Optimal Electrode Research Articles

On the benefits of structured composite electrodes in solid oxide cells

Functional composites of electronic and ionic conductors are the backbone of oxygen and fuel electrodes in solid oxide cells. A typical oxygen electrode is fabricated from a lanthanum strontium manganite and yttria-stabilized zirconia (LSM-YSZ) composite, while the fuel electrode is based on a Ni-YSZ cermet. While the composite materials exhibit enhanced kinetic capabilities, the electron-conductive phases, i.e., LSM and Ni, exhibit high electrical conductivity. The goal of this study was to develop an electrode layout with enhanced performance by tailoring the benefits of both, the composites and the single-phase electron conductors, within individual electrodes. The electrodes were fabricated in a two-layer layout with different thicknesses by screen-printing: composite material layer, electron-conductive material. The results suggested that the presence of YSZ is essential in the entire electrode body of a fuel electrode for enhanced performance as it increases the triple phase boundary length, as well as mechanical stability by forming a scaffold for the Ni network. Hence, for the optimal performance a thick layer of Ni-YSZ composite is required. On the contrary, the optimal oxygen electrode requires only very thin layer of the composite, otherwise the presence of YSZ is retarding the electrode’s performance.Graphical abstract

Investigation of high-quality-factor aluminum nitride MEMS cantilever resonators

This paper presents the design, fabrication, and characterization of cantilever-type resonators with a novel stacked structure. Aluminum nitride is adopted as the material for both the structural layer and the piezoelectric layer; this simplifies the fabrication process and improves the quality factor of the resonator. Both in-plane and out-of-plane flexural modes were investigated. The effect of the structural dimensions and electrode patterns on the resonator’s performance were also studied. Finite-element simulations and experiments examining anchor loss and thermoelastic damping, which are the main loss mechanisms affecting the quality factor of these resonators, were carried out. The optimal structural dimensions and electrode patterns of the cantilever-type resonators are presented. A quality factor of 7922 with a motional impedance of 88.52 kΩ and a quality factor of 8851 with a motional impedance of 67.03 kΩ were achieved for the in-plane and out-of-plane flexural-mode resonators, respectively. The proposed resonator design will contribute to the development of high-performance devices such as accelerometers, gyroscopes, and pressure sensors.

Facile synthesis of N-doped NiCo-LDH nanowire with rich oxygen vacancies by nonthermal plasma for high-performance asymmetric capacitor electrode

Layered double hydroxides (LDHs) have been served as potential pseudo-capacitive materials, especially for high-performance supercapacitors. However, the characteristics like limited capacitance, poor conductivity, and stability of LDHs severely confine their extensive applications for future energy-storage devices. It is urgent to seek a new and simple method to modify LDH materials, to improve its electrochemical performance and apply it to supercapacitors. Herein, a facile in-situ non-thermal plasma (NTP) treatment is conducted to modify NiCo-LDH nanowires for better electrochemical performance, resulting from the introduction of N-doping and oxygen vacancies by N2 NTP. All these instructive synergies provide the optimum electrode (P-NiCoNW/CC-150) after the NTP treatment under the power of 150 W with outstanding capacitance performance of 4320 mF/cm2 at 2 mA/cm2, and superior cycling stability along with capacitance retention of 117.3 %. Most importantly, an asymmetric supercapacitor device is assembled, employing P-NiCoNW/CC-150 and oxidized carbon cloth as cathode and anode electrodes respectively, exhibiting a particularly high energy density of 364 μWh/cm2 when the power density is 4505 μW/cm2. This work confirms a feasible and green NTP method to synthesize high-performance electrodes for practical applications in future energy-storage devices but not limited to supercapacitors.

