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Cost-efficient material with an ingenious design is important in the engineering applications of flexible energy storage and electromagnetic (EM) protection. In this study, bimetallic ZnCo2S4 (ZCS) polyhedral nanoparticles homogenously embedded in the surface of porous N-doped carbon nanofiber membranes (ZCS@PCNFM) have been fabricated by electrospinning technique combined with carbonization and hydrothermal processes. As a self-assembled electrode for lithium-ion batteries (LIBs), the bimetallic ZCS nanoparticles possess rich redox reactions, good electrical conductivity, and pseudocapacitive properties, while the three-dimensional (3D) multiaperture architecture of the nanofiber film not only shortens the transfer spacing of lithium ions and electrons but also effectively tolerates the volume variation during lithiation and delithiation cycles. Benefiting from the above merits, the ZCS@PCNFM electrode exhibits good cycle performance (662.3 mA h/g at 100 mA/g after 100 cycles), superior rate capacity (401.3 mA h/g at 1 A/g) and an extremely high initial specific capacity of 1152.2 mAh/g at 100 mA/g. Meanwhile, depending on the hierarchical nanostructure and multi-component heterogeneous interface effects constructed by 3D inlaid architecture, the ZCS@PCNFM nanocomposite exhibits fascinating microwave absorption (MA) characteristics with a superhigh reflection loss (RL) of -49.7 dB at a filling content of only 20 wt% and corresponding effective absorption bandwidth (EAB, RL<-10 dB) of 5.2 GHz ranging from 12.8 to 18.0 GHz at 2.2 mm.

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Bisphenols threaten human health and sensitive detection is crucial. The present study aims to develop ternary composites of copper metal-organic framework (Cu-MOF) with AuAg microstructures. The composite structure was formed by a galvanic displacement reaction and confirmed using SEM. A binder-free catalyst was used to study the electrochemical redox reaction of bisphenol A (BPA) and bisphenol S (BPS); an irreversible cyclic voltammetric signal at +0.70 V and + 0.91 V (vs. Ag/AgCl), in the dynamic range of 20 nM to 2.0 mM, and 10 nM to 1.0 mM, with limits of detection of 2.9 nM, and 3.2 nM (S/N = 3) was obtained. Practical analysis was applied to frozen tomatoes, tuna fish, milk powder, PET bottles, raw milk, and urine samples with a recovery rate of 94.00-100.80% (n = 3). Voltammetric results were validated using HPLC detection with high precision. The sensor is a promising alternative platform for measuring BPA in food samples.

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Silicon is considered as the most felicitous anode material candidate for lithium-ion batteries on account of abundant availability, suitable operating potential, and high specific capacity. Nevertheless, drastic volume expansion during the cycle impedes its practical utilization. Herein, Si and MnO2 (Si-MO) constructed the binder-free intertwined electrode that is reported to effectively improve upon the cycling stability of Si-based materials. The Si-based electrode without a binder has good electrical conductivity, strong adhesion to the substrate, and ample space for mitigating volume expansion. The incorporation of MnO2 establishes a multiphase interface, which mitigates the electrode volume expansion, and supports the electrode structure. Furthermore, MnO2 (∼1230 mAh g-1 theoretical capacity) synergistically enhances the overall capacity of the composite electrodes. Consequently, the Si-MO composite electrode exhibits a reversible specific capacity of 1300 mAh g-1 at 420 mA g-1 and remarkable cycling performance with a specific capacity of 830 mAh g-1 after 500 cycles. In particular, a reversible specific capacity of 837 mAh g-1 at 4200 mA g-1 is achieved and remains stable during 200 cycles. This work provides a potentially feasible way to achieve the Si-based anode commercialization for LIBs.

