Capacitance Values Research Articles

Frequency-polarization multiplexing reflective metasurface for orbital angular momentum generation

Frequency-polarization multiplexing metasurfaces (FPMMSs) capable of generating vortex beams carrying orbital angular momentum (OAM) have facilitated the actualization of high information capacity in optical and microwave communication. However, poor frequency controllability and the deficiency of theoretical methodology for frequency modulation of meta-atom remain challenges for existing FPMMSs with orthogonal linear polarization. In this work, a strategy to customize the operating band of the “I”-shaped meta-atom (ISMA) based on phase analysis of the equivalent circuit is proposed. A frequency modulation factor is introduced to adjust the operating band of the ISMA over a wide range based on the relationships between element geometry parameters, capacitance and inductance values in the equivalent circuit model, and the reflected phase of ISMA-type meta-atom. Then, a dual-band dual-polarized meta-atom is proposed by placing subunits operating at different bands cross-orthogonally, allowing the subunits to modulate the phase independently. A dual-band dual-polarized dual-mode OAM beam generator is designed and constructed as a proof-of-concept to verify the methodology. The measured results are in excellent agreement with the simulations. The proposed methodology for customizing frequencies establishes the groundwork for the implementation of OAM-based FPMMSs for secure and high-capacity communication in 6G massive-MIMO systems.

Cobalt‐based zeolitic imidazole framework derived hollow Co3S4 nanopolyhedrons for supercapacitors

Transition metal sulfides with designed nanostructures are expected to provide superior electrochemical performance when used as electrode materials for pseudocapacitors compared to their oxide counterparts. In this paper, hollow Co3S4 dodecahedra were successfully prepared using cobalt‐based zeolite imidazolium skeleton (ZIF‐67) as the precursor and thioacetamide (TAA) as the sulfur source combined with a facile one‐step vulcanization process. The hollow cavity structure not only shortens the carrier transport distance but also provides a higher specific surface area and abundant active sites, which promotes an efficient mass transfer process. In addition, the one‐step synthesis of hollow Co3S4 has greater advantages than the one‐step synthesis in terms of cost control and process simplification. The specific capacitance of the produced hollow Co3S4 nanopolyhedra was 668 F/g at 1 A/g and remained at 353 F/g at 10 A/g when used as a pseudocapacitor electrode, demonstrating its superior multiplication capability. In addition, the capacitance retention is 86.4% after 5000 cycles at 4 A/g, indicating its long cycle stability. Notably, employing commercial activated carbon as negative electrode and the as‐prepared hollow Co3S4 polyhedrons as positive electrode, the assembled asymmetry supercapacitor device delivers a high energy density of 20.7 Wh/kg at a power density of 716 kW/kg. The capacitance value of the device remains up to 81.4% after 2000 charging/discharging cycles. The simple synthesis process opens new opportunities to develop advanced hollow nanostructures exhibiting potential for various applications.

Boosting electrochemical energy storage properties of SrGd2O4 through Yb3+ and Tm3+ rare earth ion doping

Electrochemical supercapacitors represent advanced energy storage devices that excel in the swift storage and delivery of electrical energy, effectively bridging the gap between conventional capacitors and batteries. The present work, aimed to investigate charge storage properties of SrGd2O4 and rare earth ions Yb3+ and Tm3+ doped in SrGd2O4. Both materials were prepared via simple sol-gel synthesis and characterized by XRD, XPS, and FE-SEM with EDS. Characterization confirmed the presence of Tm3+ and Yb3+ in the SrGd2O4 matrix with a uniform distribution of elements. The charge storage behavior of pure SrGd2O4 and SrGd2O4:Yb4Tm1 in various electrolytes was thoroughly explored. Large electrochemical potential windows were shown by both electrode materials in aqueous 6 M KOH (1.7 V), which is essential for supercapacitors to achieve high specific energy. Furthermore, SrGd2O4:Yb4Tm1 demonstrated a substantially more pronounced charge storage effect in 6 M KOH electrolyte, with almost double times higher specific capacitance values compared with an un-doped SrGd2O4 sample. The main impact on the electrochemical window had matrix SrGd2O4, while the main impact on specific capacitance had rear earth dopants (Yb3+ and Tm3+). Improved charge storage characteristics of SrGd2O4:Yb4Tm1 were also evident through a notable reduction in overall resistance observed in electrochemical impedance spectroscopy experiments. Concerning the two-electrode GCD measurements, the SrGd2O4:Yb4Tm1 electrode in 6 M KOH showed a specific capacitance of 143 F g−1, with the specific energy of 12.5 Wh kg−1 at 0.6 A g−1. These findings demonstrate the potential of rare earth ion doping in enhancing the energy storage properties of SrGd2O4, offering promising avenues for the development of high-performance supercapacitors.