Optimal electrode configuration and system design of compactly-assembled industrial alkaline water electrolyzer

The production of green hydrogen by water electrolysis is an effective way to realize the utilization of renewable energy and decarbonization, efficient water electrolysis equipment is of great significance to reduce energy consumption and accelerate the deployment of hydrogen production infrastructure. This paper reports the optimal electrode configuration adapted to actual industrial conditions. The aim of this paper is to study the electrode structure effect and system design of compactly-assembled industrial electrolyzer under the actual operating conditions, so as to find out more suitable electrolyzer configuration parameters. Firstly, the principle and structural parameter design of industrial electrolyzer are carried out, and compactly-assembled industrial alkaline water electrolyzer (22 cells) was manufactured. Secondly, a balance of plant (BOP) system was built and the fully automatic operation process was designed. Finally, a system-level alkaline water electrolysis (AWE) hydrogen production system (including compactly-assembled electrolyzer and BOP) was established. The effect of different expanded meshes and woven meshes on the energy consumption of AWE equipment was tested, and the system component cost was analyzed. Industrial system-level test results show that the electrode dominant parameters affecting AWE performance are different under varying current densities. From the perspective of industrial application, it is more suitable for the strand width and pore width of the woven mesh to be about 0.2 mm, it achieved 4.3kWh/m3H2@4000 A/m2 based on the optimized configuration parameters. This study is helpful to the selection of electrode parameters and optimal configuration for industrial AWE equipment, at the same time, it provides a reference for the design of electrolyzer, BOP and system control process.

Ultrasound assisted electrochemical oxidation of synthetic dye wastewater

ABSTRACT This study reports the treatment of synthetic dye wastewater in a sono-electrochemical reactor. The influence of three different supporting electrolytes (Na2SO4, NaCl, and Na2NO3) on % decolorisation was studied and higher decolorisation was observed with NaCl. The increase in applied current density (0.25, 0.5, 0.75, 1, 1.25 A/dm2) enhanced the color removal and the optimum current density arrived was 1.25 A/dm2. The % decolorisation was studied at three different pH (3, 7 & 11), and about 95.7% decolorisation was observed at pH 3. The inter electrode distance of 1 cm gave highest decolorisation. The addition of Na2SO4 and Na2NO3 in the sonolyzer bath did not influence the % decolorisation significantly. The sono-electrochemical process gave 99.16% decolorisation and 91.15% COD reduction while the electrochemical process gave 94.79% decolorisation and 76.82% COD reduction. The optimum electrolyte concentration, current density, pH and electrode distance of 0.5 g/L, 1.25 A/dm2, 3, and 1 cm, respectively gave highest decolorisation. The reaction kinetics of the sono-electrochemical oxidation treatment was also investigated. The higher mineralisation rate at a lower residence time indicates that the combined treatment is promising for degrading recalcitrant compounds present in wastewater.

Facilitating light utilization and electron transfer of TiO2 nanotube arrays for catalyzing photoelectrochemical water reduction via acid etching and copper doping

Photoelectrochemical catalytic capability mainly relies on light absorption and charge transfer efficiency. TiO2 nanotube array (TNA) having suitable band edges and one-dimensional hollow structure is regarded as one of efficient photoelectrocatalysts toward water reduction. In this study, two strategies are firstly applied to modify TNA as the photocatalyst of water reduction. Ti foils are etched by acid to produce multiple light reflections planes for improving light absorption, and Cu is doped in TNA to enhance charge transfer efficiency. The optimal Cu-doped TNA electrode on the acid-etched Ti foil presents a much smaller overpotential of 91 mV at 10 mA/cm2 compared with that of the undoped TNA (524 mV). A smaller Tafel slope of 134 mV/dec is obtained for the optimal Cu-doped TNA electrode than that of the undoped TNA (167 mV/dec). After measuring the photoelectrochemical performance for 1000 cycles, overpotential and charge-transfer resistance of modified TNA are largely reduced owing to activation. Current retention of 96.7% is achieved after continuously illuminating for 10 h. Highly improved photoelectrochemical catalytic ability of TNA modified by acid etching and Cu doping provides new pages for material modifications on substrate and active material.

