Journal of Solid State Electrochemistry最新文献

Supercapacitor technology has been continuously advancing to improve material performance and energy density by utilizing new technologies like hybrid materials and electrodes with nanostructures. Along with fundamental principles, this article covers various types of supercapacitors, such as hybrid, electric double-layer, and pseudocapacitors. Further, comprehensive electrochemical characterization methods, including galvanostatic charge–discharge, electrochemical impedance spectroscopy, cyclic voltammetry, and other techniques (structural characterization, which includes methods such as scanning electron microscopy (SEM) and transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and Brunauer–Emmett–Teller (BET) analysis), provide information on the behavior and performance of supercapacitors. Additionally, supercapacitors are being studied for their key applications, which include industrial uses, renewable energy systems, electric vehicles, and portable electronics. Along with discussing existing limitations—such as comparatively lower energy density in comparison to batteries—the article also highlights emerging trends that could help address these limitations in the future, like the development of innovative materials and inventive electrode designs. Finally, the discussion concludes with suggestions for future research focused on enhancing supercapacitor performance and broadening their range of applications, which highlights their contribution to the development of an ecosystem for energy storage that is more effective and sustainable.

In this study, we report the development of a cost-effective and highly efficient bi-functional g-C₃N₄/ZnS/SnO₂ ternary nanocomposite for electrochemical hydrogen evolution reaction (HER) and photocatalytic applications under sunlight irradiation. The nanocomposites were synthesized using a facile hydrothermal method, combining semiconducting ZnS and SnO₂ nanomaterials with g-C₃N₄ nanosheets. Comprehensive characterization techniques were employed to analyze the structural, morphological, electrochemical, and photocatalytic properties of the synthesized nanocomposite. X-ray diffraction (XRD) analysis demonstrates that the g-C₃N₄, g-C₃N₄/ZnS, and g-C₃N₄/ZnS/SnO₂ nanostructures exhibit excellent crystallinity, as evidenced by the sharp and well-defined peaks in the XRD patterns. Field emission scanning electron microscopy (FESEM) reveals the deposition of spherical ZnS nanoparticles and agglomerated SnO₂ nanoparticles on g-C₃N₄ nanosheets, forming a ternary nanocomposite structure. The g-C₃N₄/ZnS/SnO₂ ternary nanocomposite exhibits a high Brunauer–Emmett–Teller (BET) surface area of 118.123 m² g⁻¹ and an optical band gap of 2.88 eV. Electrochemical measurements show that the nanocomposite has enhanced catalytic activity for the HER, with a low Tafel slope of 92 mV dec⁻¹ and an overpotential of − 0.372 V vs. RHE at 10 mA cm⁻². Furthermore, the g-C₃N₄/ZnS/SnO₂ ternary nanocomposite demonstrates excellent photocatalytic performance, exhibiting high degradation efficiency against methylene blue (MB) dye under sunlight exposure. The synergistic effects of the ternary nanocomposite structure, high surface area, and suitable optical properties contribute to the enhanced photocatalytic and electrocatalytic activities. The developed g-C₃N₄/ZnS/SnO₂ ternary nanocomposite shows great potential as a cost-effective and highly efficient bi-functional material for sustainable energy applications of hydrogen evaluation and environmental remediation.

Untethered devices controlled by an external magnetic field are becoming more and more widely used in a wealth of applicative fields: medicine, precise micromanipulation, and environment management. Their production strongly relies on the use of complex and time-consuming technologies typically borrowed from the microelectronic field. In an attempt to reduce costs and enhance manufacturing flexibility, additive manufacturing has been investigated as a relevant alternative for untethered microrobots production. Between the large number of additive manufacturing technologies, inkjet printing is relatively poorly investigated for the production of this kind of devices, and the present work aims at exploring its potential. The work establishes a comparison between different approaches for the inkjet manufacturing of magnetically guidable microdevices. In particular, it focuses on the manufacturing of fully inkjet-printed magnetic devices by proposing two methods of production. The first consists in the electroless metallization of non-magnetic devices printed with SU-8 resin, while the second is based on the inkjet printing of a dispersion of magnetic nanoparticles in SU-8 resin. As a result, inkjet-printed devices controllable by an external magnetic field can be obtained. Multi-step and one-step production methods are compared in terms of quality of the obtained elements, easiness of production, and mechanical properties. The morphology of the finished devices, their surface quality, and their magnetic actuability are analyzed and discussed.