Pore size, conductivity and surface area effects of rGO/ZnO/PTh hybrid nanocomposite for supercapacitors

This paper presents an easy and low-cost synthesis of reduced graphene oxide (rGO) and Zinc oxide (ZnO) as binary nanocomposite (rGO/ZnO) and rGO, ZnO and polythiophene (PTh) as ternary hybrid nanocomposite (rGO/ZnO/PTh). Firstly, graphene oxide (GO) was synthesized from modified Hummers method. And it was reduced by microwave-assisted method to form as reduced graphene oxide (rGO). Polythiophene (PTh) was chemically synthesized to comparison with nanocomposites. Secondly, binary nanocomposite of rGO/ZnO were synthesized by probe-sonication method. Thirdly, rGO/ZnO/PTh hybrid nanocomposite was chemically synthesized using FeCl3 as an oxidant. All these materials were examined by many different techniques, such as FTIR-ATR, SEM-EDX, TGA-DTA, BET, Four-point probe analysis, cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS) analysis. The average pore width, conductivity and specific capacitance values were comparatively investigated to understand these effects on electrochemical performances of supercapacitor devices.The highest specific capacitance (Csp) was obtained as Csp = 430 F/g for rGO/ZnO nanocomposite at a scan rate of 2 mV/s. Moreover, it also shows a good charge/discharge performance (up to 1000 cycles) with 98.43 % capacitance retention at a scan rate of 100 mV/s by CV method. However, GCD and EIS methods have showed the highest specific capacitances as Csp = 85.6 F/g at 10 A/g, and Csp = 25.8 F/g for both hybrid rGO/ZnO/PTh nanocomposites, respectively. In addition, a new equivalent circuit model [R1(C1(Rct(C2R2)))] was suggested to interpret the EIS data for supercapacitor devices. As a results, both binary and ternary nanocomposites may be recognized as electrode materials with three different methods (CV, GCD and EIS) in supercapacitor applications.

Self-Frequency Tracking for Fixed-Ratio Switch-Capacitors in Data Center Application without Extra Sensors

As research into data centers progresses, the importance of resonant switched-capacitor converters in power supply design becomes more evident. Practical applications reveal that the values of resonant capacitors and inductors may deviate from their nominal values due to various factors, leading to resonant frequency instability. This instability poses a challenge to power electronics technology, affecting system reliability and performance. This paper analyzes the effect of frequency deviation on system functionality, identifies the relationship between output voltage and switching frequency, and proposes a self-tracking frequency strategy to address this issue. Through experimental validation, this approach shows that it maintains synchronization between switching and resonant frequencies, reducing losses associated with frequency misalignment. Simulation and experimental results validate the converter’s stable operation and its ability to achieve zero-voltage and zero-current switching.

Exploring Mixed Ionic-Electronic-Conducting PVA/PEDOT:PSS Hydrogels as Channel Materials for Organic Electrochemical Transistors.