WS2 nanosheets vertically grown on Ti3C2 as superior anodes for lithium-ion batteries

Tungsten disulfide (WS2) is considered as a promising anode material for high-performance lithium-ion batteries (LIBs) result from its inherent characteristics such as high theoretical capacity, large interlayer spacing and weak interlayer Van der Waals force. Nevertheless, WS2 has the drawbacks of easy agglomeration, severe volume expansion and high Li+ migration barrier, which lead to rapid capacity degradation and imperfect rate ability. In this work, a novel two-dimensional (2D) hierarchical composite (Ti3C2/WS2) consisting of WS2 nanosheets vertically grown on titanium carbide (Ti3C2) nanosheets is prepared. Thanks to this distinctive hierarchical structure and synergy between WS2 and Ti3C2, the Ti3C2/WS2 composite demonstrates exceptional electrochemical performance in LIBs. In addition, we investigate the effect of the mass proportion of WS2 in Ti3C2/WS2 composite on the electrochemical performance, and find that the optimal mass ratio of WS2 is 60%. As expected, the optimal electrode exhibits a high specific capacity (650 mAh/g at 0.1 A/g after 100 cycles) and ultra-long cycle stability (400 mAh/g at 1.0 A/g after 5000 cycles).

Fe nanoclusters anchored in biomass waste-derived porous carbon nanosheets for high-performance supercapacitor

Metal-nanocluster materials have gradually become a promising electrode candidate for supercapacitor application. The high-efficient and rational architecture of these metal-nanocluster electrode materials with satisfied supercapacitive performance are full of challenges. Herein, Fe-nanocluster anchored porous carbon (FAPC) nanosheets were constructed through a facile and low-cost impregnation-activation strategy. Various characterization methods documented that FAPC nanosheets possessed a mesopore-dominated structure with large surface area and abundant Fe-N4 active sites, which are crucial for supercapacitive energy storage. The optimal FAPC electrode exhibited a high specific capacitance of 378 F/g at a specific current of 1 A/g and an excellent rate capability (271 F/g at 10 A/g), which are comparable or even superior to that of most reported carbon candidates. Furthermore, the FAPC-based device achieved a desired specific energy of 14.8 Wh/kg at a specific power of 700 W/kg. This work opens a new avenue to design metal-nanocluster materials for high-performance biomass waste-based supercapacitors.

A study on defect, doping, and performance of ETLs (ZnO, TiO2, and IGZO) for the lead-free CsSnCl3 perovskite solar cell by SCAPS-1D framework

The potential of lead-free perovskite materials using cesium as an organic cation has been explored as a replacement for lead-based perovskite absorbers to minimize toxicity. These materials exhibit high stability, a tunable bandgap, and superior optoelectronic properties compared to lead-based materials. Extensive studies have investigated Sn-based cesium tin chloride (CsSnCl3) in the literature, focusing on multiple hole transporting layers (HTLs) and electron transporting layers (ETLs). A numerical study has been conducted to study the effects of thickness, series, and shunt resistance, as well as favorable band alignment with the absorber, HTL, and ETL layers. According to the literature, ETLs such as TiO2, ZnO, and IGZO, in combination with CBTS as the HTL, have emerged as the most promising candidates for achieving optimal fabrication of CsSbCl3 devices. However, several investigations have yet to be covered in the reports. These include analyzing the effects of absorber and interface defects on the ETLs/HTLs layers, determining the optimal metal back contact electrode, and optimizing the doping concentration of the absorber or ETLs/HTLs to achieve device optimization and the desired operating temperature. Through the optimization process, the study identified the optimum numerical values necessary to achieve higher device performance. It specifically found that ZnO performs the best as an ETL candidate, and the configuration combination of ITO/ZnO/(CsSnCI3)/CBTS/Se emerged as the most favorable compared to the values reported in the literature.

Cochlear Implant Insertion Routes and Intra-operative Electrophysiological Measurements: A Retrospective Analysis at a Tertiary Care Centre.

