Power Density Values Research Articles

Graphene-Based Nanostructured Cathodes for Polymer Electrolyte Membrane Fuel Cells with Increased Resource

Pt on carbon black (Pt/C) has been widely used as a catalyst for both ORR and hydrogen oxidation reaction (HOR), but its stability is compromised due to carbon corrosion and catalyst poisoning, leading to low Pt utilization. To address this issue, this study suggests replacing carbon black with graphene in the catalyst layer. The importance of this work lies in the detailed examination of novel electrocatalysts with high electrocatalytic activity for large-scale power generation. In this paper, we discuss the use of regulatory techniques like structure tuning and composition optimization to construct nanocatalysts impregnated with noble and non-noble metals on graphene supports. Finally, it highlights the limitations and advantages of these nanocatalysts along with some future perspectives. Our objective is that this summary will help in the research and rational design of graphene-based nanostructures for efficient ORR electrocatalysis. The results of this study showed that the performances of graphene-based catalysts show high electrochemical active surface areas for Pt-Fe/GNPs and Pt-Ni/GNPs catalysts (132 and 136 m2 g−1, respectively) at 100 operating cycles. Also, high current densities and power densities were observed for Pt3-Ni/G and Pt-Co/G catalysts used at the cathode. The values for current density were 1.590 and 1.779 A cm−2, respectively, while the corresponding values for power density were 0.57 and 0.785 W cm−2.

Effect of Reduced Graphene Oxide on Optimized Pencil Graphite Electrodes in Enzymatic Glucose Biofuel Cell

Pencil Graphite Electrodes (PGE) have been used recently over carbon-based electrodes in the application of Enzymatic Glucose Biofuel Cell (EGBC). Cost and time effective bioelectrodes were prepared by using PGEs from the broad range of graphite (carbon) containing pencils like 12B, B, 5H and H from Apsara make and HB and B PGEs from Camlin make using single step deposition of Reduced Graphene Oxide (rGO) in 5M HNO3 as an electrolyte by Cyclic Voltammetry (CV) in the range of -1.0 to +1.9V w.r.t Ag/AgCl with the scan rate of 50mV/s. Optimized HB and B PGEs were used to develop two sets of bioelectrodes to know the applicability in EGFC. In the first set HB-PGE/MWCNT-COOH/laccase as biocathode and B-PGE/ MWCNT-COOH/GOx as bioanode and in the second set HB-PGE/rGO/MWCNT-COOH/laccase as biocathode and B-PGE/rGO/MWCNT-COOH/GOx as bioanode respectively. Studies revealed that the full cell performance of first set shown 95 maximum current density at 0.22V w.r.t Ag/AgCl and for the second set 1.7 at maximum current density at 0.4V w.r.t Ag/AgCl in 5mM glucose solution with 1mM p-benzoquinone as the anodic mediator in both cases. The effect of rGO on PGE/MWCNT-COOH/GOx increased the OCV, power density and current density (1.7 mA/ ) values 1689% higher than to the PGEs without the deposition of rGO.

The influence of ZIF-L in a microbial fuel cell (MFC) cathode for oxygen reduction reaction (ORR).

Microbial fuel cells (MFCs) utilize the metabolic activities of microorganisms, through which the chemical energy is directly converted into electrical energy. Bacteria produce electrons by means of oxidation of organic/inorganic substrates within the MFCs. Metal organic frameworks (MOFs) that are porous coordination polymers have gained much interest in the field of efficient catalysts due to their unique characteristics. The utilization of MOF catalysts for oxygen reduction reaction (ORR) in the MFC cathode is one of the most remarkable research areas in material science. MOF (zeolitic imidazole framework-leaf like, ZIF-L) decorated cathode system was employed for the first time in MFC to monitor the improvement in performance by taking advantages of both electrocatalytic activity and porosity of MOFs for the utilization of bioelectrons for ORR. Analysis of ORR performance of ZIF-L/carbon black (CB) composite cathode demonstrated that ZIF-L containing cathode system had an improved ORR activity compared to MFC cathode materials in the literature. The remarkable current density value of 2.1mAcm-2 and the maximum power density value of 1,462 mW m-2 at room temperature revealed that ZIF-L decorated cathode is an excellent alternative for efficient reduction of oxygen in MFCs.

