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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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Transparent Platinum Counter Electrode Prepared by Polyol Reduction for Bifacial, Dye-Sensitized Solar Cells
摘要： Pt catalytic nanoparticles on F-doped SnO2/glass substrates were prepared by polyol reduction below 200 °C. The polyol reduction resulted in better transparency of the counter electrode and high power-conversion efficiency (PCE) of the resultant dye-sensitized solar cells (DSSCs) compared to conventional thermal reduction. The PCEs of the DSSCs with 5 μm-thick TiO2 photoanodes were 6.55% and 5.01% under front and back illumination conditions, respectively. The back/front efficiency ratio is very promising for efficient bifacial DSSCs.
关键词： dye-sensitized solar cell,platinum,bifacial,ethylene glycol,counter electrode
更新于2025-11-21 11:01:37
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Colloidally synthesized defect-rich $$\hbox {MoSe}_{2}$$ MoSe 2 nanosheets for superior catalytic activity
摘要： Transition metal dichalcogenide (TMD) nanosheets (NSs) with defect-rich and vertically aligned edges are highly advantageous for various catalytic applications. However, colloidal synthesis of defect-rich NSs with thickness variation has been a challenging task. Here, we report a colloidal synthesis of 2H-MoSe2 NSs having a large number of defects and vertically aligned edges, where the thickness is varied by changing the amount of coordinating solvent. The Se-vacancies in these NSs have introduced defect sites which are corroborated by the presence of additional vibration modes in Raman spectra. These NSs exhibit electrocatalytic hydrogen evolution reaction performances with a low overpotential (210–225 mV) at 10 mA cm?2 current density and a small Tafel slope (54–68 mV per decade). Moreover, these MoSe2 NSs are also employed as counter electrodes (CEs) for the fabrication of dye sensitized solar cells via a cost-effective and simplified procedure. The power conversion efficiencies of 7.02 ± 0.18%, comparable with Pt CE (7.84 ± 0.10%) could be routinely achieved. These results demonstrate a novel synthetic strategy to prepare layered TMDs with superior catalytic applications.
关键词： counter electrode,Transition metal dichalcogenides,dye sensitized solar cells,MoSe2 nanosheets,hydrogen evolution reaction
更新于2025-11-19 16:56:35
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Copper-Based Volumetric Filler Dedicated for Ag Paste for Depositing the Front Electrodes by Printing on Solar Si Cells
摘要： In this work we present research results on a new paste NPCuXX (where: NP—new paste, CuXX—component, XX—a modifier consisting of Ni and other important elements) based on a copper composite (CuXX) for fabrication of front electrodes in silicon solar cells. The CuXX composite is obtained by chemical processing of copper powder particles and can be used in two ways: as an additive to commercially available paste or as a base material for a new paste, NPCuXX. The CuXX offers the possibility to exchange up to 30 and 50 wt.% Ag into Cu, which significantly decreases the solar cells material costs, and therefore, the overall solar cell price. Emphasis was placed on a proper mass suitable fabrication process of the CuXX component. The NPCuXX paste has been applied both to conventional cell structures such as aluminum-back surface field (Al-BSF) and passivated emitter and rear contact (PERC), and finally solar cells with front electrodes deposited by screen-printing method were fabricated and characterized by current-voltage techniques. This paper reports the first implementation of the copper volumetric material into a screen print paste used in a high-temperature metallization process to fabricate the front contacts of Si solar cells with a highest fill factor of 77.92 and 77.69% for the abovementioned structures, respectively.