Cochlear implant surgeries are performed by different surgical routes, Round window (RW), Extended round window (Ext RW) and Cochleostomy (C). Optimum intracochlear electrode placement is important to achieve a successful outcome. Intra-operative electrophysiological testing (Impedance and ECAP) is crucial to assess the device function and appropriate electrode placement. The variability of portal of electrode insertion might affect the neural response and its characteristics. To compare the intraoperative electrophysiological measurements (Impedance and ECAP) for possible differences on auditory nerve stimulation across the three electrode insertion routes. This is a retrospective data analysis of 47 cochlear implant recipients at a tertiary care centre in Central India over a period of 4 years. They were broadly divided into two groups depending on the electrode design as full banded and half banded. Intraoperative impedances were recorded for different modes of stimulation and ECAP measured at E5, E10, E15, E20 electrodes in both the groups across the three insertion routes. In the half-banded group, the impedance values in different modes CG, MP1, MP2, MP1 + 2 did not differ significantly among the surgical routes at all four electrodes. While in the full banded group, for CG mode impedance values at E5 differ significantly. Rest for other modes in full banded group, there was no statistically significant difference across the three routes. The present study supports that there is no statistically significant difference in the intraoperative impedance and ECAP measurements in both, the full-banded and half- banded electrodes across the three surgical routes implying that, all the three surgical approaches provide equal stimulation of the auditory nerve. The CI surgeon can select the electrode insertion portal based on the surgical anatomy, the implant type and individual preferences.

Phase regulation for electrochemical rapid reconstructed ZIFs-derived hierarchical multiphase NiCoMn-Se for supercapacitors with high energy density and stability

Transition metal selenides (TMSes) have significant advantages in energy storage materials, and stimulating the material activity to enhance the performance of electrodes can realize hybrid supercapacitors (HSCs) with high practical value. Herein, the rapid reconstruction of ZIFs (zeolite-imidazole-frameworks) with the assistance of electrochemical methods is guided directionally to generate active materials and construct stable hollow layered NiCoMn-LDH@CNFs (carbon‑nitrogen frameworks). The multiphase selenides (NiCoMn-Se@CNFs) with abundant phase valence after controlled selenization enhance the redox reaction activity, and the electrodes with high energy density and stability are successfully prepared. After systematically studying the influence of time selenization and metal content, proportion, and phase regulation, the capacity of the optimal electrode NiCoMn-Se@CNFs can reach 487.5 mAh g−1 at 1 A g−1 (3510.0 F g−1). The assembling HSC (NiCoMn-Se//activated carbon) shows excellent energy density (90.8 Wh kg−1 at 0.8 kW kg−1) and ultra-high stability (103.0 %, 20,000 cycles), which proved the high efficiency/rationality of the electrode design.

Carbonized wood-based electrode anchored with Cu/Cu3P Nano particles fabricated from wood-based adsorbent for boosting capacitive performance

In this study, phosphorylated Paulownia wood is used as a starting material to construct self-supporting supercapacitor electrodes by carbonization after adsorption of Cu2+ in simulated wastewater at low concentrations. The specific capacitance of the electrodes is synergistically improved by increasing the specific surface area, doping with heteroatoms and loading with pseudocapacitive substances. The electrodes are systematically characterized through various techniques, and the results show that the adsorbed Cu2+ was converted into Cu/Cu3P NPs during the carbonization process. The electrochemical performance of different electrodes is characterized and compared. CPEW-Cu90 is identified as the optimal electrode, and its specific surface area is 731.96 cm2 g−1, nitrogen doping amount is 1.88 %, and copper loading amount is 22.85 % (the molar ratio of Cu to Cu3P was 0.40:1). In terms of electrochemical performance, CPEW-Cu90 has an Rct of 2.18 Ω and a mass specific capacitance of 481.2 F g−1 at a current density of 100 mA g−1, the assembled self-supporting symmetric supercapacitor exhibits an energy density of 18.67 W h−1kg−1 and excellent structural stability, and its capacitance remains at 93.08 % after 1000 cycles. Overall, a self-supporting, low-cost, high-performance carbonized wood-based supercapacitor is fabricated from the wood-based adsorbent.