Here, we report the preparation and evaluation of PVA/PEDOT:PSS-conducting hydrogels working as channel materials for OECT applications, focusing on the understanding of their charge transport and transfer properties. Our conducting hydrogels are based on crosslinked PVA with PEDOT:PSS interacting via hydrogen bonding and exhibit an excellent swelling ratio of ~180-200% w/w. Our electrochemical impedance studies indicate that the charge transport and transfer processes at the channel material based on conducting hydrogels are not trivial compared to conducting polymeric films. The most relevant feature is that the ionic transport through the swollen hydrogel is clearly different from the transport through the solution, and the charge transfer and diffusion processes govern the low-frequency regime. In addition, we have performed in operando Raman spectroscopy analyses in the OECT devices supported by first-principle computational simulations corroborating the doping/de-doping processes under different applied gate voltages. The maximum transconductance (gm~1.05 μS) and maximum volumetric capacitance (C*~2.3 F.cm-3) values indicate that these conducting hydrogels can be promising candidates as channel materials for OECT devices.

Supercapacitor Performance of Sulfonyldibenzene Derivative-Functionalized Graphene Aerogel.

3D aerogels incorporating functionalized reduced graphene oxide (SUL/rGO) were prepared as a hydrothermal method utilizing graphene oxide (GO) and a sulfonyldibenzene derivative (SUL) as raw materials. The aromatic compound SUL, which contains hydroxyl and sulfonyl groups, was bonded to reduced graphene oxide (rGO) through π-π connections. The obtained composite material exhibited porosity within its structure with improved hydrophilicity, along with excellent electrochemical characteristics. This improvement was ascribed to the specific rGO structure, as well as the pseudocapacitance inherent in SUL, both of which synergistically contribute to improvement in the characteristics of the prepared electrode materials. Also, an analysis was performed employing density functional theory from which the density of states and adsorption energy of SUL on the surface of rGO were computed to further investigate the charge storage process within the prepared composite. The prepared SUL/rGO-2 electrode exhibited the highest specific capacitance value of 388 F/g at a current density equal to 1 A/g. The constructed symmetrical supercapacitor, SUL/rGO-2//SUL/rGO-2, attained an energy density value of 14.55 Wh/kg at a power density equal to 350 W/kg with an exceptional galvanostatic charge-discharge (GCD) cyclic stability equal to 91% following 10 000 cycles. Therefore, this review presents a novel functionalized graphene-based material incorporating hydroxyl and sulfonyl groups, which holds promise in future energy storage applications.

High accuracy graphene-based refractive index sensor: Analytical approach

A high-precision graphene-based refractive index (RI) sensor is suggested in this article. Because resonances represent a specific field distribution, optical sensors show a very high sensitivity to environment RI changes. These optical sensors' sensitivity is profoundly subordinate to the materials used in the sensor as well as the sensor structure. The structure of the proposed sensor consists of the following layers, respectively: gold layer, SiO2, graphene and the substance under test (analyte). The transmission line model (TLM) was also fully investigated for this absorber and the inductor and capacitor values related to the simulation were obtained. There was a suitable agreement between the simulation results and TLM. This sensor has nearly perfect absorption and the absorption peak of this sensor in the absorption curve is 99.99 % at 3.24 THz with an average quality factor of 11.39. This absorber-based sensor sensitivity to changing the test medium (analyte) RI is so high that with a very small change in the RI of the analyte, the absorption peak is shifted, and its frequency changes. This sensor sensitivity and figure of merit (FOM) to variation of the analyte RI 726 GHz/RIU 2.69 RIU-1 were acquired, respectively. The characteristics of this sensor can be adjusted by variating the bias voltage exerted on the graphene layer. The Computer Simulation Technology (CST) and Advanced Design System (ADS) software have been used to analyze this structure. This proposed sensor can be used as a good sensor in biomedical applications and early diagnosis of diseases such as leukemia and types of cancer and influenza.

