Fabrication Of Electrode Materials Research Articles

Advanced (Cu,Co)Se2 Nanocubes and Ti‐MXene Based Screen Printed Electrodes for High Performance Flexible Microsupercapacitors

AbstractNowadays, the demand for portable micro‐energy storage devices with high energy density and scalable printing with cost‐effective fabrication for microsupercapacitors (MSC) are essential. Furthermore, the urgent need for this high‐performance MSC to meet all industrial sector requirements are very challenging. Herein, the screen printable MSC with high energy density is demonstrated by using copper hexacyanocobaltate (CuHCCo) derived (Cu,Co)Se2 nanocubes as the positive electrode and Ti‐MXene (Ti3C2Tx) as the negative electrode. The prepared battery type (Cu,Co)Se2 nanocubes greatly enhance the high electrochemical activity and active surface area. As a result, it delivers a high specific capacity of 602 C g−1 at the current density of 1 A g−1. The fabricated screen printable asymmetric MSC has enhanced ion‐to‐electron transfer in printable microelectrodes with numerous electrochemical active sites and delivered the high areal capacitance of 58 mA cm−2 at the current density of 1 mA cm−2 with a wide potential window. The device gives a high energy density of 8.06 µWh cm−2 and a high power density of 5 mW cm−2. These results demonstrate the new strategies of fabricating electrode materials in screen printable asymmetric MSC and show promising in microscale energy storage devices in the miniaturized devices with sustainable self‐powered compatibility.

In-situ synthesis of synergistic ZnMn2O4/MnOOH nanocomposite as a cutting-edge pseudocapacitive electrode material for all-solid-state asymmetric supercapacitors

Currently, there has been a growing interest in constructing metal oxide composite structures through the in-situ synthesis method, especially for fabricating electrode materials for supercapacitors. This approach offers several advantages, such as improved contact between different materials, enhanced conductivity, efficient ion diffusion, and better overall electrochemical performance. This work investigates the synthesis of zinc manganese oxide and manganese oxyhydroxide (ZnMn2O4/MnOOH) composite using a solvothermal method. The structure, surface morphology, and composition of the ZnMn2O4/MnOOH composite were elucidated using standard physicochemical characterization techniques where the presence of ZnMn2O4 and MnOOH phases was confirmed and the ZnMn2O4/MnOOH nanocomposite behaved as a pseudocapacitive electrode with a notable specific capacitance of 1039.2 F g⁻1 at a current density of 1 A g⁻1. When subjected to a 10-fold increase in current density, the ZnMn2O4/MnOOH electrode maintained 50 % of its initial capacity, registering 513.4 F g⁻1. Additionally, the electrode showcased excellent cyclic stability, preserving 95 % of its initial capacity after 5000 cycles at 10 A g⁻1. Moreover, the constructed ZnMn2O4/MnOOH//activated carbon (AC) asymmetric supercapacitor (ASC) device attained a high energy density of 29.45 Wh kg⁻1 at a power density of 1384.5 W kg⁻1. The results confirm that the ZnMn2O4/MnOOH composite, prepared in a single synthesis step, shows great potential as a phenomenal pseudocapacitive electrode for energy storage applications.

Ruthenium-based microstructures modified by gold particles as composite electrode material for non-enzymatic epinephrine detection

A simple and efficient technique for voltammetric enzymeless detection of epinephrine (EP) was proposed. In this technique, we applied hierarchical Ru-based electrode modified by Au nano- to micro-sized particles that was fabricated using laser-assisted synthesis. The cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were employed to characterize electrochemical properties of the fabricated electrode material. For EP detection, we obtained two DPV calibration curves that were linear in the range of 0.05–5 μM and 5–500 μM. The highest sensitivity (45.0 μA μM−1 cm−2) and the lowest detection limit (6.4 nM) were observed for the first linear range, whereas the estimated sensitivity and limit of detection for the second linear range were 2.0 μA μM−1 cm−2 and 18.7 nM, respectively. We also demonstrated that the proposed technique can be used for selective EP determination in the presence of such common interfering analytes as ascorbic acid and dopamine. The results of this study can be potentially used for development of low-cost voltammetric sensor platforms for non-enzymatic epinephrine detection.