Electrifying energy storage by investigating the electrochemical behavior of CoCr2O4/graphene-oxide nanocomposite as supercapacitor high performance electrode material

This study reports novel three-step electrochemical fabrication of CoCr2O4/graphene-oxide nanocomposite on glassy carbon electrode including sequential synthesis of graphene-oxide using modified Hummer's method, CoCr2O4 nanoparticles using sol-gel method and the cost-effective co-precipitation technique for nanocomposite formation. The resulting nanocomposite was subjected to comprehensive analytical and morphological analysis. X-ray diffractometry (XRD) confirms nanocomposite formation with reduced average crystallite size value of 26.9 nm whereas SEM indicates spherical grains existence within nanocomposite. Energy-dispersive X-ray spectrometry (EDS) confirms no impurity peak existence whereas Raman spectroscopy clearly indicated D and G band existence at 1345 and 1587 cm−1 respectively. Photoluminescent spectra reveals decreasing trend in band gap value about 3.49 eV. The electrochemical properties of CoCr2O4/graphene-oxide nanocomposite electrode explored, showcasing remarkable capacitance with a surface area of merely 0.068 cm2, 574.8 F/g specific capacitance in alkaline 1M KOH and 488.6 F/g specific capacitance in acidic 0.1M H2SO4 electrolyte. Moreover, synthesized nanocomposite demonstrates remarkable electrochemical stability resulting capacitance retention about 95 % after 100 cycles in 1M KOH electrolyte. GCD analysis reveals impressive power and energy density values of 2489 W/kg and 14.88 Wh/kg respectively. These outstanding properties make the nanocomposite an attractive material for next-generation supercapacitors and energy storage solutions.

Efficient hybrid supercapacitor performance enabled by large surface area of 2D mesoporous zinc sulfide nano-sheets synthesized via microwaves

Researchers have shown a significant amount of interest in synthesizing high energy density supercapacitors using a simplest, fast, and low cost technique. The electrochemical performance of supercapacitors can be impacted by the surface area and morphology of electrode materials. A one-step, rapid, and economical microwave-assisted synthesis technique was employed in this study in order to prepare mesoporous nanosheets that are composed of zinc sulfide. The ZnS-based nanosheets possess a large surface area of ∼120 m2g−1 and a mesoporous structure of a pore diameter of <22 nm, which offers numerous electrochemical active sites and it facilitates an excellent super capacitive performance, which is due to its shortened ion/electron diffusion path. The prepared mesoporous nanosheets exhibit a higher specific capacitance of 2282 Fg−1 (1037 C/g) when subjected to a 1 Ag−1 in 2 M KOH aqueous electrolyte with high capability rate. The fabricated device exhibits a high specific capacitance of 252.5 Fg−1 (140 C/g) at 1 Ag−1, which produces a remarkable energy density of about 90 Whkg−1 at 800 Wkg−1 value of power density and an excellent retention of ∼95 % after 10,000 cycles at 6 Ag−1. This study designed an instant, straightforward and low-cost approach to fabricate ZnS nanosheet electrode materials that exhibit excellent performance for supercapacitor applications.