Supercapacitors and triboelectric nanogenerators based on electrodes of greener iron nanoparticles/carbon nanotubes composites

The development of supporting materials based on carbon nanotubes (CNTs) impregnated with iron nanoparticles via a sustainable and green synthesis employing plant extract of Punica granatum L. leaves was carried out for the iron nanoparticle modification and the following impregnation into the carbon nanotubes composites (CNT-Fe) that were also coated with polypyrrole (CNT-Fe + PPy) for use as electrode for supercapacitor and triboelectric nanogenerators. The electrochemical characterization of the materials by cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD) assays revealed that the CNT-Fe + PPy gave rise to better performance due to the association of double-layer capacitance behavior of carbon derivative in association with the pseudocapacitance contribution of PPy resulting in an areal capacitance value 202 mF/ cm2 for the overall composite. In terms of the application of electrodes in triboelectric nanogenerators, the best performance for the composite of CNT-Fe + PPy was 60 V for output voltage and power density of 6 μW/cm2. The integrated system showed that the supercapacitors can be charged directly by the nanogenerator from 0 to 42 mV in 300 s. The successful green synthesis of iron nanoparticles on CNT and further PPy coating provides a feasible method for the design and synthesis of high-performance SCs and TENGs electrode materials. This work provides a systematic approach that moves the research front forward by generating data that underpins further research in self-powered electronic devices.

Quantum capacitance behavior of Ti2CO2/MoS2 heterostructures with 3d and 4d transition-metal doping

The storage capacity of capacity, quantum capacitance behavior, and atomic stability of O-defected, S-defected, 3d and 4d transition-metal (3d-TMs: Sc, Ti, V, Cr, Mn, Fe, Co, and Ni; 4d-TMs: Y, Zr, Nb, Mo, Ru, Rh, Pd, and Ag) doped Ti2CO2/MoS2 heterostructures were studied by density functional theory (DFT). Pristine Ti2CO2/MoS2 exhibited a high quantum capacitance of 1038.62 μF/cm2 at the positive potential. The appearance of O-vacancy in Ti2CO2-layer enhanced the capacitance of Ti2CO2/MoS2 at negative bias, and S-vacancy induced an obvious improvement of quantum capacitance at 0 V. After introducing various transition metals into modified Ti2CO2/MoS2 heterostructures, the doping in pristine structures increased the capacitance value to be 1182.71 μF/cm2 (Y-doping), while TM-doping in S-vacancy defected Ti2CO2/MoS2 systems induced a slight decrease of capacitance at positive potentials. For TM-doped O-defected Ti2CO2/MoS2, only Sc- and Y-doped systems exhibited higher quantum capacitance than the pristine Ti2CO2/MoS2, which were 1093.60 and 1096.26 μF/cm2. Due to the obvious advantage of capacitance of pristine Ti2CO2/MoS2 than Ti2CO2 or MoS2 single-layer at the positive bias, it can be used as effective anodes for high-capacitance supercapacitors, while 3d or 4d TM-doping had no significant enhancement in capacitance behaviors. The findings in this study were supposed to be theoretical data base to design high-performance supercapacitors.

Design and Characterization of Printed Flexible Humidity Sensor

The development of humidity sensors is essential for applications in the environmental, agriculture, medical and semiconductor industries. This research focused on using advanced printed board circuit (PCB) printing technology to fabricate a humidity moisture sensor. The fabrication of humidity sensor was done using two different polymers: p-HEMA and polyimide, and the performance was compared. Humidity sensors with p-HEMA showed higher capacitance value and more sensitivity than the humidity sensors with polyimide. The variation in sensitivity was higher between the relative humidity from 60% to 90% than between 45% to 60%.

ISOLATED PINEAPPLE PEEL MICROCELLULOSE AS A MATRIX FOR POLYPYRROLE-BASED CAPACITOR

This study investigates the viability of utilizing microcellulose extracted from pineapple peel waste as a sustainable and cost-effective matrix material for polypyrrole (PPy)-based capacitors. A novel PPy/microcellulose composite was synthesized with varying pyrrole volumes (1-2 mL) and characterized using Fourier Transform Infrared (FTIR) and X-ray diffraction (XRD) analyses. FTIR analysis confirmed successful cellulose isolation, while XRD indicated a similarity between the extracted pineapple peel and commercial cellulose. Capacitor cells were fabricated using the synthesized composites, and their capacitance performance was evaluated. Notably, cells containing 2 mL of PPy exhibited the highest capacitance values. Additionally, the source of cellulose had minimal influence on the resulting capacitance. This study suggests that microcellulose derived from pineapple peel waste holds promise as a sustainable alternative to traditional matrix materials for high-performance capacitors.