Toward high-performance energy and power battery cells with machine learning-based optimization of electrode manufacturing

The optimization of the electrode manufacturing process is important for upscaling the application of Lithium-Ion Batteries (LIBs) to cater for growing energy demand. LIB manufacturing is important to be optimized because it determines the practical performance of the cells when the latter are being used in applications such as electric vehicles. In this study, we tackled the issue of high-performance electrodes for desired battery applications by proposing a data-driven approach supported by a deterministic machine learning-assisted pipeline for bi-objective optimization of the electrochemical performances. This pipeline allows the inverse design of the process parameters to adopt to manufacture electrodes for energy or power applications. This work is an analogy to our previous work that addressed the optimization of the electrode microstructures for kinetic, ionic, and electronic transport properties improvement. An electrochemical model is fed with the electrode properties characterizing the electrode microstructures generated by manufacturing simulations, and used to simulate the electrochemical performances. Secondly, the resulting dataset was used to train a deterministic model to implement fast optimizations to identify optimal electrodes. Our results suggested a high amount of active material, combined with intermediate values of solid content in the slurry and calendering degree, to achieve the optimal electrodes.

RGO and CNTs synergistically modified mixed-phase nickel sulfide nanohybrids with abundant redox-active sites for high-performance hybrid supercapacitors

Hybrid supercapacitors (HSCs) integrating high energy density and power density have great prospects for applications in new high-performance energy storage and conversion devices. Herein, a novel reduced graphene oxide (RGO) and carbon nanotubes (CNTs) synergistically modified mixed-phase nickel sulfide (NiS/NiS2) nanohybrids (NSRCs) were successfully designed and synthesized by a facile one-step solvothermal method. Benefiting from the high conductivity and high specific surface area of carbon materials and the high specific capacity of nickel sulfide, as well as the stable nanostructures constructed by the synergistic effect of multiple components, the synthesized novel NSRCs nanohybrids exhibit impressive electrochemical performances, such as high specific capacity of 178.2 mAh g−1 (1604.1 F g−1) at 0.6 A g−1, excellent rate capability (57.3 % at 20 A g−1). Furthermore, the assembled hybrid supercapacitors (NSRC-24//AC HSC) with optimal NSRC-24 electrode and activated carbon (AC) electrode imparted a high energy density of 44.2 Wh kg−1 at a power density of 359.2 W kg−1 and excellent cycling stability (98.1 % capacity retention after 12,000 cycles at 5 A g−1). Thus, the synthesized novel NSRCs nanohybrids are highly promising candidates as advanced electrode materials for aqueous high-performance energy storage devices.

Construction and operation characteristics of a fully quantified low-carbon treatment process for old landfill leachate

The feasibility of utilizing a coagulation-flocculation/sedimentation-denitrification (DN)/partial nitrification (PN)-anaerobic ammonium oxidation (Anammox)-electrochemical oxidation was investigated to achieve cost-effective and fully quantified treatment of leachate from old landfills, which contains lower C/N, higher NH4+-N and refractory chemical oxygen demand (CODr). The results indicated that the coagulation-flocculation/sedimentation, which aimed to remove the CODr, not only improved the nitrogen conversion efficiencies of the following PN and Anammox by 17.5 % and 105 %, respectively, but also benefited the solid phase enrichment of PO43− and the energy consumption of subsequent advanced treatment. The optimal dose of perfluorochemical (PFC) was found to be 1200 mg/L. The optimal electrode plate spacing and current density of the electrochemical oxidation process were 25 mm and 350 A/m2, respectively, and advanced treatment of the chemical oxygen demand (COD) and total nitrogen (TN) in the wastewater was achieved within 2 h. After 190 d of operation, the effluent quality met the required discharge standards. This process has the advantage of realizing full quantified treatment of wastewater and has significant environmental benefits.