INNV-26. FEASIBILITY EVALUATION OF TUMOR TREATING FIELDS (TTFIELDS) THERAPY FOR BRAINSTEM GLIOMAS

Abstract BACKGROUND Tumor Treating Fields (TTFields) therapy is a novel anti-mitotic therapy that is FDA-approved for use in patients with newly diagnosed and recurrent glioblastoma (GBM). However, TTFields therapy is currently only approved for supratentorial GBM, and the feasibility of TTFields therapy for treating infratentorial GBM remains unknown. TTFields values of average local minimum power density (LMiPD) &amp;gt;1.15 mW/cm3 and local minimum field intensity (LMiFI) &amp;gt;1.06 V/cm, were associated with improved OS and PFS based on a posthoc analysis of the EF-14 study. This is a dosimetric planning evaluation of the feasibility of TTFields therapy for brainstem gliomas. METHODS MRIs of patients with brainstem gliomas were used for this dosimetric evaluation, with planning conducted using MAXPOINT (Novocure, Switzerland). Gross tumor volume (GTV) for TTFields planning was defined as enhancing tumor on T1 post contrast MRI. Clinical target volume (CTV) was defined as GTV expanded by a 3 mm margin around sum total of resection cavity, necrotic core, and enhancing tumor. LMiPD and LMiFI to the GTV and CTV were evaluated. RESULTS A total of 5 patients with brainstem gliomas were included in this study. The median GTV volume was 8.2 cc (range: 3.8 – 13.5 cc), and median CTV volume was 18.6 cc (range: 9.1 – 23.4 cc). The median LMiPD for GTV and CTV were 1.9 (range: 1.1 – 2) and 1.9 (range: 1-2.1) mW/cm3, respectively. The median LMiFI for GTV and CTV were 1.3 (range: 1.1-1.6) and 1.2 (range: 1.1-1.6) V/cm, respectively. CONCLUSION LMiPD and LMiFI values for brainstem gliomas achieved levels that are consistent with those associated with improved OS and PFS in posthoc analyses in supratentorial GBM. This dosimetric planning study suggests feasibility and theoretical benefit of TTFields for brainstem gliomas. Further clinical evaluation is warranted to validate its efficacy.

Kinetic study on the degradation of Acid Red 88 azo dye in a constructed wetland-microbial fuel cell inoculated with Shewanella oneidensis MR-1.

Removal of Acid Red 88 (AR88) as an azo dye from the synthetic type of wastewater was studied in a laboratory-made constructed wetland microbial fuel cell (CW-MFC) inoculated with Shewanella oneidensis MR-1 (SOMR-1). Plant cultivation was implemented using a typical CW plant known as Cyperus alternifolius. The complexity of the SOMR-1 cell membrane having different carriers of electrons and H+ ions gives the microbe special enzymatic ability to participate in the AR88 oxidation link to the O2 reduction. Nernst equation developed based on analyzing the involved redox potential values in these electron exchanges is describable quantitatively in terms of the spontaneity of the catalyzed reaction. Power density (PD) at 100mg/L of the AR88 under closed-circuit conditions in the presence of the plant was 11.83 mW/m2. Reduction of internal resistance positively affected the PD value. In determining degradation kinetics, two approaches were undertaken: chemically in terms of first- and second-order reactions and biochemically in terms of the mathematical equations for rate determination developed on the basis of substrate inhibitory concept. The first-order rate constant was 0.263h-1 without plant cultivation and 0.324h-1 with plant cultivation. The Haldane kinetic model revealed low ks and ki values indicating effective degradation of the AR88. Moreover, the importance of acclimatization in terms of the crucial role of lactate was discussed. These findings suggest that integrating the SOMR-1 electrochemical role with CW-MFC could be a promising approach for the efficient degradation of azo dyes in wastewater treatment.

Electrochemical properties of Zn and Al-doped SnSb for asymmetric supercapacitor application

Supercapacitors or electrochemical capacitors are known for their supporting pulse power because of their high-power density compared to the battery. In this work, Al and Zn doped SnSb, i.e., Sn0.95SbZn0.05, Sn0.9SbZn0.1, Sn0.95SbAl0.05, and Sn0.9SbAl0.1 have been synthesized through chemical co-precipitation method. The powder X-ray diffraction, Raman spectroscopy, and UV–visible spectroscopy are intensely scrutinised to infer the phase formation, vibrational, and optical properties of the synthesized materials. Furthermore, the SEM, TEM, and X-ray photoelectron spectroscopy are used to study the material's morphology, chemical, and oxidation state; the Zn-doped SnSb alone focused because of their better electrochemical performance than the Al-doped SnSb. Using a three-electrode setup, the electrochemical performance of the following Sn0.95SbZn0.05, Sn0.9SbZn0.1, Sn0.95SbAl0.05, and Sn0.9SbAl0.1 are evaluated in that Sn0.95SbZn0.05 has recorded higher specific capacitance of 588 F/g at 1A/g than the other. Then, the electrochemical analysis is further proceeded with the fabrication of an asymmetric device based on Swagelok assembly in which activated carbon acts as the negative electrode and Sn0.95SbZn0.05 as the positive electrode and has recorded the maximum power and energy density value of 4266 W/Kg and energy density of 8.57 Wh/Kg. It also has shown outstanding cyclic stability for 5000 charge-discharge cycles at 10 A/g.

