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Refractive Index Measurement of Lithium Ion Battery Electrolyte with Etched Surface Cladding Waveguide Bragg Gratings and Cell Electrode State Monitoring by Optical Strain Sensors
摘要: In this scientific publication, a new sensor approach for status monitoring, such as state of charge and state of health, of lithium ion batteries by using special Bragg gratings inscribed into standard optical glass fibers is presented. In addition to well-known core gratings, embedded into the anode of 5 Ah lithium ion pouch cells as a strain monitoring unit, the manufacturing of a surface cladding waveguide Bragg grating sensor incorporated into the cell’s separator, that is sensitive to changes of the refractive index of the surrounding medium, is demonstrated. On the basis of the experiments carried out, characteristics of the cell behavior during standard cyclization and recognizable marks in subsequent post-mortem analyses of the cell components are shown. No negative influence on the cell performance due to the integrated sensors have been observed; however, the results show a clear correlation between fading cell capacity and changes of the interior optical signals. Additionally, with the novel photonic sensor, variations in the electrolyte characteristics are determinable as the refractive index of the solution changes at different molar compositions. Furthermore, with the manufactured battery cells, abuse tests by overcharging were conducted, and it was thereby demonstrated how internal battery sensors can derive additional information beyond conventional battery management systems to feasibly prevent catastrophic cell failures. The result of the research work is an early stage photonic sensor that combines chemical, mechanical and thermal information from inside the cell for an enhanced battery status analysis.
关键词: lithium ion,battery aging,cladding waveguide,battery electrolyte,optical sensors,battery safety,fiber Bragg grating,electrode active material,status monitoring
更新于2025-11-28 14:23:57
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Effect of electron beam irradiation on structure, morphology, and optical properties of PVDF-HFP/PEO blend polymer electrolyte films
摘要: The effect of 8 MeV energy electron beam (EB) on poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP)/poly-ethylene oxide (PEO) (@ w/w 90:10, PHP10) polymer blend films have been prepared and studied. The change in structure, morphology, and optical properties at 40, 80, and 120 kGy EB doses were investigated. The effect of the radiation process may responsible to occurs the degradation (chain scission) and chain link (cross linking) which are confirmed by the FT-IR analysis. The band at 1401 cm?1 corresponding to the –CH2– bending or scission mode have shifted to 1397 cm?1 after 120 kGy EB dose is due to the intermolecular interaction and the changes of the macromolecular chain by breaking of bonds with increased EB dose was observed. The XRD pattern shows decreased in the crystallinity from 60.03 to 23.42% and increased amorphousity for 120 kGy EB dose the and the surface morphology was drastically changed by decreasing the size of spherulites upon increased EB dose. The increase in optical absorption and the shifting of wavelength toward a higher end (red shift) was observed after the irradiation. The energy band gaps (Eg), and Urbach energy were estimated and they are found to be decreased, but the number of carbon atoms in a cluster of was increased with increased EB dose. The obtained results notice that the physical properties of polymer blend electrolytes can be improved by EB irradiation to use in different potential applications.
关键词: Polymer electrolyte,FESEM,UV–visible spectroscopy,Structural analysis,Electron beam irradiation
更新于2025-11-21 11:01:37
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Electrolyte effects on formation and properties of PEDOT-graphene oxide composites
摘要: This work presents a comparative electrochemical and spectroelectrochemical study of composites consisting of poly(3,4-ethylenedioxythiophene) (PEDOT) and graphene oxide (GO) synthesized in different electrolyte solutions. The electrochemical behavior of PEDOT/GO composites were studied in an ionic liquid (1-butyl-3-methylimidazolium tetrafluoroborate) as well as in conventional organic (acetonitrile) and aqueous electrolytes by cyclic voltammetry and electrochemical impedance spectroscopy. Additionally, we applied in situ Attenuated Total Reflection Fourier Transformed Infrared (ATR–FTIR) spectroelectrochemistry using a Kretschmann geometry cell to study the composite fabrication during potentiodynamic electropolymerization, and to study the electronic properties and charge carrier formation during p-doping. According to in situ ATR-FTIR analysis, the doping induced bands from charge carrier formation begin to grow at lower potentials for the composite film and the electronic absorptions indicate formation of only one type of charge carrier in the composite made and characterized in ionic liquid. The optical properties during doping were determined by in situ UV–Vis spectroelectrochemistry. The composite film fabricated in water has its absorbance maximum at slightly higher wavelengths, and the appearance of the film is changed from well-known light blue color of PEDOT to greyish.