High-Entropy Oxides (HEOs) are emerging as promising anode materials for lithium-ion batteries (LIBs) due to their stable crystal structure and high theoretical capacity. However, the limited understanding of their intrinsic crystal structure and lithium storage mechanism has hindered their further development and application. In this study, (Y_0.2La_0.2Ce_0.2Nd_0.2Ca_0.2)₂Sn₂O₇ (M₂Sn₂O₇) nanoparticles are successfully synthesized using a hydrothermal method and then applied as an advanced anode material for LIBs. The oxygen vacancies induced by high-entropy chemistry result in the M₂Sn₂O₇ HEO exhibiting excellent cycle stability, achieving high reversible capacities of 574.2 and 430.4 mA h g⁻¹ after 100 cycles at 0.1 A g⁻¹ for half and full-cell lithium-ion batteries, respectively. This research highlights the potential of HEOs with stable structures and excellent performance as promising candidates for LIB anode materials.

Owing to the supply bottlenecks and high-cost cobalt, high-nickel, cobalt-free layered cathodes is regarded as the most affordable and representative option for lithium-ion batteries (LIBs). However, the commercialization of low-cost LiNi_0.9Mn_0.1O₂ cathodes has been hindered by their poor chemo-mechanical stability and limited cycling performance. In this study, Mg/W co-doping was employed to improve lithium batteries cycling stability by changing the lattice size. The capacity retention of the Mg/W co-doping LiNi_0.9Mn_0.1O₂ samples (Mg&W-LNMO) was 96.51% at a discharge rate of 0.5 C and a voltage interval of 2.8–4.3 V after 100 cycles electrochemical cycle tests, which was 16.7% higher than that of the LiNi_0.9Mn_0.1O₂ samples (LNMO) cathode, while maintaining intact particle morphology. The combined effect of Mg and W effectively prevented Ni/Li mixing and segregation, suppressed the leaching of transition metal ions, inhibited the phase transformation from a layered structure to a spinel configuration, and improved the structural stability of the material. These results offered an uncomplicated, productive, and scalable approach for designing cobalt-free, nickel-rich cathodes in the development of cost-effective lithium-ion batteries.

Vanillin (VAn), 4-hydroxy-3-methoxybenzaldehyde, is a natural organic compound classified as a phenolic aldehyde. It is the primary component responsible for the distinctive vanilla flavor and aroma found in vanilla beans. Beyond its culinary applications, VAn is utilized in the fragrance and cosmetic industries due to its pleasant scent. In this study, VAn was employed as a precursor for the in situ functionalization of redox-active catechol on multi-walled carbon nanotubes (MWCNTs)–modified electrode surface, designated as GCE/MWCNT@VAn-Redox, where VAn-Redox represents the redox-active product of VAn. This modified electrode functions as a surface-confined redox-active molecular species capable of efficiently electrocatalytically reducing hazardous Cr(VI) species in aqueous solutions. The chemically modified electrode (CME) exhibited a well-defined redox peak at a standard electrode potential, E° = 0.6 V vs Ag/AgCl, with a surface-excess value (Γ) of 14.2 × 10⁻⁹ mol·cm⁻² in a pH 2 HCl + KCl environment. Characterization of the modified electrode was performed using various techniques, including FE-SEM, UV–Vis, Raman, FT-IR, HRMS (organic extract), and control electrochemical experiments. Amperometric i-t and batch injection analyses (BIA) were employed to evaluate the electrocatalytic reduction, transforming the screen-printed CME into a sensitive electrochemical sensor for toxic Cr(VI) species. Notably, this innovative electrode demonstrates no interference with dissolved oxygen or various biochemicals, such as mercury, calcium, zinc, sulfate, chloride, iodide, H₂O₂, cysteine, glucose, and urea.

Afresh synthesis of PPy/TiO₂/SiO₂ (PTS) nanocomposites via in situ chemical oxidation polymerization of pyrrole and by altering the weight ratio of TiO₂/SiO₂ nanosphere (TS Ns) is executed in this work. After a significant structural and morphological analysis, the nanocomposites were investigated for electrochemical behavior in 1 M H₂SO₄ adopting CV, GCD, and EIS measurements using three as well as two-electrode system setups. Results disclose that different feeding ratios of TS Ns, corresponding variation in PPy as well in synthesized nanocomposites play an important role in the enhancement of electrochemical properties. After a comparative study, it is observed that the PTS2 that is PPy:TS (w/w) as 50:50 sample at 10 mV/s scanning rate shows the highest specific capacitance, 499 F/g, and the value accords well with that of obtained through GCD findings (413 F/g) and the areal capacitance of the optimized electrode as 838.3 mF/cm². PTS2 provided the energy density as 28.2 Wh/kg which is approximately 19 times more than that of neat PPy. The power density for PPy and PTS2 at 0.5 A/g current density was found to be 64.8 W/kg and 219 W/kg, respectively. Herein, the supercapacitor application gets strengthened with ideal capacitive behavior due to the high value (0.85) of “n” obtained through EIS findings and interpretation. It retained 92.23% of its initial current response even after covering ten thousand (10,000) charge–discharge rounds. Further, a device was assembled to show practical use of the best one configured electrode and charged for 5 min that could promptly illuminate the blue light emitting diode (LED) for 10 min.