Comparative Investigation of Water-Based CMC and LA133 Binders for CuO Anodes in High-Performance Lithium-Ion Batteries.

Transition metal oxides are considered to be highly promising anode materials for high-energy lithium-ion batteries. While carbon matrices have demonstrated effectiveness in enhancing the electrical conductivity and accommodating the volume expansion of transition metal oxide-based anode materials in lithium-ion batteries (LIBs), achieving an optimized utilization ratio remains a challenging obstacle. In this investigation, we have devised a straightforward synthesis approach to fabricate CuO nano powder integrated with carbon matrix. We found that with the use of a sodium carboxymethyl cellulose (CMC) based binder and fluoroethylene carbonate additives, this anode exhibits enhanced performance compared to acrylonitrile multi-copolymer binder (LA133) based electrodes. CuO@CMC electrodes reveal a notable capacity ~1100 mA h g-1 at 100 mA g-1 following 170 cycles, and exhibit prolonged cycling stability, with a capacity of 450 mA h g-1 at current density 300 mA g-1 over 500 cycles. Furthermore, they demonstrated outstanding rate performance and reduced charge transfer resistance. This study offers a viable approach for fabricating electrode materials for next-generation, high energy storage devices.

Key role of adsorption site abundance in the direct electrochemical co-detection of estradiol and dopamine

Estradiol (E2) is a hormone that influences various aspects of women’s health. Beyond its reproductive functions, E2 impacts neurotransmitter systems such as dopamine (DA). Vertically aligned carbon nanofibers (VACNFs) have shown good sensitivity, selectivity against ascorbic acid (AA) and uric acid (UA), biocompatibility, and reduced fouling in DA sensing. In this study, we explore the use of Ti-Ni-CNF electrodes with CNFs grown for 5 min and 30 min for the direct electrochemical co-detection of E2 and DA. The longer growth time led to a 142% increase in average CNF length and a 36% larger electroactive surface area. In E2 detection, the electrodes demonstrate a wide linear range of 0.05–10 µM and sensitivity of 0.016 and 0.020 µA/µM for Ti-Ni-CNF-5 min and Ti-Ni-CNF-30 min, respectively. The sensor performance remains largely unaffected even in the presence of other steroid hormones such as progesterone and testosterone. Co-detection of equimolar E2 and DA shows promising peak separation of 0.34 ± 0.01 V and repeatability after 10 measurements. A notable improvement in the E2/DA peak current ratio, from 0.53 ± 0.07 to 0.81 ± 0.16, was achieved with the increased CNF length. Our results demonstrate the influence of adsorption sites in electrochemical detection, especially for analytes such as E2 and DA that both rely on adsorption for oxidation. While detecting small and fluctuating physiological concentrations remains a challenge, these findings can be used in choosing and fabricating electrode materials for more accurate and accessible continuous hormone measurements, including the possibility of multianalyte sensing platforms.Graphic abstract

High volumetric performance of functional carbon material enabled by co-pyrolysis of mango branches and Faradaic active N-enriched doping

Restricted by the poor volumetric performance, biomass-based supercapacitors are challenging to meet the rapid development of miniaturization and portability of energy storage devices, and the Faraday active nitrogen-doping strategy proves to be an efficient approach to address this concern. This study successfully synthesizes functional carbon materials with significant Faraday activity through a straightforward and environmentally friendly co-pyrolysis method. Mango branches served as the primary raw material, NH4B5O8∙4H2O acted as a template, and NH4Cl and NH4B5O8∙4H2O were utilized as the multiple nitrogen-enriched agents. A surface micro-NH3 environment can be achieved by modulating the addition of NH4Cl, and the decomposed NH3 is adsorbed on the biomass surface by the electrostatic adsorption of NH4B5O8∙4H2O. MA1.5N1.5-T700 showcases a compact self-supported structure with micro/mesopores, boasting a substantial nitrogen content of 2.95 %. It achieves a notable volumetric capacitance of 320 F/cm3 (368 F/g) at 0.5 A/g and maintains an exceptional rate performance of 72.9 % at 20 A/g. The constructed symmetrical supercapacitor also reveals an ultra-high energy density of 13.01 Wh/L (14.95 Wh/kg) and an impressive capacitance retention of 94.03 % undergoing 10,000 cycles. This study offers theoretical insights into fabricating electrode materials for high volumetric energy density supercapacitors through the pyrolysis of forestry waste.

