bluuebunny/crossref_metadata_2025 huggingface dataset:
Biosynthetic Electronic Interfaces for Bridging Microbial and Inorganic Electron Transfer
Authors: Hsu Huan Hsuan , Hsu Huan Hsuan
Published: May 2020

Electron transport in biological and inorganic systems is mediated through distinct mechanisms and pathways. Their fundamental mismatch in structural and thermodynamic properties has imposed significant challenge on the effective coupling at the biotic/abiotic interface, which is central to the design and development of bioelectronic devices and their translation towards various engineering applications. Using electrochemically active bacteria, such as G. sulfurreducens, as a model system, here we report a bottom-up, bio-synthetic approach to synergize the electron transport and significantly enhance the coupling at the heterogeneous junction. In particular, graphene oxide was exploited as the respiratory electron acceptors, which can be directly reduced by G. sulfurreducens through extracellular electron transfer, closely coupled with outer membrane cytochromes in electroactive conformation, and actively “wire” the redox centers to external electrical contacts. Through this strategy, the contact resistance at the biofilm-electrode interface can be effectively reduced by 90%. Furthermore, the cyclic voltammetry reveals that the electron transfer of DL-1 biofilm transformed from a low-current (~0.36 µA), rate-limited profile to a high-current (~5µA), diffusion-limited profile. These results suggested that the integration of rGO can minimize the charge transfer barriers at the biofilm-electrode interface. The more transparent contact at DL-1/electrode interface can enable unambiguous characterization of the inherent electron transport kinetics across the electroactive biofilm which can be modeled as a R(resistor) C (capacitor) circuit with critical frequency at 1000Hz. The current work represents a strategically new approach toward the seamless integration of biological and artificial electronics, which is expected to provide critical insights into the fundamentals of biological electron transport and open up new opportunities for applications in biosensing, biocomputing and bioenergy conversion.

Figure 1
Electrochemical Monitoring of Metallic Materials' Surfaces with Biofilm Formation
Authors: Kanematsu Hideyuki , Itoh Reo , Ogaki Sho , Hirai Nobumitsu , Kogo Takeshi , Ogawa Akiko , Wada Noriyuki , Tsunashima Katsuhiko , Barry Dana M.
Published: May 2020

Biofilms formed on materials by bacterial activity cause many engineering problems. It ranges from those at hospitals to toilets and kitchen at homes in various ways. To solve those problems, it is very important to analyze the phenomenon precisely and also to monitor the formation and growth process. To achieve the purpose, we have had many proposals for biofilm sensors so far. However, there are not so many proposals for rapid, easy and industrial biofilm sensors. In this research, we established the electrochemical system to monitor biofilm formation and growth to measure the equilibrium (static) potential and also dynamic polarization curves of metallic materials. And we discussed on how we should apply the results to evaluate biofilms on metallic materials.

We used pure copper, titanium, iron and their alloys as specimen. The lead wire was attached to the tiny coupons (10mm x 10mm) and only the opposite side was exposed as electrode. Specimens (working electrode), helical platinum wire (counter electrode) and silver/silver chloride glass electrode in 3.3M KCl solution (reference electrode) were immersed into LB culture with E.coli (K-12, G6). And those three electrodes were connected to a potentiostat. The static potential change and polarization curves in the solution were measured, while the bacterial growth and biofilm formation/growth were going on.

The equilibrium potentials for copper, iron and their alloys were shifted in less noble direction, while those of titanium and their alloys did not change and were almost constant. And the polarization curves were also reflected correspondingly. Those changes were discussed and they could be explained by the biofilm formation and growth.
ECL Array and LC-MS Studies of Nitrosamine-Metabolite-Mediated DNA Oxidation
Authors: Thiruwana Kankanamage Rumasha Nipuni , Ghosh Abhisek Brata , Jiang Di , Gkika Karmel , Keyes Tia E. , Achola Laura , Suib Steven , Rusling James F.
Published: May 2020

Metabolites of nitrosamines in cigarette smoke and E-cigarette (E-cig) vapor cause DNA damage that has been projected to lead to cancers in “genotoxic” pathways. DNA oxidation can also be mediated by reactive oxygen species (ROS) generated from redox cycling reactions involving nitrosamine metabolites, metal ions (Cu2+) and NADPH. DNA adducts of tobacco nitrosamines, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and N-nitrosonornicotine (NNN) are well known tobacco-related biomarkers, but only a few reports implicate NNK and NNN in DNA oxidation. We used electrochemiluminescent (ECL) arrays and LC-MS to explore pathways of DNA oxidation driven by metabolites of NNK and NNN facilitated by Cu2+ and NADPH which are present in significant amounts in lung tissue. We used a 3-D printed microfluidic array that first makes reactive metabolites of test compounds using metabolic enzymes (mostly cyt P450s) and DNA in thin films. The assay measurement step detects DNA oxidation selectively by ECL using a new ECL dye, [Os(tpy-benz-COOH)2]2+ that is highly sensitive for primary DNA oxidation product 8-oxodG, which serves as a co-reactant in the ECL generation. Array results reveal that NNK and NNN oxidize DNA at relatively high rates. DNA/metabolic enzyme films on magnetic beads were utilized with nitrosamines, Cu2+, and NADPH for measurement of 8-oxodG in oxidized DNA by LC-MS/MS and specific ROS involved were identified by ROS-specific assays, that showed that nitrosamines metabolism in the presence of Cu2+ and NADPH produces hydroxyl radical (•OH), singlet oxygen (1O2), and hydrogen peroxide (H2O2). Possible reactive metabolites of NNK and NNN involved in ROS generation were identified by LC-MS/MS. Results provide insight into mechanistic pathways of cyt P450-mediated metabolism of NNK and NNN in ROS production and oxidation of DNA.
Ultra-Sensitive Detection of Prostate Cancer Biomarkers Using Electron Transfer Rate Enhancement
Authors: DhanapalaMudiyanselage Lasangi , Rusling James F. , Jones Abby L
Published: May 2020