Graphical abstract

Schematical synthesis of PPy/TiO₂/SiO₂ NCs, electrode modification, and their electrochemical study for energy storage application

The sol–gel film method was employed to produce pure and Ti-doped V₂O₅ in varying concentrations (1, 2, 3, and 4 mol%). The resulting materials were characterized using X-ray diffraction (XRD), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM–EDX), transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET) surface area analysis, and X-ray photoelectron spectroscopy (XPS) to assess their crystal structure, morphology, surface characteristics, and elemental composition. XRD results indicated that all samples, whether pure or doped, crystallized in the orthorhombic phase with a preferred orientation along the (101) plane. The introduction of doping reduced the crystallite size, which fell below 10 nm. SEM analysis revealed that the V₂O₅ appeared as nanosheets. The impact of doping on electrochemical performance was evaluated using galvanostatic charge/discharge (GCD), electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV) in a 1 M LiNO₃ electrolyte. The electrochemical tests demonstrated surface redox pseudocapacitive behavior with reversible charge/discharge capabilities, and specific capacitance values ranged from 254.6 to 352.3 F/g, depending on the sample composition, as determined by CV. The presence of dopants enhanced the electrochemical performance due to the multiple oxidation states of V and Ti, as well as the presence of oxygen vacancies (V_O^··). Specifically, the 4% Ti-doped V₂O₅ exhibited a specific capacitance (C_sp) of 352.3 F/g, energy density (E_d) of 43.3 Wh/kg, power density (P_d) of 554.2 W/kg, and maintained 69.1% cycling stability over 10,000 cycles at 1 A/g.

Recently, microRNA-223 (miR-223) has emerged as a new prognostic and diagnostic biomarker for detecting non-small cell lung cancer (NSCLC); thus, sensitive and selective detection of miR-223 is important in the early phase of cancer management. Herein, a simple miR-223 biosensor is developed using a biotin-tagged double-stranded DNA-RNA hybrid structure sandwiched between a recognition probe and a bioconjugate as a signaling unit. The recognition probe (MWCNT/AuNPs/DNA-1//GCE) is fabricated by immobilizing thiol-modified capturer DNA (DNA-1) onto a predesigned multiwall carbon nanotubes/gold nanoparticle–modified glassy carbon electrode (MWCNT/AuNPs//GCE) via Au–S interaction. However, 6-(Ferrocenyl)hexanethiol (Fc-SH) coupled streptavidin/AuNPs bioconjugate (Sv/AuNPs/Fc-SH) can selectively bind to biotinylated dsDNA-RNA hybrid via biotin − streptavidin conjugation and generates electrooxidation signal directly under applied potential. The proposed sensor demonstrates linear dynamic response as a function of log concentration of miR-223 (log C_miR-223) ranging from 1 pM to 10 nM with a relatively low detection limit of 0.73 pM (3σ/sensitivity, n = 3) and is capable of discriminating miR-223 from its homologous sequences, hence can be considered for the diagnosis of clinical samples.

Graphical Abstract

Conductive filament-based polylactic acid doped carbon black (PLA-CB) was used as an alternative to metal-based electrodes. Rhodamine B (RhB) was electrochemically polymerized on PLA-CB. The electrosynthesis of poly(rhodamine B) (PRhB) was achieved by cyclic voltammetry, galvanostatic, and potentiostatic techniques. PRhB coatings were characterized to investigate their morphology, chemical, and optical properties using different microscopic and spectroscopic techniques such as scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and UV-visible spectrophotometry (UV-vis). The theoretical UV-vis spectrum calculated with the Time-Dependent Density Functional Theory (TD-DFT) method was comparable with experimental UV-vis spectra. The modified electrode was tested for the detection of melatonin, gallic acid, dopamine, and nitrite showing an enhanced performance. The obtained results are promising for developing adherent PRhB coatings and can be used as a sensor in future studies. 3D printed conductive electrodes can be inexpensively manufactured in electrochemical laboratories using PLA-CB and reach properties well comparable to those obtained at conventional carbon or metallic electrodes, hence used for RhB polymerization.

Graphical abstract