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The porous architectures of oxygen cathodes are highly desired for high-capacity lithium-oxygen batteries (LOBs) to support cathodic catalysts and provide accommodation for discharge products. However, controllable porosity is still a challenge for laminated cathodes with cathode materials and binders, since polymer binders usually shield the active sites of catalysts and block the pores of cathodes. In addition, polymer binders such as poly(vinylidene fluoride) (PVDF) are not stable under the nucleophilic attack of intermediate product superoxide radicals in the oxygen electrochemical environment. The parasitic reactions and blocking effect of binders deteriorate and then quickly shut down the operation of LOBs. Herein, the present work proposes a binder-free three-dimensional (3D) porous graphene (PG) cathode for LOBs, which is prepared by the self-assembly and the chemical reduction of GO with triblock copolymer soft templates (Pluronic F127). The interconnected mesoporous architecture of resultant 3D PG cathodes achieved an ultrahigh capacity of 10,300 mAh g-1 for LOBs. Further, the cathodic catalysts ruthenium (Ru) and manganese dioxide (MnO2) were, respectively, loaded onto the inner surface of PG cathodes to lower the polarization and enhance the cycling performance of LOBs. This work provides an effective way to fabricate free-standing 3D porous oxygen cathodes for high-performance LOBs.

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Integrated monolithic electrodes (IMEs) free of inactive components demonstrate great potential in boosting energy-power densities and cycling life of lithium-ion batteries. However, their practical applications are significantly limited by low active substance loading (< 4.0 mg cm-2 and 1.0 g cm-3), complicated manufacturing process, and high fabrication cost. Herein, employing industrial Cu-Mn alloy foil as a precursor, a simple neutral salt solution-mediated electrochemical dealloying strategy is proposed to address such problems. The resultant Cu-Mn IMEs achieve not only a significantly larger active material loading due to the in situ generated Cu2O and MnOx (ca. 16.0 mg cm-2 and 1.78 g cm-3), simultaneously fast transport of ions and electrons due to the well-formed nanoporous structure and built-in Cu current collector, but also high structural stability due to the interconnected ligaments and suitable free space to relieve the volume expansion upon lithiation. As a result, they demonstrate remarkable performances including large specific capacities (> 5.7 mAh cm-2), remarkable pseudocapacitive effect despite the battery-type constitutes, long cycling life, and good working condition in a lithium-ion full cell. This study sheds new light on the further development of IMEs, enriches the existing dealloying techniques, and builds a bridge between the two.

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A ternary hierarchical hybrid Ni@CoxSy/poly(3,4-ethylenedioxythiophene)-reduced graphene oxide (Ni@CoxSy/PEDOT-rGO) is rationally designed and in situ facilely synthesized as electrocatalyst to construct a binder-free sensing platform for non-enzymatic glucose monitoring through traditional electrodeposition procedure. The as-prepared Ni@CoxSy/PEDOT-rGO presents unique hierarchical structure and multiple valence states as well as strong and robust adhesion between Ni@CoxSy/PEDOT-rGO and GCE. Profiting from the aforementioned merits, the sensing platform constructed under optimal conditions achieved a wide detection range (0.2 µM ~ 2.0 mM) with high sensitivity (1546.32 µA cm-2 mM-1), a rapid response time (5 s), an ultralow detection limit (0.094 µM), superior anti-interference performance, excellent reproducibility and considerable stability. Furthermore, the sensor demonstrates an acceptable accuracy and appreciable recoveries ranging from 90.0 to 102.0% with less than 3.98% RSD in human blood serum samples, indicating the prospect of the sensor for the real samples analysis. It will provide a strategy to rationally design and fabricate ternary hierarchical hybrid as nanozyme for glucose assay.

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In the realm of electronics and electric energy storage, the convergence of organic and metallic materials has yielded promising outcomes. In this study, we introduce a novel metal-organic polymer synthesized from Cyamelurate and copper (KCu-Cy) and explore its application as an electrode for a supercapacitor. This material was pressed onto a stainless-steel grid as a thin film and synthesized on nickel foam. Comprehensive characterization was carried out to confirm the synthesis, ensure phase purity, and investigate atomic interactions. Single Crystal X-ray Diffraction (SCXRD) and Powder X-ray Diffraction (PXRD) analyses verified the synthesis and phase purity, shedding light on atomic arrangements. Fourier Transform Infrared Spectroscopy (FTIR) analyses provided insights into characteristic peaks within the material. Thermal Gravimetric Analysis (TGA) gauged stability and durability. Electrochemical performance was assessed through cyclic voltammetry. Notably, the nickel-supported electrodes, devoid of binders, exhibited exceptional specific capacity, reaching 1210.89 F/g at a scan rate of 5 mV/s, in contrast to 363.73 F/g for the pressed thin film on the stainless-steel grid, which incorporated a conductive agent and binder. Cu-Cy displayed impressive cyclization resistance, with a capacity retention of 90 % even after 11000 cycles. These findings underline the promise of Cu-Cy as a high-performance electrode material for supercapacitors, particularly in binder-free configurations, and suggest its potential in advanced energy storage applications.