By 2019, one in every 5 men diagnosed with cancer carry prostate malignancy. Despite being the most frequent form of cancer among American men, prostate cancer still lacks proper diagnostic tools to identify indolent and aggressive forms. Drawbacks in current screening methods such as Prostate Specific Antigen (PSA) test and Digital Rectal Exam have led to over diagnosis and over treatment of prostate cancer, adversely affecting the patient’s quality of life. Herein, we report a simple, inexpensive electrochemical immunoarray for multiplexed detection of a panel of prostate cancer biomarkers, Prostate Specific Antigen (PSA), Vascular Endothelial Growth Factor-D (VEGF-D), Gene fusion proteins ETS related gene(ERG) and Insulin-like Growth Factor-1(IGF-1) that we have verified as providing a more accurate diagnosis of the type of prostate cancer than PSA test alone. The sensor features an array of eight screen printed carbon electrodes (diameter ~700 μm) coated with a layer of 5 nm Au nanoparticles and immobilized with antibodies to capture analytes. After sample introduction and analyte binding, a mixture of poly-horseradish peroxidase (HRP)-labeled detection antibodies are delivered, followed by hydroquinone (HQ) mediator to facilitate amperometric detection. Dual amplification by H2O2-driven oxidation of each of the 400 HRPs iron hemes in poly-HRP labels to Fe=O for amperometric reduction using electron transfer catalysis by HQ along with careful optimization of antibody levels enabled ultra-sensitive detection of the biomarkers with limits of detection (LOD) at ag mL-1 levels with up to 6 log-decades dynamic range. Immunoarray analyses of sera from patients who have undergone prostatectomy and may have very low levels of these biomarkers was explored as a possible test for recurrence of prostate cancer after surgery.
Parametrization of Lithium Ion Intercalation in Graphite for Battery Modelling
Authors: Rahe Christiane , Sauer Dirk Uwe , Figgemeier Egbert
Published: May 2020

Germany currently strives for CO2-free mobility for which electro mobility will be of major importance. For a good acceptance of the technology, electro mobility must be reliable and destinations at medium distances must be reachable. Both requirements presuppose precise range predictions and precise estimations of the battery status. The precision of both calculations relies on how adequate the underlying battery model represents the internal processes of a battery cell. This contribution examines the intercalation speed of lithium ions into the graphite anode in a physical-chemical battery model as main limiting parameter for fast charging due to the risk of plating. To minimize the risk of plating the intercalation process has to be fast enough to avoid large overpotentials. In the study described in this contribution, an optical-cell is used to analyze and understand the main characteristic parameters of the graphite material and further on these results are compared to the behavior of anode materials of commercial cells. Especially the reintercalation process of lithium ions of the anode overhang back in the active part of the anode is examined over time in commercial cells. The grain size as one of the main influencing parameters is already part of the model and is an important factor here. The measurement results of the setup are compared to the electrical data of the tested cell. Plating tests have already been performed and the plating has been confirmed with electrical measuring methods and laser microscope images. This submission looks into how the material and structural parameters of the graphite influence the intercalation speed of the lithium. Thus, an optimization route towards material design for fast charging can be deducted. These results help to gain a battery model that is based on battery material properties.
Lipids Lay Thyselves Down: Redox-Induced Lipid Vesicle Fusion Onto Ferrocene-Terminated Self-Assembled Monolayers
Authors: Hmam Ons , Badia Antonella
Published: May 2020

Due to the attractive electrochemical properties of ferrocene (fast electron transfer, low oxidation potential, and two stable redox states), ferrocenylalkanethiolates on gold are the most studied and employed electroactive self-assembled monolayer (SAM) system. Oxidation of the SAM-confined ferrocenes to ferroceniums is accompanied by the formation of ion-pairs with counter-ions in solution [1,2].

Ferrocene-terminated SAMs exhibit a reversible electrochemistry in the presence of anionic surfactants such as n-alkyl sulfates and sulfonates, while the less chaotropic n-alkyl phosphates and carboxylates lead to the irreversible oxidation of the SAM-confined ferrocene (Fig. A) [3]. Cyclic voltammetry indicates that these latter surfactants form strong ion pairs with the oxidized ferroceniums; an oxidation peak is observed for the first anodic potential sweep but no reduction peak is detected during the reverse sweep. No redox peaks are observed in subsequent sweeps. The surface plasmon resonance signal does not return back to its original value during reduction, indicating an irreversible adsorption of material to the surface, which in turn suggests the formation of a stable and insoluble ferrocenium-surfactant anion complex or deposit that blocks the redox process. In this work, atomic force microscopy is used to investigate the association of sodium n-dodecanoate to the SAM surface.