Morphological impact on the supercapacitive performance of nanostructured ZnO electrodes

This study investigated the influence of the ZnO morphology on the energy storage capacity of symmetric supercapacitor devices, focusing on the defect centers present in the materials due to morpho-structural differences. Thus, ZnOs with five different morphologies were synthesized with varying methods in which the nanoparticles have the form of flowers, bullets, pyramids, hexagons, and rods. All materials were thoroughly characterized by scanning/transmission electron microscopy, X-ray diffraction, and spectroscopic techniques like photoluminescence, UV–Vis, Raman, and electron paramagnetic resonance spectroscopy. Subsequently, the ZnO-based materials were assembled in symmetric supercapacitor devices to test their energy storage capabilities. The ZnO with nanorod and hexagonal morphologies showed the best specific capacity (180 and 142 F/g), energy density (25 and 19 Wh/kg), and power density (211 and 252 kW/kg) values. The importance of the defect centers in the materials was highlighted, where the ratio between the Zn and O vacancies, evidenced by EPR spectroscopy, plays a crucial role in the ZnO materials’ energy storage capacity. The Raman results support the proposed model, which underlines the importance of oxygen vacancies. In contrast, BET measurements show that the specific surface area of the morphologically distinct ZnO materials does not change drastically, validating the importance of the defect centers in the materials. A so-called “bottle-neck” effect is proposed to describe the relation between the paramagnetic vacancies and the electric properties of the materials.

Sustainable pseudocapacitance potential of a hybrid triad involving activated carbon derived from polyester wastes

This study introduces an innovative approach to fabricate high-efficiency supercapacitor electrodes by utilizing waste polyester (PES), a common fabric waste, as a precursor for producing activated carbon. This approach not only addresses waste disposal issues but also provides a valuable resource for various environmental and industrial applications. Through a series of chemical and thermal treatments, PES waste is transformed into a porous carbon structure, which is then functionalized with PPy and V2O5 to enhance its electrical conductivity and electrochemical performance. The synthesized composite is characterized by several analytical and spectral techniques to elucidate the morphological, structural and surface properties. The specific surface area of the hybrid composite material is 50.4 m2g−1. Cyclic voltammetry, galvanostatic charge-discharge and impedance spectroscopy are employed to evaluate the performance of the composites as supercapacitor electrodes. From the CV curves, the electrochemically active surface area was calculated to be 0.085 m2g-1. The composite exhibits a remarkable specific capacitance of 535 Fg-1 and energy as well as power density values of 171 W h Kg−1 and 2877 W Kg−1 respectively at a current density of 2 Ag−1. The material was fabricated into device and was observed to show excellent cycling satbility for up to 10,000 cycles.

Ignition of anthracite microparticles by continuous laser radiation with wavelengths of 450 and 808 nm

The energy and spectral-kinetic characteristics of ignition of anthracite microparticle powders with a bulk density of 0.5 g/cm3 were measured when exposed to continuous laser radiation at wavelengths λ = 450 and 808 nm with an exposure time of 1 second. Ignition delay times were measured depending on the radiation power density and critical values of the ignition energy density of anthracite samples were determined. The energy cost of igniting anthracite for radiation with λ = 450 nm is less than for radiation with λ = 808 nm. In the emission spectra of anthracite resulting from the absorption of laser radiation, there is a glow associated with the release and ignition of volatile substances (flame CO, glow of excited molecules CO, C2 and H2O) and thermal glow associated mainly with the heated surface of the samples, as well as the flight of incandescent carbon particles.

Wind power plant site selection problem solution using GIS and resource assessment and analysis of wind energy potential by estimating Weibull distribution function for sustainable energy production: The case of Bitlis/Turkey

