Novel chemical route for CeO2/MWCNTs composite towards highly bendable solid-state supercapacitor device

Electrode materials having high capacitance with outstanding stability are the critical issues for the development of flexible supercapacitors (SCs), which have recently received increasing attention. To meet these demands, coating of CeO2 nanoparticles have been performed onto MWCNTs by using facile chemical bath deposition (CBD) method. The formed CeO2/MWCNTs nanocomposite exhibits excellent electrochemical specific capacitance of 1215.7 F/g with 92.3% remarkable cyclic stability at 10000 cycles. Light-weight flexible symmetric solid-state supercapacitor (FSSC) device have been engineered by sandwiching PVA-LiClO4 gel between two CeO2/MWCNTs electrodes which exhibit an excellent supercapacitive performance owing to the integration of pseudocapacitive CeO2 nanoparticles onto electrochemical double layer capacitance (EDLC) behaved MWCNTs complex web-like structure. Remarkable specific capacitance of 486.5 F/g with much higher energy density of 85.7 Wh/kg shows the inherent potential of the fabricated device. Moreover, the low internal resistance adds exceptional stability along with unperturbed behavior even under high mechanical stress which can explore its applicability towards high-performance flexible supercapacitor for advanced portable electronic devices

Vanadium oxide anchored MWCNTs nanostructure for superior symmetric electrochemical supercapacitors

Proper selection of electrode material with sensible scheme is definitely significant to dodge commercial obstacles of supercapacitors. This challenge has been addressed by engineering prototype symmetric supercapacitor (SSC) device fabricated with enhanced supercapacitive vanadium (V) oxide integrated multi-walled carbon nanotubes (MWCNTs) composite as electrode material with Li-ion associating LiClO4 electrolyte. The V2O5/MWCNTs composite with nanoscale architecture has been synthesized with inexpensive and simple chemical bath deposition (CBD) method. The cyclic voltammetry of SSC device has exhibited the involvement of electrochemically active reversible redox process in the composite. The specific capacitance of 569.7 F/g at scan rate of 2 mV/s including excellent electrochemical stability of 89.2% at 4000 CV cycles have been achieved with operating potential window of 2 V. Furthermore, the device exhibits excellent energy density of 62 Wh/kg and exceptional power density of 11.5 kW/kg. The low resistive factors have driven the device towards the potential application as glowing of red LED for 10 s

Fractal-like kinetics for adsorption of Pb (II) on graphene oxide/hydrous zirconium oxide/crosslinked starch bio-composite: Application of Taguchi approach for optimization

This study deals with the decontamination of Pb (II) from aqueous environment using graphene oxide/hydrous zirconium oxide/crosslinked starch bio-composite (GZS-BC). Various instrumental techniques were used to characterize the GZS-BC. The main factors of Pb (II) sorption were optimized by Taguchi method. Under optimum conditions, (adsorbent dose: 40 mg, contact time: 180 min and initial Pb (II) concentration: 50 mg/L) maximum removal efficiency (98.50%) was achieved at pH 6. Various isotherm models were tested to fit the adsorption data and Freundlich isotherm model was the best fit model with high R2 values (0.9977–0.9983) and low values of χ2 (0.01–0.02) and APE (0.90–1.14). The kinetic data were investigated using classical and fractal-like kinetic equations. The fractal-like mixed 1,2-order kinetic model was the best fit model which pointed towards heterogeneous surface of GZS-BC with more than one type of sorption sites. Thermodynamic study shows that Pb (II) sorption onto GZS-BC was spontaneous and endothermic in nature. The values of ΔG° indicated that physisorption together with chemisorption was responsible for uptake of Pb (II).The authors are highly thankful to Department of Chemistry, AMU assisted through UGC DRS-SAP, DST-PURSE and DST-FIST programs for providing necessary facilities. The authors extend their sincere appreciation to the Researchers Supporting Project Number (RSP2023R266) King Saud University, Riyadh, Saudi Arabia for the support.Publicad

V2O5 encapsulated MWCNTs in 2D surface architecture : complete solid-state bendable highly stabilized energy efficient supercapacitor device

A simple and scalable approach has been reported for O encapsulation over interconnected multi-walled carbon nanotubes (MWCNTs) network using chemical bath deposition method. Chemically synthesized O/MWCNTs electrode exhibited excellent charge-discharge capability with extraordinary cycling retention of 93% over 4000 cycles in liquid-electrolyte. Electrochemical investigations have been performed to evaluate the origin of capacitive behavior from dual contribution of surface-controlled and diffusion-controlled charge components. Furthermore, a complete flexible solid-state, flexible symmetric supercapacitor (FSS-SSC) device was assembled with O/MWCNTs electrodes which yield remarkable values of specific power and energy densities along with enhanced cyclic stability over liquid configuration. As a practical demonstration, the constructed device was used to lit the 'VNIT' acronym assembled using 21 LED's