Fabrication of Activated Carbon Derived from Glycerin Pitch for Desulfurization of Model Fuel Oil and Electrode Application.

One of the world's challenging energy issues is introducing practical and affordable technology for organosulfur removal in fuel. Adsorptive desulfurization (ADS) can address this issue if highly effective activated carbon (AC) derived from industrial waste with excellent textural properties is used. In this study, the derived ACs from glycerin pitch loaded with P and Fe (AC/P and AC/Fe) were used as adsorbents for the ADS of model fuel oils, such as dibenzothiophene (DBT) at mild operating conditions. Under the optimized experimental conditions, 0.3 g of adsorbent dosage, 60 min reaction time, 30 °C temperature, and pH 4, the maximal DBT removal of 96.28 and 43.64%, respectively, for AC/P and AC/Fe was realized. The results indicated that the phosphorus-doped AC/P increases the selectivity of the ADS mechanism for DBT removal. Kinetic investigations disclosed that the adsorption process follows second-pseudo-order kinetics and the Langmuir adsorption isotherm model. The adsorbents remained active for five successive reuses, indicating their robust real-world applications. The electrochemical properties of the fabricated carbon electrodes were analyzed via cyclic voltammetry by coating the ACs with polytetrafluoroethylene (PTFE) as a binder. The transition-metal-doped AC/Fe, though exhibiting 5 times lower surface area, showed the highest specific capacitance at a scan rate of 5 mVs-1 (0.65 μF cm-2). Similarly, the extended AC:PTFE capacitor at a 10% binder ratio offered the maximum capacitance value (1.13 μF cm-2). The synthesized ACs demonstrated potential application as an electrode material, and hence glycerin pitch could be a low-cost precursor to improve the feasibility of commercial production of AC.

A Remarkable Pt Doped CNT Catalyst as a Double Functional Material: Its Application for Hydrogen Production and Supercapacitor

In this study, by producing bifunctional material, hydrolysis, and supercapacitor applications were investigated. The carbon nanotube-supported Pt catalyst was prepared using the sodium borohydride (NaBH<sub>4</sub>) reduction. Surface characterization of the synthesized Pt/CNT catalyst was performed using scanning electron microscopy-energy dıstrıbutıon X-ray spectrometer (SEM-EDX), X-ray diffraction (XRD), and transmission electron microscopy (TEM). Hydrolysis experiments were performed after deciding on the appropriate atomic ratio from the Pt/CNT catalysts synthesized in different nuclear ratios. The parameters affecting the hydrogen production from NaBH<sub>4</sub> were examined. As a result of the kinetic calculations, the initial rates of reaction for 30°C and 60°C were calculated as 21949,69 mlH<sub>2</sub>g<sub>cat</sub>min<sup>-1</sup> and 70018,18 mlH<sub>2</sub>g<sub>cat</sub>min<sup>-1</sup>. Galvastonic charge-discharge (GCD), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) were used as characterization techniques for the use of Pt/CNT catalysts as electrodes in supercapacitor applications. The specific capacitance value of 7% Pt/CNT catalyst at 1 A/g current density was calculated as 57,78 F/g. Energy and power density were calculated as 8,025 Wh/kg and 963 W/kg, respectively. Therefore, this catalyst is called a “cap-cat” with capacitor properties. The catalyst used in this study is promising for this recently studied topic.

Palladium enhanced electrochemical supercapacitive performance of chromium oxide thin films synthesized by sputtering process