This electrochemical approach appears to be an effective strategy for triggering the formation of solid-supported lipid membranes by the fusion of phospholipid vesicles onto the ferrocenylalkanethiolate SAM. In fact, phospholipids are double-tailed amphiphiles and these can associate with the oxidized ferrocene (Fig. B). A potential-step hold at 0,64 V for only five minutes induces the immediate adsorption of phosphatidylserine (DMPS, POPS and DOPS) at the SAM-gold/electrolyte interface with a full surface coverage. This technique is a versatile tool that offers many benefits such as, a faster supported lipid bilayers formation mimicking the biological membranes, a larger variety of lipid composition, structure and chemical nature, and a possibility of using metal surfaces considering their potential applications in electrochemical techniques, spectroscopic techniques and surface plasmon resonance. In this work, AFM-based nano-shaving, force spectroscopy, and surface plasmon resonance are combined to determine the thickness of the obtained lipid membrane.

References

[1] E. Dionne, T. Sultana and A. Badia, J. Am. Chem. Soc.
135, 17457-17468 (2013).

[2] E. Dionne and A. Badia, ACS Appl. Mater. Interfaces
9, 5607-5621 (2017).

[3] A. Salis and B. W. Ninham, Chem. Soc. Rev.
43, 7358-7377 (2014).

Figure 1
Utilizing Band Diagrams to Interpret the Photovoltage and Photocurrent in Photoanodes: A Semiclassical Device Modeling Study
Authors: Miao Botong , Iqbal Asif , Bevan Kirk H
Published: May 2020

Photoelectrochemcial (PEC) cells offer a promising route for supplying the world’s population with sufficient energy in an environmentally friendly manner. However, inefficiency remains a major bottleneck towards the large-scale commercialization of PEC cells. The photovoltage and photocurrent serve as important design metrics when assessing the efficiency of photoanodes within PEC cells. However, to date wide disagreement persists regarding how the photovoltage should be physically interpreted; this lack of consensus is further coupled to physical interpretations of the photocurrent. In this work, we utilize state-of-the-art device modeling to help clarify the physical origins of both the photovoltage and photocurrent in photoanodes. Through a systematic examination of a model photoanode (hematite), we correlate directly measurable current-voltage characteristics with operational band diagrams. It is shown that by directly mapping specific operating points of either equal current or equal voltage (both illuminated and in the dark) to band diagram plots, one is able to obtain substantial insights regarding the physical nature of both the photocurrent and photovoltage. By aiding the community wide effort to arrive at a consensus on these concepts, we aim to further enable the design of higher efficiency photoanodes.
A Pure Titania Photocatalyst: Preparation, Characterization and Photocatalytic Activity of Octahedral-Shaped Anatase Particles
Authors: Ohtani Bunsho , Li Yumin , Takashima Mai
Published: May 2020

Different from organic molecules and metal complexes, which can be identified by chemical composition and structural characteristics such as NMR spectra, inorganic solid materials especially metal oxides cannot be identified, i.e., their purity cannot be evaluated in a strict scientific sense, because at least three structural parameters, bulk structure, surface structure and bulk/surface size, must be determined. However, in the other words, solid metal-oxide samples can be assigned to be "pure", if their three parameters are determined, by macroscopic measurements, to be uniform. Here, attempts to prepare octahedral-shaped anatase titanium(IV) oxide (titania) particles (OAPs) of uniform bulk structure (anatase with negligible non-crystalline components), surface structure (only exposing {101} facets) and particle size are reported as the first and sole example of a "pure" metal-oxide powder. In this study, OAP samples were prepared by sonication-hydrothermal (HT) reaction of potassium-titanate nanowires. Characterization of the samples by Rietveld analysis of XRD patterns, reversed double-beam photoacoustic spectroscopy and SEM observations revealed the homogeneousness of crystalline bulk, surface and particle size, respectively, to indicate the samples "pure".
Design of a Reference Model for Fast Optimization of Photo-Electrochemical Cells
Authors: Tenholt Carmen , Klassen Thomas , Schieda Mauricio
Published: May 2020

The photo-electrochemical (PEC) cell, which combines the technology of electrolyzers and photovoltaics, is a promising candidate for the electrolysis of hydrogen with reduced external energy supply. Multiple parameters of such cells have to be adjusted to achieve the most efficient assembly for given requirements. These parameters include the choice of photoactive material, type and kinetics of electrolyte and the cell geometry, which finally determine the photocurrent. As the dependency between these parameters and the cell performance is complex, numerical simulations are an indispensable tool for the optimization process. To guarantee a reliable reference model that applies for all possible parameter changes, iterative verification with experiments is necessary. Especially the precise modelling of the interfaces between photoactive substrate and electrolyte poses a significant challenge for the numerical simulations. Nevertheless, precise modelling of this region is crucial, as it largely determines the cell efficiency by controlling the reaction rate, gas saturation, electrode corrosion and thus the photocurrent. In this work we present results of numerical modelling of PEC cells with COMSOL Multiphysics, their benchmarking with experimental data measured with varying 3D-printed geometries, electrode substrates and electrolyte compositions as well as new approaches for optimizing the efficiency of PEC cells.
Selective Electrochemical Detection of Nitrite Using Cobalt Phthalocyanine Modified on Multi-Wall Carbon Nanotubes
Authors: Lu Shun , Hummel Matthew , Gu Zhengrong
Published: May 2020