A Precursor-Derived Ultramicroporous Carbon for Printing Iontronic Logic Gates and Super-Varactors.

A liquid precursor for 3D printing ultramicroporous carbons (pore width <0.7nm) to create a novel in-plane capacitive-analog of semiconductor-based diodes (CAPodes) is presented. This proof-of-concept integrates functional EDLCs into microstructured iontronic devices. The working principle is based on selective ion-sieving, controlling the size of the electrolyte ions, and the nanoporous sieving carbon's pore size. By blocking bulky electrolyte ions from entering the sub-nanometer pores, a unidirectional charging characteristic with controllable ion flux is achieved, leading to diodic U-I characteristics with a high rectification ratio. The liquid precursor approach enables successful printing of miniaturized in-plane CAPodes. A combination of inkjet and extrusion printing techniques with suitable inks is explored to fabricate electrode materials with engineered porosity. Deliberate fine-tuning of the ultramicroporous carbon's porosity and surface area is achieved using a customized carbon precursor and CO2 etching techniques. Electrochemical evaluation of the printed CAPodes demonstrates successful miniaturization compared with macroscopic film assembly. 3D manufacturing and miniaturization allow for the integration of CAPodes into logic gate circuits (OR, AND). For the first time, these switchable devices are used as variable capacitors in a high-pass filter application, adjusting the cut-off frequency of applied alternating voltage analogous to an I-MOS varactor.

Development of cost-efficient BaMnO3/rGO nanocomposite as electrode for energy storage applications in supercapacitor

The excessive fossil fuels utilization leads to environment contamination along with energy loss and is becoming a serious issue in these days. Therefore, to handle these energy issues, alternative sources and energy-storing devices like supercapacitors are in demand in the modern era. Many perovskites have been used in supercapacitors as electrode material but because of its less cyclic stability and poor conductivity, rGO mixed to enhance the electrochemical properties of perovskite. Therefore, we used rGO with BaMnO3 to fabricate BaMnO3/rGO nanocomposite through hydrothermal method for supercapacitor electrodes. After different physical analyses, BaMnO3/rGO nanocomposite showed remarkable electrode applications having distinct nanostructure with increased surface area, conductivity, crystallinity and improved morphology. The electrode material demonstrated a substantial surface area (54.32 m2 g−1) measured by Brunner–Emmett–Teller analysis, while scanning electron microscopy results showed that BaMnO3 dispersed tightly on rGO. The fabricated electrode material demonstrated a specific capacitance of 1359.85 F g−1, energy density of 78.62 Wh kg−1 and power density of 322.6 W kg−1 at 1 A g−1 current density. Furthermore, the Nyquist plot revealed a low value of Rct (0.04 Ω), indicating good electrical conductivity, while the material displayed stability even after 5000th cycle. This work revealed that, such extraordinary and outstanding qualities of BaMnO3/rGO nanocomposite provide a viable option for use in next-generation supercapacitor applications along with high stability and cost effectiveness.

In-situ synthesis of coral reef-like synergistic zinc cobalt oxide and zinc manganese oxide composite as a battery-type electrode material for supercapacitors

Recently, in-situ preparation of metal oxide composite structures has gained much importance in fabricating electrode materials for energy storage and conversion devices because of its advantageous properties of beneficial interfacial contact, high conductivity, good synergism, short ion diffusion distance, better electrochemical performance, etc. Binary transition metal oxides (BTMOs) are given great attention for their significant electrochemical performances over primary MOs because of the two metal ions with different valent states for the redox reactions. In this study, we synthesize zinc cobalt oxide (ZnCo2O4) and zinc manganese oxide (ZnMn2O4) composite via a solvothermal synthetic method. The existence of both phases is identified using an X-ray diffraction analysis (XRD). The unique coral reef-like structures of the composite electrode are analysed via field emission scanning electron microscopy, and the nanostructure was identified using transmission electron microscopy. The X-ray photoelectron spectroscopy confirms the surface oxidation states of the composite and supports the XRD analysis. The synergetic composite electrode provides a large surface area of 50.86 m2 g−1 with many pores. The composite electrode has a specific capacity of 250 C g−1 at 1 A g−1. The ZCO/ZMO composite demonstrated impressive stability, retaining a specific capacity of 180 C g−1 at 6 A g−1 over 5000 cycles.