关键词: spectroelectrochemistry,PEDOT,composite,graphene oxide,electrolyte
更新于2025-11-19 16:56:35
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Highly Stretchable, High‐Mobility, Free‐Standing All‐Organic Transistors Modulated by Solid‐State Elastomer Electrolytes
摘要: Highly stretchable, high-mobility, and free-standing coplanar-type all-organic transistors based on deformable solid-state elastomer electrolytes are demonstrated using ionic thermoplastic polyurethane (i-TPU), thereby showing high reliability under mechanical stimuli as well as low-voltage operation. Unlike conventional ionic dielectrics, the i-TPU electrolyte prepared herein has remarkable characteristics, i.e., a large specific capacitance of 5.5 μF cm?2, despite the low weight ratio (20 wt%) of the ionic liquid, high transparency, and even stretchability. These i-TPU-based organic transistors exhibit a mobility as high as 7.9 cm2 V?1 s?1, high bendability (Rc, radius of curvature: 7.2 mm), and good stretchability (60% tensile strain). Moreover, they are suitable for low-voltage operation (VDS = ?1.0 V, VGS = ?2.5 V). In addition, the electrical characteristics such as mobility, on-current, and threshold voltage are maintained even in the concave and convex bending state (bending tensile strain of ≈3.4%), respectively. Finally, free-standing, fully stretchable, and semi-transparent coplanar-type all-organic transistors can be fabricated by introducing a poly(3,4-ethylenedioxythiophene):polystyrene sulfonic acid layer as source/drain and gate electrodes, thus achieving low-voltage operation (VDS = ?1.5 V, VGS = ?2.5 V) and an even higher mobility of up to 17.8 cm2 V?1 s?1. Moreover, these devices withstand stretching up to 80% tensile strain.
关键词: free-standing all-organic transistors,stretchable and conformal electronics,high-mobility,elastomer electrolyte,low-voltage operation
更新于2025-11-14 17:28:48
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Enhanced optoelectronic performance of plasma electrolytic oxidized monocrystalline silicon using rGO incorporation
摘要: rGO/SiO2 composite coating was successfully prepared by plasma electrolyte oxidation (PEO) process on monocrystalline silicon (mc-Si) substrate. Investigating the effect of rGO incorporation into the SiO2 coating revealed that the addition of rGO leads to a significant increase in the photo-trapping ability due to the high specific surface area and excellent electron transfer efficiency. The PL intensity of the composite sample was found to decrease, which signified the suspension of the electron-hole pairs’ recombination. As a result, the photocurrent gain of the composite coating enhanced about 5.5 times. Likewise, the time-response switching featured an over two-fold increase for the rGO/SiO2 coating, impressively.