Nitrite (NO2
-) as an important preservative is extensively used in the food industry, especially in the production and processing of pickled meat due to nitrite prevents bacterial growth. In addition, NO2
- as a toxic contaminant probably threaten human health by producing N-nitrosamines with highly carcinogenic. U.S. Environmental Protection Agency has restricted the maximum contaminant level to 1.0 ppm (21.7 μM), and a similar guideline value recommended by WHO is 3.0 ppm. European Union Scientific Committee for Food sets the acceptable daily intake (ADI) of NO2
- as 0.06 mg kg-1 of body weight. Voltammetric biosensing is considered the most promising approach because it offers a fast, reliable, and low-cost detection. In this abstract, cobalt (II) phthalocyanine (CoPc) was immobilized on multi-wall carbon nanotubes (MWCNTs), then modified on glassy carbon electrode (GCE) as an electrochemical senor toward nitrite using the voltammetric technique. Consequently, we developed a facile, sensitive, and rapid electrochemical method for nitrite determination, which reached a linear dynamic range of 0.01 to 1050.0 mM with a detection limit of 2.11 μM. The simple preparation of CoPc/MWCNTs makes the novel material convenient tools for the development of new electrode modified materials. Such excellent performance is ascribed to the synergistic effect between CoPc and MWCNT, indicating the promise of applying CoPc/MWCNTs@GCE in the practical bio-sensing applications.

Figure 1
Cross-Linked Binders with Metallic Ions for Si-Based Electrodes in Li-Ion Batteries
Authors: Huet Lucas , Roué Lionel , Lestriez Bernard , Devic Thomas
Published: May 2020

Silicon is a very promising anode material for Li-ion batteries due to its much higher storage capacity than graphite [1]. However, its huge volume expansion upon lithiation induces major mechanical degradation of the electrode, resulting in a poor cycle life. In this context, the optimization of the binder properties used for the electrode processing is crucial. In the present work, the impact of the addition of metallic ions (e.g. Zn2+) in the electrode formulation, likely to chemically crosslink carboxylate groups of the binder (e.g. carboxymethyl cellulose) is studied. The formation of COO-metal coordination bonds is confirmed from IR spectroscopy analyses and its impact on the rheological properties of the ink, the mechanical strength of the coating and the electrochemical performance of the electrode is highlighted. This approach, with the myriad of possibilities of coordination chemistry, opens very interesting prospects for designing a novel class of smart binders for lithium-ion batteries.

[1] M.N. Obrovac, V.L. Chevrier, Alloy Negative Electrodes for Li-Ion Batteries. Chem. Rev. 2014, 114, 11444-11502.
Morphology Control to Enable High Capacity Li-Rich Disordered Rock Salt Cathodes
Authors: Chung Hyeseung , Doux Jean-Marie , Grenier Antonin , Meija Carlos , Sayahpour Baharak , Meng Ying Shirley
Published: May 2020

Li-rich disordered rock salt (DRS) oxides are a promising class of cathode materials with the wide chemical space to be explored. The high capacity (>300mAh/g) of this class of material can be explained by the reversible redox chemistry of the oxide anions, which sets it apart from the conventional layered cathode materials that rely only on the transition metal redox. However, these materials suffer from poor ionic and electronic transport properties: Most previous studies report electrochemical performance at low current rate and elevated temperature. Even then, the particle size needs to be reduced to sub-micrometer size, often by high-energy ball milling, to get reasonable capacities.

To mitigate this issue, we performed a detailed study of the synthesis of three different Nb-based Li-rich DRS materials - Li3NbO4, Li1.3Fe0.4Nb0.3O2, and Li1.3Mn0.4Nb0.3O2. Systematic evaluation shows that both the synthesis conditions and the reagents used have a large effect on the phase and morphology of the material synthetized, and therefore on its electrochemical performance. Without varying the synthesis method, the extent of cation ordering, the particle morphology, and the degree of elemental segregation can be controlled by a careful choice of the metal oxide precursors. This study helps the community to distinguish important synthesis criteria in order to design Li-rich DRS cathode materials with improved electrochemical performance.
A Diffusion-Reaction Mechanism Promoting Spherical Li Deposition
Authors: Chen Xiaoru
Published: May 2020

Li metal is recognized one of the most promising anode materials owing to its ultrahigh theoretical specific capacity of 3860 mAh cm−2 and lowest electrochemical potential of −3.04 V vs. standard hydrogen electrode. Nonetheless, Li metal anode has been dramatically hindered from practical application by the dendritic Li growth. Regulating the Li deposition into spherical is an effective approach to avoid issues caused by Li dendrites, where the mechanism of forming spherical deposition is unknown. In this contribution, a diffusion-reaction competition mechanism is prospected to reveal the “truth” of spherical Li deposition. Based on the model experiment date through controlling the Li ion diffusion and reaction step, Li deposition morphology map is gained to verify that the diffusion and reaction step synergistic determine the ion concentration beneath the SEI and therefore regulate the Li deposition morphology. This study provides further fundamental understanding of Li plating and directly promotes safe Li metal battery design to benefit future wireless and fuel-free world.