Wind energy, being a sustainable energy source, is a benign, dependable, limitless, and cost-effective source of energy. This study involved the creation of a wind power plant site selection map at a provincial scale using a GIS application. The map took into account both environmental risks and environmental criteria. A wind energy measurement station of the PCE-FWS 20 type, equipped with a touch screen, was installed in the Rahva campus of Bitlis Eren University. Over the course of one year, data on wind direction, wind speed, temperature, relative humidity, and air pressure were collected at 5-s intervals and averaged over 20-min periods. The purpose of this study was to assess the suitability of the measured region for wind energy potential. A comprehensive statistical analysis was conducted using all the data collected during this period to assess the wind energy potential in the studied region. The Weibull distribution was employed to analyse the wind energy potential of this particular region. We employed graphical techniques to ascertain the Weibull distribution. The wind data analysis and simulation were conducted using the Matlab application. Analysed were the monthly statistical wind energy potential of the region, wherein the average wind speed and power density values were determined and presented through graphs at 20-min intervals. Upon analyzing the map generated using the Geographical Information Systems (GIS) technique, it has been ascertained that Bitlis Eren University Rahva campus is located in favorable areas.

Supercapacitor devices based on multiphase MgTiO3 perovskites doped with Mn2+ ions

Recently, perovskites have become a hotspot for researchers attempting to exploit metal and oxygen vacancies in structures of the form MTiO3, facilitating the convenient electron/hole migration, thus displaying interesting properties. Magnesium Titanate (MgTiO3) is a prominent part of the perovskite class, exhibiting remarkable electrical, thermal, and chemical properties. Undoped and Mn-doped MgTiO3 samples were obtained using a solid-state reaction starting from previously synthesized MgO and TiO2 powders, which were separately doped with different Mn ion concentrations. The resulting multiphase materials with a major MgTiO3 phase were thoroughly morpho-structurally analyzed employing XRD, STEM, Raman, PL, XPS, and EPR spectroscopy. The electrochemical results indicate that they show superior performance when used as electrode materials for supercapacitor application due to the high defect concentration as shown in EPR and PL spectroscopy and the ferroelectric behavior observed in XPS and XRD. When used in symmetric and asymmetric supercapacitor devices, they show promising results, with specific capacity values reaching up to 109 F/g for the symmetric and 609 F/g for the asymmetric devices, while energy and power density values reached 84.7 Wh/kg and 90.8 kW/kg respectively, proving a great potential in the energy storage field.

Supercapacitor and Photocatalytic Applications of Hydrothermally Synthesized of Polydymite Nanoparticles

The hydrothermal technique for producing polydymite nanoparticles (Ni3S4 NPs) for photocatalytic and supercapacitor utilization is the main emphasis in present work. The microstructural and electrochemical characterizations were conducted to determine the performance parameters of supercapacitor such as specific capacitance, efficiency, energy density and power density values using cyclic voltammetric (CV) and electrochemical impedance spectroscopic (EIS) techniques. The electrochemical characteristics of Ni3S4 NPs were studied using a TMS electrode in a 2 M KOH solution. This showed a specific capacitance value of 524 F g–1 at a current density of 1 A g–1. The Ni3S4 NPs showed good photocatalytic activities for the photodegradation of fast blue dye, the Ni3S4 NPs exhibits a 75.6% colour loss rate following the exposure for 120 min to UV radiation.

Fabrication of cerium vanadate-embedded on carbon based graphene material (rGO) with significant performance for supercapacitor electrode

This work examined the electrochemical properties of CeVO3 nanocomposite that were enhanced with reduced graphene oxide (rGO) and CeVO3 nanoparticles. The CeVO3/rGO fabricated using a typical hydrothermal process that was further characterized via XRD revealed the monoclinic crystalline structure of the CeVO3 nanoparticles. The presence of uniformly distributed particles structured CeVO3 and layer-structured (rGO) reduced graphene oxide in the nanocomposite materials was determined using scanning electron microscopy pictures. We evaluated the electro-chemical efficiency of the nanocrystals for enhanced working electrodes and supercapacitors with cerium vanadate (CeVO3) nanoparticles and the cerium vanadate (CeVO3) embedded on reduced graphene oxide (rGO). The analysis was conducted on 2.0 M aqueous KOH (potassium hydroxide) electrolytic solution and it achieved the capacitance of 355.46 F g−1 (10 mVs−1) was concluded by cyclic voltammetry analysis of the working electrode modified with pure CeVO3 nanomaterial. The addition of rGO improved the value of Cs to 947.30 F g−1 at the same scan speed (10 mVs−1). The CeVO3 nanoparticles and CeVO3/rGO nanocomposite exhibited the capacitance values of 698.54 F g−1 and 1403.35 F g−1 at 1 A g−1 respectively, as determined by GCD analysis. The fabricated with CeVO3 nanoparticles exhibited power density values of 254.1 W kg−1 and energy values of 25.05 W h kg−1. On the other hand, the CeVO3/rGO nanocomposite showed greater energy (Ed) and power (Pd) density of 54.72 W h kg−1 and 264.95 W kg−1, individually. After undergoing 5000th cycles, the material utilizing CeVO3/rGO composite maintained its stability. The electrochemical examination of the synthesized cerium vanadate nanoparticles revealed that the inclusion of rGO resulted in a hybrid capacitive nature and the proposed nanocomposite can be employed as supercapacitors or as electrodes in batteries as well as energy storage and generating device for future use.