关键词: Semiconductors,Plasma electrolyte oxidation,Optoelectrical properties,Composite materials,rGO/SiO2 composite
更新于2025-09-23 15:23:52
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Incorporating Mn <sup>2+</sup> /Ni <sup>2+</sup> /Cu <sup>2+</sup> /Zn <sup>2+</sup> in the Co <sub/>3</sub> O <sub/>4</sub> Nanorod: To Investigate the Effect of Structural Modification in the Co <sub/>3</sub> O <sub/>4</sub> Nanorod and Its Electrochemical Performance
摘要: The major key component for developing a high-efficiency supercapacitor device is electrode and electrolyte material. This research paper demonstrates the structural modification of Co3O4 nanorod and the electrochemical behavior of Co3O4 nanorod in different aqueous electrolytes such as KOH, PVA/KOH, NaOH, KCl, and Na2SO4. The pseudocapacitive behavior of Co3O4 is varying in the order of KOH > NaOH > PVA/KOH > Na2SO4 > KCl. The storage capability of MCo2O4 (where M = Mn, Ni, Cu, and Zn) nanorods has been compared with Co3O4 nanorod in the KOH electrolyte environment. The material in the form of nanorods is beneficial for an efficient pathway to penetrate an OH- ion into the electroactive material. Among other cobaltite (MCo2O4), NiCo2O4 nanorod exhibits the outstanding capacitance value of 2041.7 F g-1 at a current density of 1 A g-1. NiCo2O4 || NiCo2O4 symmetric supercapacitor system delivers the maximum energy density of 25.42 W h kg-1 at a current density of 0.5 A g-1.
关键词: KOH electrolyte,MCo2O4 nanorod,High specific capacitance,Symmetric device
更新于2025-09-23 15:23:52
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Copper electrodeposition on silicon electrodes
摘要: A two-step process is reported for the electrochemical deposition of copper layers on n-type silicon substrates using an acidic copper sulphate solution without addition of additives and no light assistance. Metal layers were generated on electrodes with different crystal orientations. The process consists of a combination of two very common techniques: chronoamperometry and pulse plating. The former technique is applied to obtain an instantaneous nucleation on the working electrode. Therefore, a large amount of metal nuclei is formed on the substrate before the pulse technique starts. The latter is, then, used to grow the particles previously generated and form a homogeneous metal layer with full coverage onto the semiconductor electrodes. The potential magnitudes are carefully chosen in line with energy levels observed at the semiconductor-electrolyte interface and were also calculated in this work.
关键词: silicon coating,seedless electroplating,copper plating,semiconductor-electrolyte interface,pulse plating
更新于2025-09-23 15:22:29
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Effect of tantalum content on the structural properties and sensing performance of YbTaxOy electrolyte-insulator-semiconductor pH sensors
摘要: In this work, we developed YbTaxOy sensing membranes displaying super-Nernstian pH-sensitivity for use in electrolyte-insulator-semiconductor (EIS) pH sensors. We examined the effect of tantalum content on the structural properties and sensing characteristics of the YbTaxOy sensing membranes deposited through reactive co-sputtering onto Si substrates. X-ray diffraction, atomic force microscopy, secondary ion mass spectrometry, and X-ray photoelectron spectroscopy revealed the structural, morphological, depth, and chemical features, respectively, of these YbTaxOy films prepared under various Ta plasma power conditions (from 80 to 160 W). Among the tested systems, the YbTaxOy EIS device prepared at the 120 W condition exhibited the super-Nernstian sensitivity (70.24 mV/pH), the lowest hysteresis voltage (1.5 mV), and the lowest drift rate (0.26 mV/h). Presumably, this condition optimized the stoichiometry of YbTaO4 in the film and its surface roughness while reducing the crystal defect and suppressing silicate formation at the YbTaxOy-Si interface. The super-Nernstian pH-sensitivity may be attributed to the incorporation of Ta ions in the Yb2O3 forming a YbTaO4 stoichiometric film, enhancing a change in oxidation state of Yb from trivalent ion to bivalent ion and thus transferring one electron to two protons in the redox reaction.