Figure 1
Highly Stable Passivation Layer on Metallic Lithium for High-Energy Rechargeable Batteries
Authors: Joraleechanchai Nattanon , Duangdangchote Salatan , Donthongkwa Ruttiyakorn , Krittayavathananon Atiweena , Sawangphruk Montree
Published: May 2020

Lithium metal is an attractive anode material for rechargeable batteries due to its extremely high theoretical specific capacity (3860 mA h g−1), low density (0.59 g cm−3) and highest negative reduction potential (−3.040 V vs. S.H.E.). Unfortunately, lithium metal itself faces many problems including inhomogeneous lithium deposition, infinite volume expansion, increased polarization, and dendrite formation. To overcome these drawbacks, several methods have been studied such as the use of an artificial solid electrolyte interphase (SEI) layer, and electrolyte additives. However, the electrolyte additives are continuously consumed during cycling and thus affect the electrochemical performance. Herein, we use the imidazolium-based ionic liquid in order to passivate the metallic lithium. This can lead to the stable and uniform SEI formation through Li stripping and plating. To achieve fundamental understanding, reactive molecular dynamic simulation (Reaxff) has been used to investigate the mechanism and compositions of the passivation layer compounds. The predicted compounds relate and even control to the cell performances of Li metal batteries.
Observation of Lithium Dendrite Growth on Llzo-PEO Solid Electrolyte
Authors: Bunyanidhi Panyawee , Phattharasupakun Nutthaphon , Duangdangchote Salatan , Krittayavathananon Atiweena , Sawangphruk Montree
Published: May 2020

Solid-state electrolytes have been discovered as an alternative to liquid electrolyte on lithium-based batteries. Among all solid electrolytes, poly (ethylene oxide) based-solid electrolytes (PEO) have the advantages of low flammability, good flexibility, and excellent thermal stability. The major problem limiting the rate capability of PEO-based electrolyte in the lithium metal battery during charging is the issue of lithium penetration through the PEO electrolyte that results in short circuits 1. To overcome these drawbacks, we have added the ceramic fillers (i.e., garnet (Li7La3Zr2O12) etc.) in a ratio of 10-40% in the polymer host matrix. The garnet ceramic filler contributes to reduce the crystallinity of polymer and so to increase the ionic conductivity. The ceramic in polymer also provides higher mechanical strength that can reduce the lithium dendrite formation 2. To investigate the formation of lithium dendrite, we show a detailed study of lithium metal deposition on the LLZO-PEO electrolyte using ex-situ electrochemical and electron microscopic methods.

Keywords: Solid-state lithium batteries, Solid polymer electrolyte, Garnet, Polymer-ceramic composite electrolyte, Lithium dendrite

REFERENCES

1. J. Mindemark, M. J. Lacey, T. Bowden and D. Brandell, Progress in Polymer Science, 2018, 81, 114-143.

2. W. Zhang, J. Nie, F. Li, Z. L. Wang and C. Sun, Nano Energy, 2018, 45, 413-419.

Figure 1
High Mass Loading Copper Sulfide Based Composite Cathodes for All-Solid-State Lithium Sulfur Batteries Enables High Volumetric Capacity
Authors: Hosseini Seyed milad , Ito Seitaro , Aihara Yuichi , Varzi Alberto , Passerini Stefano
Published: May 2020

The current state of the art insertion cathode materials provides energy density around 700 Wh kg-1. In order to improve the energy density of batteries, conversion type materials are considered. Among these, Sulfur is regarded as promising cathode material as it theoretically provides a high specific capacity of 1672 mAh g-1 and energy density of 2500 Wh kg-1, a value three times higher than the conventional state of the art cathode materials.[1] Unfortunately, the Sulfur conversion reaction is accompanied by 80% volume change and polysulfide shuttling[2]. The use of composite cathodes, incorporating carbonaceous materials and metal sulfides, can help improve cell performance by buffering volume changes while creating effective electron conduction pathways and enhancing sulfur utilization by catalytic effects[3]. Recently we studied the effect of different metal sulfides on the sulfur cathode and realized their beneficial effect towards improved electrochemical performance. This work shows how the synergy between CuS (a transition metal sulfide) and S can lead to extraordinary high areal capacities, improved cycling life, higher energy efficiency, and volumetric energy density compared to a pure S cathode. The all-solid-state cell using an inorganic solid-state Li2S-P2S5-LiI electrolyte, metal sulfides-containing composite cathodes, and Li metal showed stable cycling (1200 cycles over one year) with high specific capacity up to (970 mAh g-1). High mass loading (5 mg cm-2 of active material equivalent to 22 mg cm-2 of total cathode mass) cells using composite (CuS-Sulfur) electrodes deliver capacities as high as 1600 mAh g-1
(CuS+S) and 7 mAh cm-2 at 20 °C. The higher density of CuS also leads to larger volumetric capacities, up to 3900 mAh cm-3(CuS+S), thus enabling an energy density gain up to 15% with respect to a conventional Carbon-Sulfur cathode. Different technics such as ex-situ XRD, SEM, EIS and Galvanostatic cycling elucidate the metal sulfide conversion mechanism.

Figure 1
Study of Li Metal/C Paper Electrodes for Li/S Batteries By Operando Dilatometry
Authors: Fatahine Mohamed , Guay Daniel , Roué Lionel
Published: May 2020

The use of Li metal anode in rechargeable batteries such as Li-S and Li-air is challenging due to the uncontrolled formation of lithium dendrites during repeated charge/discharge cycling, which induces various issues such as cell short circuit, aggravated adverse reactions, dead Li formation, polarization increase and large volume changes, resulting in safety concerns and low coulombic efficiencies [1]. Different characterization techniques have been used to study Li metal electrode morphological changes associated with Li dendrite formation such as scanning electron microscopy, transmission electron microscopy, atomic force microscopy and optical microscopy [2]. A large part of these characterizations were performed ex situ or in situ but under static conditions (no cycling) or operando using open cell requiring none volatile electrolyte, giving limited information on the Li growth dynamics in real systems. Recently, operando synchrotron X-ray tomography has been used to visualize the morphological evolution of Li metal electrodes in various cell configurations (e.g. Li-S cell [3]). However, the limited access to beamtime at synchrotron X-ray sources and challenges with data processing (image segmentation, volume reconstruction, artefact minimization, etc.) are major drawbacks.