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Carbon-based electrode materials have widely been used in supercapacitors. Unfortunately, the fabrication of the supercapacitors includes a polymeric binding material that leads to an undesirable addition of weight along with an increased charge transfer resistance. Herein, binder-free and lightweight electrodes were fabricated using powder processing of carbon nanofibers (CNFs) and graphene nanoplatelets (GNPs) resulting in a hybrid all-carbon composite material. The structural, morphological, and electrochemical properties of the composite electrodes were studied at different concentrations of GNPs. The specific capacitance (Cs) of the CNFs/GNPs composite was improved by increasing the concentration of GNPs. A maximum Cs of around 120 F g-1was achieved at 90 wt% GNPs which is around 5-fold higher in value than the pristine CNFs in 1 M potassium hydroxides (KOH), which then further increased to 189 F g-1in 6 M KOH electrolyte. The energy density of around 20 Wh kg-1with the corresponding power density of 340 W kg-1was achieved in the supercapacitor containing 90 wt% GNPs. The enhanced electrochemical performance of the composite is related to the presence of a synergistic effect and the CNFs establishing conductive/percolating networks. Such binder-free all-carbon electrodes can be a potential candidate for next-generation energy applications.

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Binary metal phosphate electrodes have been widely studied for energy storage applications due to the synergistic effects of two different transition elements that able to provide better conductivity and stability. Herein, the battery-type binder-free nickel-manganese phosphate (NiMn-phosphate) electrodes were fabricated with different Ni:Mn precursor ratios via microwave-assisted hydrothermal technique for 5 min at 90 °C. Overall, NiMn3P electrode (Ni:Mn = 1:3) showed an outstanding electrochemical performance, displaying the highest specific (areal) capacity at 3 A/g of 1262.4 C/g (0.44 C/cm2), and the smallest charge transfer resistance of 108.8 Ω. The enhanced performance of NiMn3P electrode can be ascribed to the fully grown amorphous nature and small-sized flake and flower structures of NiMn3P electrode material on the nickel foam (NF) surface. This configuration offered a higher number of active sites and a larger exposed area, facilitating efficient electrochemical reactions with the electrolyte. Consequently, the NiMn3P//AC electrode combination was chosen to further investigate its performance in supercapattery. The NiMn3P//AC supercapattery exhibited remarkable energy density of 105.4 Wh/kg and excellent cyclic stability with 84.7% retention after 3000 cycles. These findings underscored the superior electrochemical performance of the battery-type binder-free NiMn3P electrode, and highlight its potential for enhancing the overall performance of supercapattery.

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Ternary manganese-based oxides, such as CaMn2O4 (CMO) nanofibers fabricated via the electrospinning technique, have the potential to offer higher reversible capacity through conversion reactions in comparison to that of carbon-based anodes. However, its poor electrical conductivity hinders its usage in lithium-ion batteries (LIBs). Hence, to mitigate this issue, controlled single-step in situ decoration of highly conducting metallic-phase MoS2@CMO nanofibers has been achieved for the first time via the electrophoretic deposition (EPD) technique and utilized as a binder-free nanocomposite anode for LIBs. Further, the composition of MoS2@CMO nanofibers has also been optimized to attain better electronic and ionic conductivity. The morphological investigation revealed that the flakes of MoS2 nanoflowers are successfully and uniformly decorated over the CMO nanofibers' surface, forming a cactus-type morphology. As a binder-free nanocomposite LIB anode, CMOMS-7 (7 wt % MoS2@CMO) demonstrates a specific capacity of 674 mA h g-1 after 60 cycles at 50 mA g-1 and maintains a capacity of 454 mA h g-1 even after 300 cycles at 1000 mA g-1. Further, the good rate performance (102 mA h g-1 at 5000 mA g-1) of CMOMS-7 can be ascribed to the enhanced electrical conductivity provided by the metallic-phase MoS2. Moreover, the feasibility of CMOMS-7 is thoroughly investigated by using a full Li-ion cell incorporating a binder-free cathode of LiNi0.3Mn0.3Co0.3O2 (NMC). This configuration showcases an impressive energy density of 154 Wh kg-1. Thus, the hierarchical and aligned structure of CMO nanofibers combined with highly conductive MoS2 nanoflowers facilitates charge transportation within the composite electrodes. This synergistic effect significantly enhances the energy density of the conversion-based nanocomposites, making them highly promising anodes for advanced LIBs.