Nitrogen-doped carbon aerogel framework with in situ encapsulated ZrO2 nanoparticles as pseudocapacitive anode for phosphorus uptake

Phosphorus reduction is crucial for controlling eutrophication and protecting the aquatic environment. Nonetheless, traditional methods suffer from secondary pollution and high costs. Capacitive deionization (CDI) is a novel electrochemical approach for phosphorus removal, which is low-cost and environmentally friendly. Its performance is highly correlated with the electrode material. Herein, a novel nitrogen-doped carbon aerogel framework encapsulated with ZrO2 nanoparticles (ZrNC) was rationally fabricated and employed as an anode for phosphorus removal. The experimental results revealed that the N site and ZrO2 could enhance the physicochemical properties, electrochemical activity, and additional pseudocapacitive contribution, thus raising the phosphorus removal capacity. The optimal ZrNC-3 electrode demonstrated superior phosphorus capture (18.26 mg P/g), low energy consumption at 1.2 V (0.0256 kWh/m3 and 4.159 kWh/kg), outstanding phosphorus selectivity, and excellent stability. Mechanism investigation suggested phosphorus can form mono- or bi-dentate inner-sphere complexes (Zr–O–P) by ligand exchange with ZrO2 sites under an electric field and combined with unsaturated Zr sites and N species by electrostatic attraction. This study presents a promising conception for designing and applying metal oxide/carbon complexes in selective phosphorus uptake electrodes.

Design of cation (Mo) substituted transition metal dichalcogenide (NiSe2): NiMoSe2 electrode for high-performance asymmetric supercapacitors

High electrochemical activity and good stability in electrode materials are crucial to enhance supercapacitor performance. Cation-substituted bi-metal selenides have substantially higher electrochemical activity and capacity than mono-metal selenides. Cation substitution is a potential strategy to modify the structural and electrochemical properties of metal selenides. Here, the cation-substituted ternary nickel molybdenum selenide (NiMoSe2) nanoparticles were prepared using the facile solvothermal method, and utilised as pseudocapacitive electrodes for hybrid supercapacitors. The novel attempt of molybedum (Mo) substitution in the NiSe2 lattice, showed improved electrochemical performance owing to its enhanced charge transfer kinetics and ionic diffusion. The excellent faradic redox properties of the developed electrodes exhibit excellent pseudocapacitive behaviour in a potential window of 0.0 and 0.75 V. In a typical three-electrode system, the fabricated electrodes exhibit a specific capacitance of 480 Fg−1 at the current density of 5 Ag−1, which is greater than that of mono-metal selenide - NiSe2 nanoparticles. The optimum NiMoSe2 electrode retains 99.4 % of the initial specific capacitance over 5000 cycles at 5 Ag−1. Additionally, the fabricated asymmetric supercapacitor device (ASC) showed an energy density of 44.04 Whkg−1 at 2.1 kWh power density with exceptional device stability of 87.4 % retention after 15,000 cycles, demonstrating its exceptional performance and stability. Thus, this work demonstrates that metal selinides are promising supercapacitor electrode materials and the potential of cation substitution as a performance-improving strategy.

Role of electrode configuration and morphology in printed prothrombin time sensors

Patients on long-term anticoagulation therapy require frequent testing of prothrombin time/international normalized ratio (PT/INR) to ensure therapeutic efficacy. Point-of-care (POC) PT tests for at-home monitoring eliminate the burden of visiting the clinic, but realizing a cost-effective and robust at-home POC test for PT has remained elusive. Recent demonstrations of printed PT sensors show promise for addressing the cost concerns; however, the printed sensors have lacked quality control to ensure reliability between tests. In this work, on-chip redundancy is introduced with fully printed impedimetric PT sensors by incorporating simultaneous testing with a single fingerstick volume of blood (8 µL). The influence of electrode dimensions and composition were studied, revealing an optimal electrode spacing of 200 µm and an unexpected dependence on the morphology of the electrodes. Three distinct silver morphologies were studied: aerosol jet printed silver nanoparticles (AgNPs), aerosol jet printed silver nanowires (AgNWs), and evaporated silver (Ag). In general, AgNPs exhibited the best PT sensor performance, due to relatively low conductance and high porosity. Overall, the printed impedimetric PT sensor functionalization was improved by incorporating simultaneous testing and, when combined with a handheld control device, shows promise for leading to a system that overcomes the challenges of commercial PT/INR coagulometers.