In the present study, a simple and low-cost method is used to monitor the electrode thickness variation associated with the Li plating/stripping process. This technique, named ‘’electrochemical dilatometry’’, consists in integrating a gap sensor or a displacement transducer within the electrochemical cell for measuring the vertical displacement of the working electrode during its cycling. It has been successfully applied for studying the volume expansion/contraction of Si-based electrodes for Li-ion batteries [4]. To the best of our knowledge, electrochemical dilatometry has never been applied to the study of Li metal electrodes. In the present study, this technique is used for studying the expansion/contraction behavior of electrodes integrating commercial porous C papers as 3D matrices for Li electrodeposition and compared to what is observed on a 2D Cu foil substrate (Figure 1).

References

[
1
] X.B. Cheng, R. Zhang, C.Z. Zhao, Q. Zhang, Toward safe lithium metal anode in rechargeable batteries: a review, Chem. Rev 117 (2017) 10403-10473.

[
2
] D. Lin, Y. Liu, Y. Cui, Reviving the lithium metal anode for high-energy batteries, Nat. Nanotechnol. 12 (2017) 194-206.

[
3
] G. Torin, G. Vaughan, R. Boucher, F. Alloin, M. Di Michiel, L. Boutafa, J.F. Colin, C. Barchasz, Multiscale characterization of lithium/sulfur battery coupling operando X-ray tomography and spatially-resolved diffraction, Sci. Rep. 7 (2017) 2755.

[
4
] A. Tranchot, P-X. Thivel, H. Idrissi, L. Roué, Impact of the slurry pH on the expansion/contraction behavior of silicon/carbon/carboxymethylcellulose electrodes for Li-ion batteries. J. Electrochem. Soc. 163 (2016) A1020-A1026.

Figure 1
Challenges of Nanoscale Characterisation of Litihum-Based Energy Materials
Authors: Voisard Frédéric , Brodusch Nicolas , Trudeau Michel , Zaghib Karim , Gauvin Raynald
Published: May 2020

The electric energy revolution is driven by battery technology. New chemistries and control systems enables the widespread use of portable electric devices, such as phones, computers, power tools and automobiles. The upward trend in battery performance relies on continuous research[1]. Scanning transmission electron microscopy (STEM) is a commonly used tool for nano-scale characterisation, as it allows for imaging as well as elemental and chemical analysis, when combined with energy dispersive spectroscopy (EDS) and electron energy loss spectroscopy (EELS)[2], [3]. EELS is a particularly useful technique, as the near-edge structure of the ionization edges often give chemical bonding information. However, the high energy electron beam used in STEM can damage materials[4]. This is especially problematic in the field of battery research. Low-Z elements such as lithium, carbon and oxygen, are particularly susceptible to knock-on damage[4]. Since these elements are common in lithium-ion batteries, understanding how the beam affects materials is critical to the analysis of the materials.

Commercially pure chemical compounds (LiF, LiCl, Li2CO3), acquired from MilliporeSigma, are exposed to the microscope beam, under condition favorable for EELS analysis of the Lithium K-edge. An EELS spectrometer is used to serially acquire energy loss spectra of the materials. These time-sensing series show how the near edge structure of lithium evolve as the material is damaged by the beam. In this work, the abherrent effects of the electron microscope on lithium samples is made evident.

[1] J. B. Goodenough and K.-S. Park, “The Li-Ion Rechargeable Battery: A Perspective,” Journal of the American Chemical Society, vol. 135, no. 4, pp. 1167–1176, Jan. 2013.

[2] D. B. Williams, Transmission electron microscopy: a textbook for materials science, 2nd ed. New York: Springer, 2008.

[3] J. I. Goldstein et al., Scanning Electron Microscopy and X-Ray Microanalysis a Text for Biologists, Materials Scientists, and Geologists. Boston, MA: Springer US, 1992.

[4] R. F. Egerton, “Mechanisms of radiation damage in beam-sensitive specimens, for TEM accelerating voltages between 10 and 300 kV,” Microsc. Res. Tech., vol. 75, no. 11, pp. 1550–1556, Nov. 2012.

Figure 1
Structure and Na Ion Transport in NaPF6/Carbonate Electrolyte inside Carbon Nanopores: A Molecular Dynamics Study
Authors: Park Sungwon , Fabiyi Victor Abolarin , Paek Eunsu
Published: May 2020