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The present work addresses the limitations by fabricating a wide range of negative electrodes, including metal nitrides/sulfides on a 3D bimetallic conductive porous network (3D-Ni and 3D-NiCo) via a dynamic hydrogen bubble template (DHBT) method followed by vapour phase growth (VPG) process. Among the prepared negative electrodes, the 3D-Fe3S4-Fe4N/NiCo nanostructure demonstrates an impressive specific capacitance (Cs) of 1125 F g-1 (2475 mF cm-2) at 1 A g-1 with 80% capacitance retention over 5000 cycles. Similarly, a 3D-Mn3P nanostructured positive electrode fabricated via electrodeposition followed by a phosphorization process exhibits a maximum specific capacity (Cg) of 923.04 C g-1 (1846.08 mF cm-2) at 1 A g-1 with 80% stability. A 3D-Mn3P/Ni//3D-Fe3S4-Fe4N/NiCo supercapattery is also assembled, and it shows a notable CS of 151 F g-1 at 1 A g-1, as well as a high energy density (ED) of 51 Wh kg-1,a power density (PD) of 782.57 W kg-1 and a capacitance efficiency of 76% over 10 000 cycles. This may be ascribed to the use of a bimetallic 3D porous conductive template and the attachment of transition metal sulfide and nitride. The development of negative electrodes and supercapattery devices is greatly aided by this exploration of novel synthesis techniques and material choice.

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Li-O2 batteries (LOB) performance degradation ultimately occurs through the accumulation of discharge products and irreversible clogging of the porous electrode during the cycling. Electrode binder degradation in the presence of reduced oxygen species can result in additional coating of the conductive surface, exacerbating capacity fading. Herein, a facile method to fabricate free-standing is established, binder-free electrodes for LOBs in which multi-wall carbon nanotubes form cross-linked networks exhibiting high porosity, conductivity, and flexibility. These electrodes demonstrate high reproducibility upon cycling in LOBs. After cell death, efficient and inexpensive methods to wash away the accumulated discharge products are demonstrated, as reconditioning method. The second life usage of these electrodes is validated, without noticeable loss of performance. These findings aim to assist in the development of greener high energy density batteries while reducing manufacturing and recycling costs.

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In this study, a three-step strategy including electrochemical cathode deposition, self-oxidation, and hydrothermal reaction is applied to prepare the LiMn2 O4 nanosheets on carbon cloth (LMOns@CC) as a binder-free cathode in a hybrid capacitive deionization (CDI) cell for selectively extracting lithium from salt-lake brine. The binder-free LMOns@CC electrodes are constructed from dozens of 2D LiMn2 O4 nanosheets on carbon cloth substrates, resulting in a uniform 2D array of highly ordered nanosheets with hierarchical nanostructure. The charge/discharge process of the LMOns@CC electrode demonstrates that visible redox peaks and high pseudocapacitive contribution rates endow the LMOns@CC cathode with a maximum Li+ ion electrosorption capacity of 4.71 mmol g-1 at 1.2 V. Moreover, the LMOns@CC electrode performs outstanding cycling stability with a high-capacity retention rate of 97.4% and a manganese mass dissolution rate of 0.35% over ten absorption-desorption cycles. The density functional theory (DFT) theoretical calculations verify that the Li+ selectivity of the LMOns@CC electrode is attributed to the greater adsorption energy of Li+ ions than other ions. Finally, the selective extraction performance of Li+ ions in natural Tibet salt lake brine reveals that the LMOns@CC has selectivity ( α Mg 2 + Li + $\alpha _{{\mathrm{Mg}}^{2 + }}^{{\mathrm{Li}}^ + }$ = 7.48) and excellent cycling stability (100 cycles), which would make it a candidate electrode for lithium extraction from salt lakes.