ZIF-67 MOF-Derived Mn3O4 @ N-Doped C as a Supercapacitor Electrode in Different Alkaline Media.

Transition-metal oxide has been identified as an auspicious material for supercapacitors due to its exceptional capacity. The inadequate electrochemical characteristics, such as prolonged cycle stability, can be ascribed to factors, such as low electrical conductivity, sluggish reaction kinetics, and a deficiency of active sites. The transition-metal oxides derived from the MOF materials offer a larger surface area with enriched active sites and a faster reaction rate along with good electrical conductivity. The manganese (Mn)-based metal-organic framework (MOF)-derived materials were produced using the pyrolysis method. Zeolitic imidazolate frameworks (ZIF-67) were fabricated in water at ambient temperature with the aid of triethylamine. Multiple techniques were used to examine the characteristics of the fabricated electrode materials. The influence of the electrolyte on the electrochemical activity of the Mn3O4@N-doped C electrode materials was determined in KOH, NaOH, and LiOH. For manufacturing of "Mn3O4@N-doped C", ZIF-67 was used as a precursor. The capacitive performance of the Mn3O4@N-doped C electrode increased as a result of nitrogen-doped carbon; after 5000th cycles, the electrode retained an excellent rate capability and a high specific capacitance (Cs) of 980 F g-1 at 1 A g-1 under 2.0 KOH electrolyte in a three electrode system. The carbonized manganese oxide displays also had a high Cs of 686 F g-1 in two electrode systems in 2.0 M KOH. Materials made from MOFs show promise as capacitive materials for applications in energy conversion storage owing to their straightforward synthesis and strong electrochemical performance.

GO induces ZIF-8 to produce hollow nanobox CoSe2@ZnSe/rGO for high-performance supercapacitors

Reasonable use of graphene oxide (GO) conductive network structure can enhance the charge storage and transfer of electrode materials. In this paper, the deposition of ZIF-8 on the surface of graphene oxide (GO) was induced by Cokendall effect and selenization, and the unique matching method of Co2+ and ZIF-8 was used to obtain CoSe2@ZnSe/rGO electrode materials with reduced graphene oxide (rGO) as the growth substrate. The capacity of a three-electrode test with a current density of 1.0 A g−1 is as high as 2075.43 F g−1, and the capacity retention rate is 83.09 % after the circulation of 10,000 times. The assembled asymmetric supercapacitor GCZS-2//AC has a high power density of 1279.95 W kg−1 at an energy density of 85.33 Wh kg. The improvement of electrochemical properties benefits from the unique structure structure of the unique hollow nano box skeleton. In addition, DFT theoretical calculations show that CoSe2@ZnSe grown on rGO has stronger charge mobility and conductivity. This work provides a strategy for fabricating electrode materials with unique structures using rGO as a growth template.

Zn doping induces rich oxygen vacancies in δ-MnO2 flower-like nanostructures for impressive energy density coin cell supercapacitor

In this work, Zn-doped δ-MnO2 (ZnMO) flower-like nanostructures on carbon fibers are synthesized by one-pot hydrothermal method. It is found that insertion of Zn ions induces oxygen vacancy defects, increase in active sites and conductivity of δ-MnO2 (MO) structure. These features making ZnMO structure an excellent candidate for the fabrication of electrode material for supercapacitors. It has been revealed that ZnMO@CC electrode delivered an enhanced specific capacitance of 667 F g−1 at a current density of 1 A g−1 as compared to the pristine δ-MnO2 and previously reported nanostructures. The developed asymmetric coin cell supercapacitor (ZnMO//AC) obtained a specific capacitance of 116 F g−1 at 1 A g−1 and achieved an outstanding energy density of 71.5 Wh kg−1 at a power density of 1067.1 W kg−1. Moreover, the device retains its initial capacitance of 92 % after 8000 cycles at 8 A g−1. These results suggest that ZnMO could be an emerging electrode material for the fabrication of high-performance supercapacitors for practical applications. This research hunts for new visions for the preparation of MnO2-based material by doping strategy for energy storage applications, especially supercapacitor.