Sodium-ion batteries (NIBs) are in the spotlight as highly promising energy storage applications due to the low cost and wide availability of Na sources. To date, computational studies of Na storage and transport in carbon electrodes have been carried out without considering the realistic structural and dynamic properties of a carbon anode - electrolyte, which could be critical to battery performance. Using combined molecular dynamics (MD) simulation and density functional theory (DFT) calculations, we describe the behavior of a Na-based electrolyte, consisting of sodium hexafluorophosphate (NaPF6), ethylene carbonate (EC), and dimethyl carbonate (DMC), near the confined structures of nanoporous carbon electrodes. In our simulation, nanoporous carbons with an average pore size of 8.9 Å were first generated using the Mimetic porous carbon model by quench MD simulation. We also adopted the constant potential method (CPM) to model the electrode carbon to account for the fluctuation of the local charges that are characteristic of realistic battery systems. We investigated the distribution of electrolyte molecules and their microstructures at 0 V and 2 V potentials to provide molecular insights on properties such as solvent packing, degree of confinement (DoC), preferential adsorption sites, and solvation sheath structure. Under the influence of applied potential, we report a good wettability of the electrode by electrolyte molecules as a result of the interconnectivity of nanopores, with the accumulation of electrolyte compounds at the electrode/electrolyte interface as they diffuse into the nanopores. Also, Na+ intercalates into highly confined carbon structures while PF6
- occupies weakly confined carbon nanostructures by forming ion pairs with Na+. We show that nanoporous carbon structures reduce the adsorption distance of Na+ by ~29 % compared to planar electrodes and consequently identify a hydrogen-terminated edge of porous carbon as a preferential adsorption site for Na+ of favorable adsorption energy of -0.27 eV compared to the adsorption energy of 0.02 eV for Na+ insertion onto a basal surface. Finally, an investigation of the solvation sheath structure as a function of DoC shows decreased solvation shell, shortened adsorption distances, and increased counter-charge with increasing DoC.
Synthesis of Na-MnO₂ Electrodes and Its Microstructural and Electrochemical Characterization.
Authors: Cuéllar Herrera Lorena Guadalupe , Romero Serrano Jose Antonio , Estrada-Arce Elsa Miriam
Published: May 2020

The batteries are portable devices that allow to storage chemical energy and provide electric current directly. Inside the batteries, one of the most used materials is Lithium, which includes a large number of applications.

In recent years, the investigation of ion-Na and Na-MnO₂ batteries has been intensified as an alternative to Li-MnO₂ batteries. Lithium and sodium have many similar chemical characteristics and their low cost and the wide availability of sodium are factors that can make them more used in the future. An important concern in the increase of lithium battery production lies in the limited natural resources provided by this material, and its heterogeneous distribution in the earth's crust

This work is focused on the preparation of Na-MnO₂ electrodes for secondary batteries and the microstructural, structural, and electrochemical characterization of them. The synthesis technique was hydrothermal non-conventional type. The contributions are found in the comparison of the properties and electronic elements of the synthesized materials. The impact of this project is on the possible use of Na-MnO₂ electrodes as an alternative material to the one currently used in Li-MnO₂ batteries.

Figure 1
Na3Zr2Si2PO12-Polymer Hybrid Composites for Solid-State Supercapacitor Applications
Authors: Dinachandra Singh Mayanglambam , Dalvi Anshuman , Phase D M
Published: May 2020

Various Na+ ions conducting composite polymer electrolytes have been developed in last three decades, but their application is limited due to poor ionic conductivity near room temperature. Recently, we have demonstrated high ionic conductivity of ∼ 10-4 Ω-1cm-1 in NASICON-polymer hybrids and found these systems useful in energy storage applications. A high ionic mobility of ~ 10-1 cm2/V-s was also reported. Present work shows a possible application of these hybrids as electrolyte/separator in all-solid-state supercapacitor.

In this work, Na+ NASICON, viz. Na3Zr2Si2PO12 (NZSP) have been prepared by conventional solid state reaction route. Subsequently, their nanoparticles of size ~ 30 nm were obtained via mechanical ball milling. The nanoparticles were mixed with polymer in a ball mill until a homogeneous viscous slurry formation. Further the slurry was dried, hot pressed at ~ 80°C to obtain films of uniform thickness ~ 250µm. This way, composite films with composition (wt%) 10NaI-90(PEO1-xNZSPx), where 0 ≤ x ≤ 0.4, were obtained. Surface morphology, structural and thermal analysis were characterized using FESEM, XRD and DSC. A maximum ionic conductivity of ~ 4 x 10-5 Ω-1cm-1 at room temperature has been achieved for composite with x = 0.4. Impedance spectroscopy was used to understand mechanism of ionic transport. Further, to understand the role of ceramic fillers in enhancing the ionic conductivity, local structure of the composites was studied using x-ray absorption near edge structure spectroscopy (XANES) at Indus II Beamline 01, RRCAT, Indore. These results suggest a significant role of NASICON in providing pathways for Na+ ion transport.

The ionic conductivity at room temperature for composite with x = 0.4 were further modified with EMITf and EC+PC as plasticizer. A maximum ionic conductivity of ~ 2 x 10-4 Ω-1cm-1 at room temperature has been achieved with addition of 2 wt% of EMITf in the composite. To elucidate the capacity of these electrolyte as a membrane for all solid-state ionic devices, solid state super capacitors (configuration C|CPE|C) were fabricated. These composites have been found to be competitive candidates for energy storage. A maximum specific capacitance of ~ 26 F-g-1 is obtained for composite with 2 wt% EMITf at room temperature.
Ultra-High-Rate Pseudocapacitive Energy Storage in Three-Dimensional Nanoporous Gold/Silver Oxide Composites through Oxidation/Reduction of Silver(I) Oxide to Silver (III) Oxide in Non-Aqueous Electrolytes
Authors: Pröschel Alexander , Welborn Samuel S. , Fu Jintao , Detsi Eric
Published: May 2020