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Switching from a linear mode of waste management to a circular loop by transforming plastic waste into carbon nanotubes (CNTs) is a promising approach to current plastic waste treatment. One of the many applications of CNTs is its use for electrocatalytic water splitting for hydrogen evolution. Existing methods of CNTs-based hydrogen evolution reaction (HER) electrode fabrication involve additives like polymeric binders and additional steps to improve CNT dispersion, which are detrimental to the CNT structure and properties. The in-situ fabrication approach can potentially be a one-pot solution to HER electrode synthesis. In this study, polyolefins pyrolysis gas and a Co:Ni:Mg catalyst were used to fabricate binder-free CNTs-based electrodes on different substrates for HER. The study assessed CNT quality on conductive carbon paper, semiconductive silicon, and dielectric glass substrates, evaluating their HER performance in 1 M KOH. A mixture of hollow-core, bamboo-like, and cup-stacked arrangement nanotubes were synthesized on the substrates, with CNTs on glass and carbon paper substrates possessing better graphitization than CNTs grown on silicon. This is in agreement with HER performance, whereby the as-prepared electrodes required overpotentials of 267 mV, 241 mV, and 216 mV for silicon, glass, and carbon paper, respectively, to achieve 10 mA/cm2. Despite being poorly conductive, the glass substrate electrode achieved a lower overpotential than the silicon electrode. Additionally, the as-prepared silicon electrode faced a delamination issue likely attributed to the lower surface energy of the silicon substrate surface, demonstrating the weaker adhesion between the CNTs and silicon surface. The proposed approach thus showed that the in-situ fabricated electrodes performed better than separately synthesized CNTs prepared into electrodes by 27.4% and 14.2% for carbon paper and glass substrates, respectively. The improved performance of the as-prepared, binder-free electrodes can be linked to the lower charge-transfer resistance and reduced contact resistance between the CNTs and substrate.

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The entire world is aware of the serious issue of global warming and therefore utilizing renewable energy sources is the most encouraging steps toward solving energy crises, and as a result, energy storage solutions are necessary. The supercapacitors (SCs) have a high-power density and a long cycle life, they are promising as an electrochemical conversion and storage device. In order to achieve high electrochemical performance, electrode fabrication must be implemented properly. Electrochemically inactive and insulating binders are utilized in the conventional slurry coating method of making electrodes to provide adhesion between the electrode material and the substrate. This results in an undesirable "dead mass," which lowers the overall device performance. In this review, we focused on binder-free SCs electrodes based on transition metal oxides and composites. With the best examples providing the critical aspects, the benefits of binder-free electrodes over slurry-coated electrodes are addressed. Additionally, different metal-oxides used in the fabrication of binder-free electrodes are assessed, taking into account the various synthesis methods, giving an overall picture of the work done for binder-free electrodes. The future outlook is provided along with the benefits and drawbacks of binder-free electrodes based on transition metal oxides.

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The current collector serves as a crucial element in supercapacitors, acting as a medium between the electrode material and the substrate. Due to its excellent conductivity, a metal collector is typically favored. Enhancing the binding strength between the collector and the substrate as well as between the collector and the electrode material has emerged as a critical factor for enhancing the capacitance performance. In this study, a Ag film with a grass root-like structure was initially grown on a PI substrate through the surface modification and ion exchange (SMIE) process. This Ag interlocking structure contributes to strong binding between the PI substrate and Ag without compromising the mechanical properties of the Ag film. To further enhance the electrochemical properties at low scan rates, electroless-plated Cu was subsequently deposited on the Ag film to form the Cu/Ag current collector. Moreover, the Cu within the Cu/Ag current collector served as a precursor for the growth of FeOOH-Cu(OH)2 via a two-step in situ method. The resulting FeOOH-Cu(OH)2/Cu/Ag structure as a whole is binder-free. Supercapacitors employing symmetric FeOOH-Cu(OH)2/Cu/Ag structures were assembled, and their energy storage properties were investigated. The solution-based low-temperature process used in this study offers the potential for cost-effective and large-scale applications.