Recently, the use of transition metal oxide electrodes for supercapacitor applications has increased due to the possibility of variable mixed valence states. The present study has established the use of Pd-Cr2O3 composite thin films as a working electrode for high-performance supercapacitors. The reactive dc magnetron co-sputtering method has been used for the fabrication of thin film of Cr2O3 and Pd-Cr2O3 on SS-304 substrate. X-ray diffraction and X-ray photoemission spectroscopy techniques were used to examine the surface chemistry and phase purity of chromium oxide and Pd-Cr2O3 composite thin films. The incorporation of Pd in Cr2O3 delivers a drastic change in the surface morphology. Due to the modified morphology and electronic properties, a noticeable improvement in the electrochemical properties of Pd-Cr2O3 electrode is observed. The obtained value of specific capacitance for this electrode is 401 Fg−1 at 0.1 mAcm−2 scan rate and within the potential window range 0 to +1.2 V. This value of specific capacitance is almost twice in comparison to the Cr2O3 based electrode. The Pd-Cr2O3 composite thin film shows a good cycle retention capability of 8000 cycles with 87.5 % retention. The obtained value of energy density and power density for Pd-Cr2O3 electrode was 80.2 Whkg−1 and 3.23 kWkg−1, respectively at 0.1 mAcm−2. Consequently, this composite material electrode can be seen as a promising advancement for electrodes in supercapacitor devices.

Transfiguring energy with an advantageous supercapacitor integrating MoS2/carbon quantum dots bi‐composites into a high‐performance polypyrrole matrix for unprecedented efficiency

AbstractFor the first time, a simple one‐step in situ chemical polymerization technique is used to create a novel molybdenum disulphide/sulphonated carbon quantum dots (CQDs) and polypyrrole (MCP) nanocomposite that is extended for successful use in charge storage supercapacitor (SC) device. By inheriting qualities of excellent electrical conductivity of MoS2, CQDs and improved pseudocapacitive activity of polypyrrole (PPy), the MCP nanocomposite provides a suitable SC electrode material. 0.6 MCP nanocomposited three‐electrode system demonstrates 93.21% retention after 5000 cycles, and a maximum specific capacity of 2253 F/g at 2 mV/s with higher side of energy density as 106.06 Wh/kg along with a considerable power density as 180.28 W/kg. Using MCP as anode and an AC or activated charcoal electrode as cathode, a solid‐state asymmetric supercapacitor (ASC) was constructed. The fabricated device supplies a greater value of specific capacitance as 154.09 F/g at 100 mV/s and 175 F/g at 0.1 A/g, also evidenced superior energy density data as 126 Wh/kg along with an appreciable power density of 604.8 W/kg. After charging the ASC for 2 min, the light emitting diode shone for 5 min. The findings underpin that MCP is a potential electrode material that could be utilized as a better alternative in futuristic supercapacitor devices.

Electrolytic performance of sodium alginate-poly vinyl alcohol matrix with ammonium bromide for proton conduction: Applications in electrochemical systems

Polymer blend electrolytes based on poly(vinyl alcohol) (PVA) and sodium alginate (NaAlg) were prepared using the solution casting method. These electrolytes were doped with varying amounts of ammonium bromide (NH4Br). The compatibility of NH4Br with PVA:NaAlg polymers was examined through X-ray diffraction (XRD) and Fourier-transform infrared (FTIR) studies. The FTIR assessment confirmed the formation of a complex between PVA:NaAlg and the added salt, as evidenced by modifications and reductions in the intensity of FTIR bands related to functional groups. The conductivity and dielectric behavior of the samples were analyzed using AC impedance spectroscopy. The sample with 20 wt% of added salt exhibited a higher ionic conductivity of 1.661×10−5 Scm−1. Activation energy and relaxation time were estimated, and dielectric studies revealed a non-Debye nature. The conduction mechanism was best described by the correlated overlapping large polaron tunneling model (OLPT). The highest conducting sample was found to be suitable for electrochemical devices, as demonstrated by transference number (TNM), cyclic volumetric (CV), and linear sweep voltammetry (LSV) analyses. This high-conductivity sample can be employed in electrochemical devices such as EDLC. The cyclic voltammetry (CV) curve exhibited a nearly rectangular shape with non-faradaic peaks. GCD(Galvanostatic charge-discharge) analysis yielded specific capacitance, power density, and energy density values of 125.01 Fg−1, 1037 WKg−1, and 14.06 WhKg−1 respectively. These results indicate that polymer electrolytes show great promise as electrolytes in proton-conducting electrochemical devices.