Charge storage in pseudocapacitive materials occurs through electron transfer (i.e. faradaic current) involving oxidation and reduction reactions. This process is usually extremely fast because the reactions take place near the surface of the material, meaning the species involved diffuse over short distances. Ionic species such as H+, OH-, Li+, and Na+ commonly used to store charge in pseudocapacitive materials are usually “foreign” elements in the materials. In this talk, I will demonstrate a pseudocapacitive charge storage approach where the ionic species is part of the material. Here we use Ag+ as the working ion in a non-aqueous electrode and silver (I) oxide grown on a three-dimensional nanoporous gold scaffold as the storage medium. Pseudocapacitive charge storage occurs through electrochemical oxidation/reduction of silver (I) oxide to silver (III) oxide at scan rates as high as 1000 mV/s. These high rates are justified by (i) the intrinsic nature of the working ion (Ag+), which is better accommodated by the host silver oxide material as opposed to foreign ions, and (ii) the excellent electronic conductivity provided by the 3D metallic scaffold current collector.
Integrating Multiple Advantages into 1 Nm Pt3Ni Bimetallic Alloy Nanowires for Oxygen Reduction Reaction
Authors: Deng Zhiping , Wang Xiaolei
Published: May 2020

Exploiting highly active and durable oxygen reduction reaction (ORR) electrocatalyst is still imperative for clean and efficient energy conversion device, such as fuel cells and metal-air batteries. For this purpose and maximize the utilization of noble Pt, we present here a facile, scalable strategy for the high-precise synthesis of 1 nm thick Pt3Ni bimetallic alloy nanowires (Pt3Ni BANWs). The seed-mediated growth mechanism of Pt3Ni BANWs is identified by examining the morphology and composition of the intermediate products collect at different reaction stages. As expected, the Pt3Ni BANWs delivered enhanced mass activity (0.546 A mg-1
Pt, exceeding the DOE 2020 target) in comparison to Pt nanowires assembly (Pt NWA, 0.098 A mg-1
Pt) and Pt/C (Pt, 0.135 A mg-1
Pt) due to the rational integration of multiple compositional and structural advantages, such as alloy feature, ultrathin 1D nanostructure and high-index facets. Moreover, the Pt3Ni BANWs displayed enhanced durability (37% MA retention) than Pt NWA and Pt after 50,000 potential cycles. All these results indicate that the ultrathin Pt3Ni BANWs are potential candidates for catalyzing ORR with acceptable activity and durability. The present work could not provide a facile strategy but also a general guidance for the design of superb performance Pt-based nanowire catalysts for ORR.

Figure 1. Progressive formation mechanism of the ultrathin Pt3Ni BANWs.

Keywords: Oxygen Reduction Reaction, Pt-Ni alloy, Nanowires, Seed-mediated growth

References:

[1] Stamenkovic, V. R.; Fowler, B.; Lucas, C. A.; Marković, N. M. Improved oxygen reduction activity on Pt3Ni (111) via increased surface site availability. Science
2007, 315, 493-497.

[2] Xiao, W.; Gong, M.; Xin, H. L.; Wang, D. Recent advances of structurally ordered intermetallic nanoparticles for electrocatalysis. ACS Catal.
2018, 8, 3237-3256.

Figure 1
Electrolyte Concentration Variation during Pulsed Potential Electrochemical CO2 reduction to Control Product Selectivity
Authors: Casebolt Rileigh , Kimura Kevin Wayne , da Silva Jessica Akemi Cimada , Kim Jiyoon , Suntivich Jin , Hanrath Tobias
Published: May 2020

One of the grand challenges in electrocatalysis is to better understand the factors that determine activity and selectivity to control the precision of electrochemical reactions.1 Electrocatalytic CO2 reduction (eCO2R) is a prototypical example of such a reaction, where control over product selectivity would completely transform electrosynthesis processes. Beyond the pursuit of fundamentally understanding electrochemical catalysis, development of eCO2R is driven by growing concerns about global CO2 emissions and the quest for valorization of captured CO2. However, product selectivity and electrocatalyst longevity persist as obstacles to broad implementation of eCO2R. One possible solution to address this challenge is to apply a pulsed potential during eCO2R, which creates a stable reduction environment and tunable product selectivity.2 We leveraged this long-term product stability of pulsed potential eCO2R to examine the relationship between electrolyte concentration and composition with product selectivity for a copper electrode. Whereas constant potential experiments suffer from quick degradation as selectivity towards CO2 reduction products lasts only on the order of one hour, pulsing the potential maintains robust selectivity over 24 hours. This stability presents a unique opportunity to vary the electrolyte parameters while keeping experimental conditions consistent thereby eliminating electrode variability. We find the relation of electrolyte concentration and composition differs greatly for constant and pulsed potential eCO2R. In the case of constant potential eCO2R, increasing KHCO3 concentration is known to favor the formation of H2 and CH4. In contrast, for pulsed potential eCO2R, H2 formation is suppressed due to the periodic adsorption of surface hydroxides, while CH4 is still favored. In the case of KCl, increasing the concentration during constant potential eCO2R does not affect product distribution, mainly producing H2 and CO. However, during pulsed potential eCO2R, increasing KCl concentration suppresses H2 evolution and greatly favors C2 products, reaching 71% Faradaic efficiency. Collectively, these results provide new mechanistic insights into pulsed potential eCO2R in context of the ionic conductivity and higher presence of surface hydroxides which promote C-C bonding. More broadly, the techniques employed here can be used to understand and optimize other electrosynthesis processes.

[1] Bell, A. T.; Gates, B. C.; Ray, D.; Thompson, M. R. Basic research needs: catalysis for energy; Pacific Northwest National Lab.(PNNL), Richland, WA (United States): 2008.

[2] Kimura, K. W.; Fritz, K. E.; Kim, J.; Suntivich, J.; Abruña, H. D.; Hanrath, T., Controlled Selectivity of CO2 Reduction on Copper by Pulsing the Electrochemical Potential. ChemSusChem
2018,
11 (11), 1781-1786.