关键词： crystalline silicon solar cells,front electrode,copper-based volumetric filler
更新于2025-11-14 17:04:02
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In Situ Microwave-Assisted Fabrication of Hierarchically Arranged Metal Sulfide Counter Electrodes to Boost Stability and Efficiency of Quantum Dot-Sensitized Solar Cells
摘要： This study describes preparation of metal sulfide counter electrodes (CEs) through one-pot microwave-assisted route to improve power conversion efficiency (PCE) of quantum dot-sensitized solar cells at a lower cost. The CuS nanorods, Ni0.96S nanoparticles, and PbS nanocubes are synthesized and deposited in situ on fluorine-doped tin oxide substrate to serve as CEs without further post-treatment. Effects of several reaction parameters including sulfur precursor (Na2S, C2H5NS, CH4N2S), Cu concentration, reaction time, and choice of cation (Cu, Ni, Pb) on the CEs morphology, electrochemical characteristics, and PCE are studied. Furthermore, nanostructure formation and thin film growth are studied and correlated with PCE, from which morphology- and composition-performance relationships can be inferred. Hierarchically assembled nanorod CuS CEs exhibit higher electrochemical stability in the S2–/Sn2– redox reaction. Together with the efficient charge transfer and higher diffusion coefficient of polysulfide redox at the electrode/electrolyte interface, deduced from electrochemical impedance spectroscopy and Tafel analyses, a PCE of 8.32% is achieved for the CuS CE. The enhanced photovoltaic performance is ascribed to the 1D CuS nanorods forming a diffusive structure which decreases charge transfer impedance and facilitates regeneration of polysulfide redox leading to a higher short-circuit current density and fill factor.
关键词： In situ deposition,quantum dot-sensitized solar cells,counter electrode,CuS,microwave-assisted synthesis
更新于2025-11-14 17:04:02
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Formation of CoTe2 embedded in nitrogen-doped carbon nanotubes-grafted polyhedrons with boosted electrocatalytic properties in dye-sensitized solar cells
摘要： Developing high active and earth-abundant electrocatalysts is a challenge for commercialization of dye-sensitized solar cells (DSSCs). Herein, a designed synthesis of CoTe2 nanoparticles embedded in nitrogen-doped carbon nanotubes-grafted polyhedron (CoTe2@NCNTs) using zeolitic imidazolate framework-67 (ZIF-67) as template is reported. Benefiting from the high surface area induced by the in situ growth of CNTs and the synergistic effect between CoTe2 and the N-doped nanostructured carbon, CoTe2@NCNTs hybrids exhibit remarkable catalytic activity toward the reduction of I3? ions. When employed as counter electrode (CE) of DSSCs, CoTe2@NCNTs hybrids deliver overwhelming power conversion efficiency (PCE) of 9.02%, possessing ~12% improvement compared with the Pt CE (8.03%). This study provides an emerging substitute for traditional Pt CE and a strategy to synthesize efficient electrocatalysts via rational surface engineering.
关键词： Carbon nanotubes,Counter electrode,Dye-sensitized solar cells,Cobalt telluride
更新于2025-11-14 17:04:02
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Synthesis of CoNi bimetallic alloy nanoparticles wrapped in nitrogen-doped graphite-like carbon shells and their electrocatalytic activity when used in a counter electrode for dye-sensitized solar cells
摘要： Nanoparticles of the bimetallic alloy CoNi wrapped in nitrogen-doped graphite-like carbon shells and dispersed on nitrogen-doped graphite-like carbon sheets (CoxNi1?x@NC) were synthesized by calcining CoNi metal–organic frameworks that were prepared through a facile solvothermal reaction using various raw-material molar ratios Co:Ni and CoNi:ethylenedinitrilotetraacetic acid. After depositing CoxNi1?x@NC for use as a counter electrode film in dye-sensitized solar cells, it was found that the electrocatalytic activity of the CoxNi1?x@NC counter electrode towards triiodide reduction could be optimized by simply tuning the molar ratios (Co:Ni and CoNi:ethylenedinitrilotetraacetic acid) appropriately during CoxNi1?x@NC synthesis. Cells that utilized a CoxNi1?x@NC counter electrode exhibited strong chemical-composition-dependent photovoltaic performance. Under optimal conditions, the CoxNi1?x@NC counter electrode presented an impressive energy conversion efficiency of 3.58%, suggesting that it is a highly promising counter electrode for application in dye-sensitized solar cells. This counter electrode has the advantages that it is considerably less expensive than a Pt counter electrode and that it provides the basis for the design and preparation of other inexpensive and efficient counter electrodes to replace Pt.