Molybdenum-doped Ni–S nanostructure towards energy saving for hydrogen production coupling urea oxidation reaction

The growing trend of using energy from fossil fuel sources and the gradual reduction of these sources have caused concerns about future energy. Therefore, the need to use clean and renewable sources such as hydrogen has increased. The synthesis and design of effective electrocatalysts are important to generate hydrogen via urea electrocatalysis with the minimum required energy. In the present research, Ni–S nanostructures doped with molybdenum (Mo) supported on nickel foam substrates were synthesized by the facile one-step cyclic voltammetry (CV) method, and some of the efficient factors such as scan rate, number of cycles, and molybdenum concentration were optimized to generate the minimum required overpotential. The proposed electrode was used as a working electrode for urea-assisted electrochemical hydrogen production. The activity and electrocatalytic stability of the prepared electrodes were measured by linear sweep voltammetry (LSV), CV, Tafel polarization curve, and chronopotentiometry (CP) in 1 M NaOH + 0.33 M urea electrolyte. The results showed that the optimal electrode (50 mV/s scan rate and 10 cycles) has excellent electrocatalytic activity for hydrogen evolution reaction (HER) equal to −142.2 mV overpotential at a current density of 10 mA/cm2. In addition, the optimal electrode showed outstanding activity for the urea oxidation reaction (UOR) with a potential of 1.36 V (vs. RHE) to achieve a current density of 10 mA/cm2, which is due to the high surface-to-volume ratio, maximizing the number of active sites, good electrical conductivity, and synergistic effect of elements. On the contrary, to reach 10 mA/cm2, OER requires 1.55 (vs. RHE). In addition, an overall urea splitting cell voltage of only 2.52 and 2.76 V (vs. RHE) is needed to obtain 10 mA/cm2 current in urea and without urea-containing electrolytes, respectively. Therefore, replacing UOR with OER reduces the energy consumption of hydrogen production.

Regulating the Oxygen Vacancy and Electronic Structure of NiCo Layered Double Hydroxides by Molybdenum Doping for High-Power Hybrid Supercapacitors.

Amelioration of nickel-cobalt layered double hydroxides (NiCo-LDH) with a high specific theoretical capacitance is of great desire for high-power supercapacitors. Herein, a molybdenum (Mo) doping strategy is proposed to improve the charge-storage performance of NiCo-LDH nanosheets growing on carbon cloth (CC) via a rapid microwave process. The regulation of the electronic structure and oxygen vacancy of the LDH is consolidated by the density functional theory (DFT) calculation, which demonstrates that Mo doping narrows the band gap, reduces the formation energy of hydroxyl vacancies, and promotes ionic and charge transfer as well as electrolyte adsorption on the electrode surface. The optimal Mo-doped NiCo-LDH electrode (MoNiCo-LDH-0.05/CC) has an amazing specific capacity of 471.1mA h g-1 at 1 A g-1 , and excellent capacity retention of 84.8% at 32 A g-1 , far superior to NiCo-LDH/CC (258.3mA h g-1 and 76.4%). The constructed hybrid supercapacitor delivers an energy density of 103.3W h kg-1 at a power density of 750W kg-1 and retains the cycle retention of 85.2% after 5000 cycles. Two assembled devices in series can drive thirty LED lamps, revealing a potential application prospect of the rationally synthesized MoNiCo-LDH/CC as an energy-storage electrode material.