关键词: Electrolyte-insulator-semiconductor (EIS),Sensing characteristics,Plasma power,pH sensitivity,YbTaxOy
更新于2025-09-23 15:22:29
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Probing Electrolyte Solvents at Solid/Liquid Interface Using Gap-Mode Surface-Enhanced Raman Spectroscopy
摘要: Understanding the aprotic solution structures at the immediate vicinity of solid/liquid interface (SLI) is critically important for next generation lithium ion battery development. Yet, it is still challenging to investigate the carbonate chemical profiles close to the diffuse layer (about 10 nm) of the electrical double layer at SLI due to the lack of a ultrahigh surface sensitive tool. In this work, we demonstrate the structures of commonly used carbonate solvents (ethylene carbonate (EC) and diethyl carbonate (DEC)) and a carbonate additive (fluoroethylene carbonate (FEC)) in a commercial Li-ion battery electrolyte can be determined at ~17 nm above the electrode surface. This is only enabled by a nanogap surface-enhanced Raman spectroscopy (SERS) technique based on a monolayer gold nanoparticle (Au NP) ensemble. The SERS enhancement factor (EF) of those carbonates was found to depend on the molecular polarizability, with the maximum EF at ~105 found for EC and FEC. Despite their alike chemical structures, this monolayer Au NP SERS substrate is fully capable of discrimiating the different Raman finger prints of EC and FEC. Compared to EC, several vibration modes in FEC, such as C-C skeletal deformation, ring breathing band and C=O stretching band, shift to higher frequencies because of the displacement of a hydrogen atom by a much heavier fluorine atom in a methylene bridge. This counterintuitive observation against the commonly used “ball and spring” model in vibrational spectroscopy is mostly due to the increased bond strength in the FEC ring versus that of EC. A second order empirical polynomial best describes the correlation between the SERS band integration of EC or DEC molar concentration. Our findings open up new opportunities for in-depth understanding of the electrolyte molecular vibrational behaviors at direct solid/liquid interface and developing advanced electrolytes for next generation lithium-ion batteries.
关键词: carbonate solvents,electrolyte,solid/liquid interface,lithium-ion battery,surface-enhanced Raman spectroscopy
更新于2025-09-23 15:22:29
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The role of ionic liquid breakdown in the electrochemical metallization of VO <sub/>2</sub> : An NMR study of gating mechanisms and VO <sub/>2</sub> reduction
摘要: Metallization of initially insulating VO2 via ionic liquid electrolytes, otherwise known as electrolyte gating, has recently been a topic of much interest for possible applications such as Mott transistors and memory devices. It is clear that the metallization takes place electrochemically and, in particular, there has previously been extensive evidence for the removal of small amounts of oxygen during ionic liquid gating. Hydrogen intercalation has also been proposed, but the source of the hydrogen has remained unclear. In this work, solid-state magic angle spinning NMR spectroscopy (1H, 2H, 17O and 51V) is used to investigate the thermal metal-insulator transition in VO2, before progressing to catalytically hydrogenated VO2 and electrochemically metallized VO2. In these experiments electrochemical metallization of bulk VO2 particles is shown to be associated with intercalation of hydrogen, the degree of which can be measured with quantitative 1H NMR spectroscopy. Possible sources of the hydrogen are explored, and by using a selectively deuterated ionic liquid, it is revealed that the hydrogenation is due to deprotonation of the ionic liquid; specifically, for the commonly used dialkyl-imidazolium based ionic liquids, it is the “carbene” proton which is responsible. Increasing the temperature of the electrochemistry is shown to increase the degree of hydrogenation, forming first a less hydrogenated metallic orthorhombic phase then a more hydrogenated insulating Curie-Weiss paramagnetic orthorhombic phase, both of which were also observed for catalytically hydrogenated VO2. The NMR results are supported by magnetic susceptibility measurements, which corroborate the degree of Pauli and Curie-Weiss paramagnetism. Finally, NMR spectroscopy is used to identify the presence of hydrogen in an electrolyte gated thin film of VO2, suggesting that electrolyte breakdown, proton intercalation and reactions with decomposition products within the electrolyte should not be ignored when interpreting the electronic and structural changes observed in electrochemical gating experiments.
关键词: metal-insulator transition,hydrogen intercalation,VO2,NMR spectroscopy,electrolyte gating,ionic liquid
更新于2025-09-23 15:21:21