Synthesis and performance of PdAu/ITO electrocatalysts in urea oxidation reaction

PdAu electrocatalysts were prepared in different atomic compositions supported on ITO by sodium Borohydride process. XRD results show intense crystalline peaks related to ITO, which may mask the appearance of less crystalline Pd or Au phases. Transmission results indicate agglomeration of palladium and gold nanoparticles on the support, a phenomenon compatible with metal oxide supports. Cyclic voltammograms in the absence of urea display characteristics commonly observed for PdAu electrodes, with an increase in oxygenated species compared to pure Pd or Au. Voltammograms in the presence of urea showed oxidation processes and lower current values, indicating catalyst deactivation processes. PdAu 75:25 demonstrated higher power density values compared to other prepared electrocatalysts, suggesting a synergy between Pd and Au for urea oxidation reaction.

α-Bi2O3 tubular rods coated on Bi2O2CO3 nanosheets for high-performance asymmetric supercapacitor applications

Mixed phases of bismuth oxide nanostructures as an active electrode material in supercapacitor applications have recently gained huge research interest. In this study, the layered Bi2O2CO3 nanosheets and the secondary phase of α-Bi2O3 tubular rods named Bi2O2CO3/α-Bi2O3 heterostructure have been synthesized and utilized for supercapacitor applications. The crystal nature and microstructure of the Bi2O2CO3/α-Bi2O3 heterostructure were initially confirmed by powder X-ray diffraction (p-XRD), Raman, UV-Vis diffuse reflectance spectroscopy (UV-DRS, absorbance), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) studies. X-ray photoelectron spectroscopy (XPS) measurements have investigated the oxidation states and chemical binding energies. Regarding the electrochemical performances, the Bi2O2CO3/α-Bi2O3 heterostructure as electro-active material delivered a maximum specific capacitance (Cs) value of 635 F g−1 at the given current density value of 1 A g−1 in a conventional three-electrode mode. A coin cell type electrode has been fabricated using Bi2O2CO3/α-Bi2O3 heterostructure, resulting in an asymmetric supercapacitor device cell (ASC), which has a Cs of 112 F g− 1 (at 1 A g− 1) and a power density and energy density values of 515 W kg−1 and 22.5 Wh kg−1 respectively. The two supercapacitor electrodes in sequence effectively ignite the red-light-emitting diode (LED). Moreover, in the ASC type Bi2O2CO3 /α-Bi2O3 heterostructure, the specific capacitance value was slightly reduced to 12.3 % by 2000 cycles, showing favourable cyclic performance and stability during the electrochemical process. Based on the above-mentioned characterization, the appropriate electrochemical performances of Bi2O2CO3/α-Bi2O3 tubular rod heterostructures make them a promising candidate for future energy storage devices.

Enhanced energy storage performance of Bi(Mg0.5Hf0.5)O3 modified K0.5Na0.5NbO3 relaxor ferroelectric ceramics via synergistic strategy