关键词： Photovoltaic performance,Dye-sensitized solar cells,CoNi alloy bimetallic nanoparticles,Counter electrode,Electrocatalytic activity
更新于2025-11-14 17:04:02
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In situ synthesis of ternary nickel iron selenides with high performance applied in dye-sensitized solar cells
摘要： Comparing with the binary chalcogenides, the ternary chalcogenides may achieve higher electrical conductivity and electrochemical activity due to the synergistic effect of the different metal cations. Herein, ternary nickel iron selenide (Ni0.5Fe0.5Se2) was fabricated through a facile one-pot solvothermal method with the assistance of glucose for the first time. The dye-sensitized solar cells (DSSCs) were assembled with the as-prepared Ni0.5Fe0.5Se2 as counter electrode (CE). Electrochemical measurements indicated that the Ni0.5Fe0.5Se2 possessed small electron transfer resistance at the interface between electrode and electrolyte, great electrocatalytic activity and reaction kinetics toward the reduction of triiodide. Compared with conventional Pt CE (7.24%), the DSSCs based on Ni0.5Fe0.5Se2 CE achieved a greater power conversion efficiency of 7.89%. Furthermore, this study provides a new idea and strategy with convenient method to synthesize Pt-free alternative materials.
关键词： Counter electrode,Solvothermal method,Dye-sensitized solar cells,Ternary nickel iron selenide
更新于2025-11-14 17:04:02
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A simple method to synthesize low-cost carbon modified TiO <sub/>2</sub> counter electrodes for high-efficiency dye-sensitized solar cells
摘要： Low cost and stable counter electrodes (CE) for dye-sensitized solar cells (DSSC) are promising for widespread use. In this paper, we report a simple and effective method to synthesize carbon modified TiO2 (TiO2/C) thin film as an abundant low cost CE for high-efficiency DSSC. The TiO2 paste layer contained organic compound was deposited on FTO glass substrate by a screen-printing method. When annealing the TiO2 paste layer at 450–550 °C under Ar flow, these organic compounds are decomposed to carbon to form carbon coated TiO2 nanoparticles. When used as a CE of DSSCs, the experimental results point out that the photoelectric conversion efficiency of DSSCs was obviously improved to near that of the referenced Pt CE. For TiO2/C is one of the cheapest and most stable materials, this TiO2/C can be used as a low cost CE for large scale high efficient DSSCs.
关键词： carbon nano materials,solar energy materials,counter electrode,dye-sensitized solar cell
更新于2025-11-14 17:04:02
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Preparation of CoS<sub>2</sub> counter electrode on Ni sheet for QDSSCs via electrophoretic deposition of ZIF-67
摘要： To prepare counter electrode with low cost and high catalytic activity is a way to improve photovoltaic performance of quantum dot-sensitized solar cells. Here, ZIF-67 thin films are prepared on Ni sheet and FTO conducting glass substrate by electrophoretic deposition at different applied electric fields, and then CoS2/Ni and CoS2/FTO electrodes are obtained by vulcanizing the ZIF-67 thin films using thioacetamide. The prepared CoS2 thin films are characterized by the measurements of scanning electron microscope, X-ray photoelectron spectroscopy, X-ray powder diffraction and Fourier transform infrared spectra. Further, the CoS2/Ni and CoS2/FTO thin films are used as counter electrodes to fabricate quantum dot-sensitized solar cells. Photocurrent-voltage curves, electrochemical impedance spectroscopies and Tafel curves are measured to evaluate their photoelectrochemical properties. The short-circuit photocurrent value of quantum dot-sensitized solar cell based on the CoS2/Ni counter electrode is significantly improved compared with that of the cell based on the CoS2/FTO, and thus the light-to-electric conversion efficiency is increased from 1.95% to 3.24%. The enhancement mechanism of electrocatalytic activity and photovoltaic performance of counter electrode prepared on Ni sheet is analyzed to be less resistance of Ni sheet and higher charge transfer rate between counter electrode and electrolyte.
关键词： Quantum dot-sensitized solar cell,CoS2,Counter electrode,Electrophoretic deposition,Ni sheet
更新于2025-11-14 17:03:37