Characterization and antibacterial studies of Sn doped CuO nanocomposite using centratherum punctatum leaf extract

In order to synthesize CuO, SnO2, and Sn doped CuO nanocomposites, accessible and non-toxic materials, specifically leaf extract from Centratherum punctatum, were used in this work to apply the concepts and practices of green chemistry. These methods are both economical and environmentally friendly. A comprehensive range of characterisation techniques, including as FTIR, X-ray diffraction, and UV-vis spectroscopy, were also used to confirm the structures of all the produced nanomaterials. Instead, FESEM and EDAX were used to analyze the morphologies and elemental composition of recently produced nanomaterials. A decline in the optical band gap values was indicated by the red shift observed in the UV-vis study following tin doping. A sample's presence of different functional groups is confirmed by FT-IR analysis. For CuO NPs, SnO2, and Sn doped CuO NCs, the XRD results yielded crystallite sizes of 6 nm, 21 nm, and 29 nm, respectively, for the produced particles. The ferromagnetic, diamagnetic, and super paramagnetic characteristics of the produced samples at room temperature were validated by vibrating sample magnetometer experiments. Cyclic voltammetry is used to examine the nanoparticles' electrochemical analysis. Using Sn doped CuO nanocomposite material, it shows a high specific capacitance value of about ~187 Fg-1 at a current density of 10 mV/s. It was found from the electrochemical studies that the produced nanomaterials are suitable for capacitive behaviour. After all, the presence of inhibition zones surrounding each well led us to the conclusion that the nanoparticles exhibited antibacterial activity against the pathogenic strains of Staphylococcus aureus and Escherichia coli.

Enhancing the energy storage performance of titanium dioxide electrode material by green doping of Nd2O3 nanoparticles for electrochemical supercapacitors

Doping of sesquioxide alloy onto TiO2 nanomaterials was carried out in a novel green chemistry method using Corallo carpus epigaeus to fabricate the electrodes for pseudocapacitors. The conducted X-ray diffraction studies demonstrated the tetragonal phase of TiO2 and hexagonal phase of Nd2O3 nanomaterials. Morphological analysis revealed the irregular shape of TiO2 materials, each exceeding 100 nm in size, while Nd2O3 materials exhibited a spherical shape within the range of 10–20 nm. Electrochemical investigations unveiled a quasi-rectangular shape in cyclic voltammetric studies and a triangular shape in galvanostatic reactions, suggesting superior electrochemical performance of the electrodes. The doped electrodes exhibited a higher specific capacitance value (785.71 F/g) compared to pure TiO2 (707.14 F/g) at a current density of 1 A/g. These findings affirm the suitability of doped electrode materials for applications in electrical energy storage.

Biomass waste derived from cassia fistula into value-added porous carbon electrode for aqueous symmetric supercapacitors

Activated carbon derived from biomass sources has been renowned as one of the key materials and economical precursors for numerous energy conversion and storage applications. Herein, we utilized a less explored Cassia fistula (Pulp and seed) biomass as the carbon source for supercapacitor application. Further, a less toxic and low activation method has been implemented to activate the biomass-derived carbon. The highly dense seed resulted in better porous compared to the pulp source. The electrochemical performances of the bio-carbon electrodes have been examined by CV, GCD, and EIS studies. The activated carbon derived from the Cassia fistula seed (CFSA) electrode achieved a specific capacitance value of 136.5 Fg−1 at 0.5 Ag−1 in 3 M KOH. Moreover, the electrode demonstrates an extremely long stability by sustaining 98 % of initial capacitance after 10,000 cycles, which signifies the robust electrochemical stability behavior of the obtained electrode. Further, the aqueous symmetric supercapacitor achieved a maximum energy and power density of 7.2 WhKg−1 and 3488.1 WKg−1, respectively. Likewise, after 10,000 stability cycles, the cell retains 96.4 % capacitance at 5 Ag−1 which denotes the noteworthy capacitive behaviour of the CFSA electrode. Thus, the present work suggests an eco-friendly resource for developing an effectual carbon electrode for energy storage applications.