showing about -3 mA cm-2 current at –1 V vs. Ag/AgCl, supposedly dominated by that for HER, the PNR coated CFs show enhanced current (Fig. 1a). That by EPD gives about -5 and -6 mA under N2 and CO2, respectively, indicating its moderate catalytic activity for HER and CO2RR. PNR prepared by oCVD, on the other hand, gives -6 and -12 mA, to demonstrate its superior activity, especially for CO2RR. Chronoamperogram measured during long term electrolysis for 17 h at the oCVD PNR electrode indicates reasonable stability of the catalysis (Fig 1b). These results already nicely confirm catalytic activity of PNR for its conductivity and hydrogen-bonding ability.

H. Coskun et al., Sci. Adv. 3, e1700686 (2017).

H. Coskun et al., Adv. Mater. Interf.
10, 1901364 (2019).

Figure 1
Time-Domain Thermoreflectance Study on Superlattice-like Phase Changing Chalcogenide Materials
Authors: Choi Seok , Yun Hee Ju , Choi Byung Joon
Published: December 2020

Phase change memory (PCM) has been developed as one of the next generation memory candidates due to its high read/write speeds, high densities, and non-volatile characteristics. This memory uses the phase change of the chalcogenide materials by Joule heating. However, there is a problem of requesting high reset current, thereby increasing power consumption during melt-quench process for its amorphization. As a way to solve the high reset current, interfacial PCM (iPCM) was suggested. It is based on the metastable states formed in superlattice-like GeTe/Sb2Te3 stack of high quality. This PCM operates with a reversible structural change between high and low resistance states without melt-quench process. However, if the heating from electrode is too excessive during the iPCM operation process, unwanted melting can occur and iPCM characteristics can be lost. Therefore, it is necessary to study the thermal effects of superlattice-like phase change material and electrode in order to ensure stability in conventional PCM or iPCM operation.

In this study, we conduct time-domain thermoreflectance study on the molecular-beam-epitaxially grown phase change materials; GeTe and Sb2Te3. Phase change layer was consisted of single or superlattice-like structure. TiN metal layer was used to see the thermal boundary resistance between the metal and phase change materials. Au metal layer was deposited as a photothermal transducer layer due to its stability and thermoreflectance coefficient value. Thermal conductivities of signle and superlattice-like thin films are compared to analyze the thermal effects. In addtion, heat conduction between the metallic TiN and phase change material of high quality is considered.
Sodium Hydroxide Assisted Work Function Tuning of Hole Transport Material for Efficient Wide-Bandgap Perovskite Solar Cells
Authors: Laskar Md Ashiqur Rahman , Qiao Qiquan (Quinn)
Published: December 2020

Poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) is widely used as hole transport material (HTM) in perovskite solar cells (PSC) of inverted structure. However, suitable energy level alignment between the Perovskite material and PEDOT.PSS is very important for proper charge transportation. Perovskite materials at various compositions of organic-inorganic compounds usually have different energy levels. Therefore, it is essential to tune the energy level hence the work function of PEDOT:PSS material to fulfill the requirement. In this work, 0.1 M sodium hydroxide (NaOH) is employed to modify the work function (Φ) of PEDOT:PSS HTM in MA0.9Cs0.1Pb(I0.6Br0.4)3 based wide-bandgap (1.82 eV) perovskite solar cells. Kelvin probe force microscopy (KPFM) confirms that Φ of the HTM gradually increases with the addition of very small amount of NaOH. An increase of Φ indicates that highest occupied molecular orbital (HOMO) level of HTM is getting closer to the HOMO of perovskite material which is beneficial for photogenerated hole extraction. Quenching of perovskite emission spectra in steady state photoluminescence (PL) spectroscopy also supports this enhanced hole extraction. Essentially, the optimum amount of NaOH needs to be added as higher amount can adversely affect the electrical conductivity of PEDOT:PSS. Besides, added NaOH provides Na+ ions in PEDOT:PSS which transforms some acidic PSS-H into neutral PSS-Na causing retardation of counter-ion exchange at perovskite and HTM interface. This helps to reduce the potential energy loss in the interface. Consequently, the final power conversion efficiency of the PSC is increased from 10.92% to 12.97% through the improvement of all performance related parameters such as short circuit current density (Jsc
), open circuit voltage (Voc) and fill factor (FF). In addition, similar characteristics X-ray diffraction (XRD) peaks reveal that NaOH treatment in HTM does not affect the regular crystallization of MA0.9Cs0.1Pb(I0.6Br0.4)3 perovskite.
The Impacts of Cesl and STI Mechanical Stress Effect on Device Performance for UTBB FD-SOI MOSFET
Authors: Yun Byung-eun , Hong Yk , Jung Young-sang , Kim Youngmok , Park Jin-Hong , Kang Kyung-Lyong , Kang Jun-Gu , Kim Jong-Ho
Published: December 2020

The effects of a stressor nitride oxide layer on device performance and reliability are investigated. Impact of tensile and compressive stress contact etch stop layer (CESL) and shallow trench isolation(STI) mechanical stress on performance and mobility enhancement of <110>/(100) Fully Depleted Sillicon On Insulator(FD-SOI) MOSFETs (ultrathin film, short length, metal-gate/high-K stack, thin BOX) were studied in detail. By thoroughly evaluating their impact on current, mobility, and threshold voltage, the performance gain of CESL is quantified at CMOS with mobility enhancement identified as the major source. It is also experimentally demonstrated that advantageous Length of Diffusion. In the Compress CESL(cCESL) strain , PMOS show 34% performance enhancement with LOD increase 0.1nm to 1um. On the ather hand, NMOS show 3.41%. In the Tensile CESL(tCESL) strain , NMOS show 11.72% performance enhancement with same LOD condition. On the ather hand , PMOS has changed 3.72%.