Electrochemical Behaviour of Ultrasonic Probe Assisted Nickel Pyrophosphate (Ni2P2O7) Nanosheets for Supercapacitor Applications

New materials and synthesis strategies are needed to achieve better electrochemical performance. In this context, we developed a Ni2P2O7 Nanosheets (NNS) as a new classical-type active electrode using a simple and low-cost method. Crystal phase, chemical structure, and morphology of the sample were inspected by X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), and Field Emission Scanning Electron Microscopy (FESEM) - Energy Dispersive Spectroscopy (EDS) analysis, respectively. As prepared electrode material was confirmed with monoclinic phase and nanosheet morphology identified from XRD and FESEM analysis, respectively. Various types of electrochemical approaches, such as CV, GCD, Cycling stability, and EIS applied in 2 M KOH electrolytes to investigate supercapacitive behaviour. As fabricated electrode material portrays satisfied specific capacitance (Cs) of 514.7F/g at a scan rate of 1 mV/s along with the excellent cyclic ability of 80 % retention upon 3000 continuous CV cycles, good rate capability in the extended potential window of 1 V. The GCD tests revealed remarkable specific capacity (462C/g) and exceptional energy density (64 Wh/Kg). Moreover, electrode material displayed impressive columbic efficiency as to be 77 % and 51 % at lower and higher current densities, respectively. These notable merits suggest that our designed Nanosheets (NNS) sample is the best opportunity for the development of sustainable supercapacitor devices.

Fabrication of Electrode Material for Textile-Based Triboelectric Nanogenerators: Research of the Relationship between Output Performance and Dielectric Material Strain.

In this work, a textile-based triboelectric nanogenerator (TENG) device was developed through electroless plating technology to prepare electrode material. Hydrophilic groups on the fiber surface are able to absorb Ag+, which could play a role in the center of a catalyst to reduce Cu2+ to fabricate Cu-coated cotton toward the fabrication of TENG electrode material. The TENG device established admirable performance and good stabilization, and a maximum voltage at 9.6 V was detected when the stress and strain on the polydimethylsiloxane layer are 82.6 kPa and 5.8%, respectively. In addition, the relationships among device properties and strain/thickness of dielectric materials have been explored in depth as well. The output voltage of the device increases gradually with the enhancement of dielectric strain and stress. As expected, the TENG as-fabricated device was installed to various physical behaviors to illustrate the harvesting of power of knee-jerk movements.

Mechanochemical enhancement in electrode materials via silver-embedded reduced graphene oxide and cobalt oxide nanostructure for supercapacitor applications

This study delves into the intricate domain of mechanochemical synthesis, employing a developed approach for the fabrication of electrode materials. The method involves the incorporation of silver nanoparticles into a two-dimensional matrix of reduced graphene oxide (RGO) combined with cobalt oxide nanostructures, yielding a zero-dimensional cobalt oxide@RGO.Ag nanocomposite. A comprehensive suite of material characterization techniques, including XRD, SEM, EDX, TEM, XPS, and BET, was used to investigate the synthesized materials. Concurrently, extensive electrochemical investigations, incorporating cyclic voltammetry (CV), galvanic charge–discharge (GCD), electrochemical impedance spectroscopy (EIS), and retention analyses, are applied to the constructed electrochemical cell. The resulting RGO.Ag@Co3O4 nanocomposite exhibits a remarkable specific capacitance of 371.2 F g−1 at a scan rate of 5 mV s−1. In addition, energy density (Ed) and power density (Pd) values of 21.6 Wh/kg and 997 W/kg, respectively, are achieved at a current density (Cd) of 0.5 A g−1.