K0.5Na0.5NbO3 (KNN)-based ceramics with large polarization (Pmax) and submicron grain size are considered as promising candidates for dielectric capacitors. However, the existence of significant remnant polarization (Pr) imposes constraints on achieving high recoverable energy storage density (Wrec) and efficiency (η). In this study, we developed and produced ceramic materials by utilizing the composition of (1-x)K0.5Na0.5NbO3-xBi(Mg0.5Hf0.5)O3 ((1-x)KNN-xBMH, x = 0–0.22), employing a viscous polymer rolling technique. We utilized a combined strategy to improve the energy storage capabilities of these materials by manipulating their crystal structures, inducing relaxor behavior, and minimizing microdefects. As a result, we obtained an optimum Wrec of 3.32 J/cm3 and η of 85.37 % at an electric field strength of 350 kV/cm in the x = 0.18 ceramic. Furthermore, excellent temperature stability was observed within the temperature range 20–120 °C, along with frequency stability across frequencies between 5 and 500 Hz. Moreover, at 200 kV/cm in the same composition (i.e., 0.82KNN-0.18BMH), we obtained a power density value as high as 103.13 MW/cm3, accompanied by a fast discharge speed reaching 30.6 ns. Overall, our results demonstrate that the comprehensive energy storage performances exhibited by the 0.82KNN-0.18BMH ceramic make it highly promising for applications in pulsed-power supply.

Electrochemical properties of binder-free micro-blocks/sheets-based cadmium‑nickel-sulfide electrode materials for portable energy storage applications

The major goal of community is to synthesis the novel electrode materials for new energy storage sources to reduce the environmental pollution and to overcome the energy crises in developing countries. Herein, the authors synthesized a binder-free micro-blocks/sheets-based nickel sulfide, cadmium-sulfide‑nickel-sulfide (Ni-S, Cd-S-Ni-S) electrode materials (EMs) on nickel foam by home-made chemical vapor deposition technique. The XRD patterns reveals the development of polycrystalline Ni-S, Cd-S-Ni-S phases. The average crystallite size of Ni-S and Cd-Ni-S EMs are found to be ⁓32 to ⁓45 nm respectively. The microstructure of Ni-S is changed from cluster-of-nanoparticles/micro-blocks to nanosheets when a layer of Cd-S is condensed on Ni-S EMs. The EDX analysis confirms the presence of various wt% of Ni, Cd and S in Ni-S, Cd-S-Ni-S EMs. The molar ratios of Ni and S are found to be 1.46 and 0.46 in the synthesized Ni-S EMs. The molar ratios of Ni, Cd and S are found to be 0.459, 0.439 and 0.702 in the synthesized Cd-S-Ni-S EMs. The maximum values of specific capacitance, energy density and power density of Ni-S and Cd-S-Ni-S EMs are found to be 3305, 4086 F/g at 1 mV/s 25 Wh/kg and 1399 W/kg respectively. The capacitive contribution of Cd-S-Ni-S EMs is higher than Ni-S EMs, however, it is increased with increasing scan rates. The excellent capacity retention (75–92 %), good cyclic stability, impedance analysis show that the synthesized Ni-S, Cd-S-Ni-S EMs are suitable for energy storage devices like supercapacitor and batteries.

Boosting supercapacitor performance synergistically with Bi2O3/MnO2:rGO nanocomposites and redox additive electrolyte

The contemporary surge in energy demand underscores the imperative for improvements in energy conversion and storage technologies. In response, supercapacitor devices were engineered using nanocomposites (NCs) of Bi2O3/MnO2:rGO (BMR), and their electrochemical performance was systematically documented. The BMR NCs were hydrothermally prepared and their physicochemical characteristics were analyzed. The working electrode was constructed employing BMR NCs, and tested in a three-electrode setup to explore its electrochemical properties using the aqueous electrolytes consisted of 1 M KOH and 0.1 M K4[Fe(CN)6] added 1 M KOH (referred as Redox additive electrolyte - RAE). BMR NCs loaded working electrode exhibited 1441.1 Fg−1 of specific capacitance at 5 mVs−1 in RAE. Subsequently, asymmetrical supercapacitor devices were assembled, incorporating a cathode comprised of BMR NCs modified Ni foam and rGO-loaded Ni foam as an anode. The supercapacitor performances were evaluated using KOH and RAE in a two-electrode setup. The BMR NCs loaded supercapacitors demonstrated 9.42 Whkg−1 and 2100 Wkg−1, of energy and power densities, respectively, in KOH. Obtained energy and power density values were improved to 16.08 Whkg−1 and 2800 Wkg−1, respectively, by the utilization of RAE. Since the synthesized BMR NCs exhibited superior performances in RAE, the suggested combination of BMR NCs and RAE emerged as a more promising option for energy storage applications in real-time.