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Bimetallic selenide compounds show great potential as supercapacitor electrode materials in energy storage and conversion applications. In this work, a coral-like MnCo selenide was grown on nickel foam using a facile electrodeposition method to prepare binder-free supercapacitor electrodes. The heating temperature was varied to tune the morphology and crystal phase of these electrodes. Excellent electrochemical performance was achieved due to the unique coral-like, dendritic- dispersed structure and a bimetallic synergistic effect, including high specific capacitance (509 C g-1 at 1 A g-1) and outstanding cycling stability (94.3% capacity retention after 5000 cycles). Furthermore, an asymmetric supercapacitor assembled with MnCo selenide as the anode and active carbon as the cathode achieved a high specific energy of 46.2 Wh kg-1 at 800 W kg-1. The work demonstrates that the prepared coral-like MnCo selenide is a highly promising energy storage material.

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Binder-free electrodes offer a great opportunity for developing high-performance sodium-ion batteries (SIBs) aiming at the application in energy storage devices. Tin selenide (SnSe) is considered to be a promising anode material for SIBs owing to its high theoretical capacity (780 mA h g-1). In this work, a SnSe nanosheet array (SnSe NS) on a carbon cloth is prepared using a vacuum thermal evaporation method. The as-prepared SnSe NS electrode does not have metal current collectors, binders, or any conductive additives. In comparison with the electrode of SnSe blocky particles (SnSe BP), the SnSe NS electrode delivers a higher initial charge capacity of 713 mA h g-1 at a current density of 0.1C and maintains a higher charge capacity of 410 mA h g-1 after 50 cycles. Furthermore, the electrochemical behaviors of the SnSe NS electrode are determined via pseudocapacitance and electrochemical impedance spectroscopy measurements, indicating a faster kinetic process of the SnSe NS electrode compared to that of the SnSe BP. Operando X-ray diffraction measurements prove that the SnSe NS exhibits better phase reversibility than the SnSe BP. After the cycles, the SnSe NS electrode still maintains its particular structure. This work provides a feasible method to prepare SnSe nanostructures with high capacity and improved sodium ion diffusion ability.

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This work reports anin situ, one-step hydrothermal preparation procedure of a binder-free electrode growth of Ni6Se5on nickel foam (Ni6Se5/NF) with a rod-like structure. Ni6Se5is an enveloped transition metal chalcogenides of formula M(n+1)Xn(where 2 ≤n≤ 8, M is a transition metal and X is chalcogen) of the nickel selenide family. The Ni6Se5/NF electrode described here demonstrates an exceptional lifetime of 81% capacitance retention over 20000 cycles and a high specific capacitance of 473.5 Fg-1at a current density of 4 Ag-1. The Ni6Se5/NF/activated carbon asymmetric supercapacitor (SC) exhibits a remarkable 97.3 Whkg-1energy density and a 2325 Wkg-1power density. Ni6Se5served as an active electrode material in SC applications and offered exceptional power density and long cycle life. Ni6Se5/NF, used as an anode for Li-ion batteries, has a lithium storage capacity of 939.7 mAhg-1at 100 mAg-1current density. Ni6Se5's (active electrode material) excellent energy storage capability, which was previously unreported, is particularly beneficial for electrochemical energy storage device applications.

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The development of lithium-ion batteries with simplified assembling steps and fast charge capability is crucial for current battery applications. In this study, we propose a simple in-situ strategy for the construction of high-dispersive cobalt oxide (CoO) nanoneedle arrays, which grow vertically on a copper foam substrate. It is demonstrated that this nanoneedle CoO electrodes provide abundant electrochemical surface area. The resulting CoO arrays directly act as binder-free anodes in lithium-ion batteries with the copper foam functioning as the current collector. The highly-dispersed feature of the nanoneedle arrays enhances the effectiveness of active materials, leading to outstanding rate capability and superior long-term cycling stability. These impressive electrochemical properties are attributed to the highly-dispersed self-standing nanoarrays, the advantages of binder-free constituent, and the high exposed surface area of the copper foam substrate compared to copper foil, which enrich active surface area and facilitate charge transfer. The proposed approach to prepare binder-free lithium-ion battery anodes streamlines the electrode fabrication steps and holds significant promise for the future development of the battery industry.