Rationally designed CeO2 decorated Ti3C2 MXene interface for efficient water splitting and enhanced supercapacitor performance

MXenes serve as competent electrodes for applications such as energy storage and conversion owing to their unique characteristics, which include substantial surface area, excellent conductivity, abundant surface-terminating groups, and high hydrophilicity. However, MXene nanosheets exhibit a pronounced tendency to restack via Van der Waals force, hindering the active sites and resulting in sluggish electronic and ionic kinetics. This phenomenon limits the capabilities, processability, and overall performance of MXene. In this study, CeO2 is utilized as an interlayer spacer for the Ti3C2 MXene substrate, providing a promising noble metal-free multifunctional electrode. The Ti3C2/CeO2 composite, synthesized via the hydrothermal method, efficiently mitigates restacking while exhibiting excellent conductivity, substantial surface area, and enhanced kinetics. The as-synthesized catalysts undergo diverse physiochemical characterizations and electrochemical measurements to understand their properties and potential multiapplications. The fabricated electrode material, Ti3C2/CeO2, shows excellent specific capacitance of 1908.5 Fg−1 at 1 Ag−1 in a three-electrode setup using 3 M KOH as electrolyte. It has a capacitive retention of 91% even after 4000 cycles. Besides, Ti3C2/CeO2 also functions as a proficient electrode material for overall water splitting, having a lower overpotential of 178 mV and 350 mV for hydrogen and oxygen evolution reactions, respectively, at a current density of 10 mAcm−2. It also displays a lower cell voltage of 1.78 V to obtain a current density of 10 mAcm−2. This study introduces the multi applications of a well-designed interface between Ti3C2 layers and CeO2 within the realm of electrochemical energy storage and conversion.

Exploring the potential of polyaniline-calcium titanate (PANI-CaTiO3) nanocomposites in supercapacitors: Synthesis and electrochemical investigation

This work presents the simple approach for the synthesis of CaTiO3 incorporated polyaniline nanocomposites (PANI- CaTiO3) by facile in-situ oxidative polymerization route, to be used as electrode materials for supercapacitors (SCs). The developed samples were evaluated using several analytical methods viz. X-ray diffraction (XRD), thermogravimetric analysis (TGA), Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, field emission scanning electron microscopy (FESEM), and Brunauer-Emmett-Teller analysis (BET). The electrochemical performance of the prepared nanocomposites for energy storage application was evaluated by cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS) in 3 M of KOH as an electrolyte. In comparison to pristine PANI, which demonstrated a specific capacitance of 257 Fg−1, and pure CaTiO3, which exhibited a specific capacitance of 142 Fg−1, the results of cyclic voltammetry (CV) for PANI-35 % CaTiO3 nanocomposites revealed a higher specific capacitance of 966 Fg−1 at 10 mV/s sweep rate. The highest energy density and power density for the PANI-35 % CaTiO3 nanocomposites were shown by galvanostatic charge-discharge (GCD) measurements to be 58.14 Whkg−1 and 3.2 kWkg−1, respectively, at a higher specific capacitance value of 984.21 Fg−1 at 6.86 Ag−1 current density. Additionally, the straight line in low frequency Nyquist plots was linked to the low electrolyte diffusion (Warburg) resistance within the electrode and ions diffusion into the electrode surface, confirming the CV results. Moreover, this study proposes an innovative research concept for the fabrication of electrode materials specifically designed for supercapacitors.

In-situ growth of Cu nanoparticles-polybenzidine over GO sheets onto graphite sheet as a novel electrode material for fabrication of supercapacitor device

Introducing and use of novel conductive polymers and their composites for use in the supercapacitor industry is very important. In this study, for the first time, the doping of copper nanoparticles on conductive poly benzidine polymer (Cu-PB) deposited on graphene oxide sheets (GO) created on graphite sheets as a result of the anodizing process (AGs) has been introduced as a novel electrode. Cu-PB/GO/AGs electrode was fabricated simply by anodizing the graphite sheet followed by in-situ polymerization of poly benzidine and finally doping copper nanoparticles on the surface of the electrode. The surface morphology and chemical structure of the Cu-PB/GO/AGs electrode were examined by ATR-IR, XRD, EDX, and FE-SEM analysis. The capacitive behavior of the fabricated electrode was evaluated by electrochemical techniques such as cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS) and the results showed that the Cu-PB/GO/AGs electrode has an excellent capacitive capacity of 777.77 F g−1 at 1 A g−1 without ohmic drop in 1 M H2SO4 solution. Finally, the practical application of Cu-PB/GO/AGs electrode was evaluated by fabricating a symmetrical solid-state supercapacitor device and the results showed that fabricate device has 83.02 % cyclic stability after 10,000 charge-discharge cycles and a capacitance of 305.55 F g−1 at 0.5 A g−1 that proven the Cu-PB/GO/AGs electrode is a promising candidate for use in supercapacitor industries.

Strategies for Sustainable Fuel Production Via Photoelectrochemical Synthesis

Developing sustainable energy is highly imperative for humankind owing to the drastic rise in world population and the proportional rise in energy demand at the expense of energy consumption. Various efforts have been made to explore, generate, store, and utilize renewable energy to replace fossil fuels. Among them, solar energy is considered an alternative to fossil fuels because it is inexhaustible, clean, cost-effective, and versatile. Interestingly, this prime source provides massive energy that is high enough (1.9 × 108 TWh/yr) to counterattack global energy consumption (1.3 × 105 TWh/yr).Photoelectrochemistry has been considered a promising route to harness this incredible energy by producing sustainable energy fuels and carriers such as hydrogen, hydrocarbon, and ammonia. PEC systems have the great advantages of simple process steps and very low environmental burdens. However, this technology must overcome many challenges regarding commercial applications, particularly in fabricating electrode materials for PEC water splitting.One of the most important challenges to overcome this problem is discovering efficient catalysts for implementing photoelectrochemical (PEC) fuel production. A critical requirement for outstanding catalysts is an ability to boost the kinetics of a chemical reaction and durability against electrochemical and photo-induced degradation. Moreover, the charge-separation and transfer mechanism are the two paramount properties to consider while designing photoelectrodes. Briefly, the semiconductor materials to be used in PEC water splitting must possess a conduction band potential more negative than the reduction edge of hydrogen and a valence band potential positive to actuate water oxidation. In practice, the photocurrent density and solar-to-hydrogen (STH) efficiency of the n-type semiconductors are far behind the theoretical values.To address this critical and long-standing technical barrier, I have focused on an intense search for efficient, durable, and inexpensive alternative catalysts with moderate band gap, efficient charge excitation-separation property, and high solar energy conversion efficiency for photoelectrochemical systems of water splitting, hydrocarbon conversion, and ammonia production. Keywords : Photoelectrochemistry, Sustainable Energy, Water Splitting, Ammonia synthesis, Urea synthesis, Hydrocarbon

Enhanced electrochemical performance of in situ polymerized V2O5-PANI nanocomposites and its practical application confirmation by assembling ionic liquid as well as solid state-based supercapacitor device

In the present study, in situ polymerization of anilinium hydrochloride over V2O5 was used to prepare PANI nanocomposites with varying weight percentage of V2O5 (10, 20 and 30 wt%). V2O5 nanoparticles were synthesized using a simple chemical approach and their purity was confirmed through Rietveld refinement. It confirmed the advantageous electrochemical activity of V2O5 with a higher oxidation state of vanadium (V+5), enabling efficient electron storage. For fabricated electrode materials, the pair of redox peaks as well as their shape in CV suggests the faradic pseudocapacitive properties. Among all prepared electrodes, 20 wt% V2O5-PANI (PV2) nanocomposite demonstrates maximum specific capacitance of 820.5 Fg−1 at a current density of 1 Ag−1 with decent capacitive retention of 88 % after 1000 charge–discharge cycles. PV2 electrode also has a lower charge transfer resistance (Rct) of 0.5 Ω and lesser solution resistance (Ro) of 0.31 Ω in 6 M KOH electrolyte which is also responsible for good electrochemical performance. The higher capacitance value and decent stability of PV2 confirmed its ordered structure with more active sites shown through FESEM, which significantly contributes to efficient ion and electron transfer. In addition, the symmetric supercapacitor configuration of PV2 electrodes exhibits good energy and power densities of 4.6 Wh kg−1 and 80.7 W kg−1, respectively. Finally, the ignition of a red LED using three PV2//PV2 symmetric devices connected in series underscores its potential to advance energy storage applications.