Flexible solvent-free polymer electrolytes for solid-state Na batteries

Post-lithium batteries, based on alkaline and alkaline earth elements, are cheaper technologies with the potential to produce disruptive changes in the transition towards cleaner and sustainable energy sources less dependent on fossil fuels. This contribution deals with the development and characterization of sodium-conducting solvent-free polymer electrolytes towards the attainment of Sodium Polymer Batteries. Obtained via the polycondensation of α, ω-dihydroxy-oligo(oxyethylene) with an unsaturated dihalide, whose further curing leads to amorphous networked electrolyte films. Using NaClO4 and NaCF3SO3 at different O/Na ratios, the best polymer electrolyte reaches a cationic conductivity (σ+) exceeding 1 mS cm−1 at 90 °C whereas maintaining mechanical integrity up to at least 120 °C.The authors would like to thank the Agencia Española de Investigación/Fondo Europeo de Desarrollo Regional (FEDER/UE) for funding the project PID2019-106662RBC43. This work has been supported by the Madrid Government (Comunidad de Madrid-Spain) through three projects: 1) the Multiannual Agreement with UC3M ("Fostering Young Doctors Research", CIRENAICA-CM-UC3M), and in the context of the VPRICIT (Research and Technological Innovation Regional Programme); 2) the Multiannual agreement with UC3M ("Excelencia para el Profesorado Universitario" - EPUC3M04) - Fifth regional research plan 2016-2020; 3) DROMADER-CM (Y2020/NMT6584). B.P. and A.V. acknowledge support from the CONEX-Plus programme funded by Universidad Carlos III de Madrid and the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No. 801538

Development of sodium hybrid quasi-solid electrolytes based on porous NASICON and ionic liquids

Lithium-ion batteries are currently the alternative of choice to overcome the increasing demand of energy. However, besides the scarcity of lithium and limited geolocation, it is believed that such batteries have already reached their maximum maturity. Sodium batteries emerge as an alternative to produce the new, so called, post-lithium batteries. In this study, we explore (i) the effect of sodium content and sintering temperature in solid electrolytes based in NASICON-type compounds and (ii) the use of two methodologies to obtain porous NASICON samples: application of natural substances and organic materials as pore-formers and freeze casting. The main purpose is the attainment of hybrid quasi-solid state electrolytes, with enhanced room temperature conductivity, based on porous ceramic electrolyte layers infiltrated with ionic liquids. Using this approach, porous samples with different microstructure and porous morphology and distribution were achieved, providing an enhancement in conductivity (ranging from 0.45 to 0.96 mS cm−1 at 30 °C) of one order of magnitude for infiltrated samples respect to pore-free samples. According to these results the porous NASICON might be considered as a functional macroporous inorganic separator that can act as a Na+ reservoir.The authors would like to thank the Agencia Española de Investigación /Fondo Europeo de Desarrollo Regional (FEDER/UE) for funding the projects PID2019-106662RBC43. This work has also been supported by Comunidad de Madrid (Spain) - multiannual agreement with UC3M ("Excelencia para el Profesorado Universitario" - EPUC3M04) - Fifth regional research plan 2016-2020

Ex situ conservation and qualitative characterization of traditional cultivars of rice (Oryza sativa L.)

168-179Genetic diversity of rice cultivars offers adequate opportunity for added advantage for rice improvement. Current study with 132 traditional rice cultivars had been collected from West Bengal, Manipur and Assam. Those cultivars are being preserved at repository of Uttar Banga Krishi Viswavidyalaya since 2009. Few of them had used in breeding programme to develop new desirable variety with unique characteristics. Those traditional cultivars were phenotypically characterized using PPV&FRA descriptor. In this piece of work, 44 traits were considered to record the morphological differences among the traditional cultivars. All the traditional cultivars showed one or few distinctive features that made different from each other. Finally the traditional cultivars were classified based few anticipated distinctive characters. Amylose content in endosperm was very low in ten, low in twelve, medium in 61 and high in 49 traditional cultivars. Amylose content of milled rice is a significant parameter in respect of consumer preference. Under Indian context, consumers prefer rice with medium amylose content (20-25%) in the endosperm. Strong aroma was emitted by 25, mild aroma by 23 and no aroma in 84 cultivar

Reciprocated electrochemical and DFT investigations of iron selenide: mechanically bendable solid-state symmetric supercapacitor

Enhanced energy storing capability with the aid of unique nanostructured morphology is beneficial to enrich the effective path for the development of energy storing capability of supercapacitors. Scheming earth abundant and low-cost transitional metal selenides (TMSs) with enhanced charge transfer capability with pronounced stability is still a challenge. Herein, state of art is presented for iron selenide with nanoflakes surface architecture synthesized with aid of simple, industry-scalable, and ionic layer controlled chemical approach namely; successive ionic layer adsorption and reaction (SILAR) method. Iron selenide electrode yields capacitance of 671.7 F/g at 2 mV/s scan rate and 434.6 F/g at 2 mA/cm2 current density through cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) studies, respectively with 91.9% cyclic retention at 4000 cycles. Developed bendable solid-state supercapacitor reveals remarkable power density of 5.1 kW/kg with outstanding deformation tolerance including practical demo to run small fan, demonstrating capability for advanced energy storage applications. Complementary first-principles Density Functional Theory (DFT) approach used to achieve reciprocity with experimental supercapacitive performance through the understandings of the electronic structure

Regulated electrochemical performance of manganese oxide cathode for potassium-ion batteries: A combined experimental and first-principles density functional theory (DFT) investigation

Potassium-ion batteries (KIBs) are promising energy storage devices owing to their low cost, environmental-friendly, and excellent K+ diffusion properties as a consequence of the small Stoke's radius. The evaluation of cathode materials for KIBs, which are perhaps the most favorable substitutes to lithium-ion batteries, is of exceptional importance. Manganese dioxide (α-MnO2) is distinguished by its tunnel structures and plenty of electroactive sites, which can host cations without causing fundamental structural breakdown. As a result of the satisfactory redox kinetics and diffusion pathways of K+ in the structure, α-MnO2 nanorods cathode prepared through hydrothermal method, reversibly stores K+ at a fast rate with a high capacity and stability. It has a first discharge capacity of 142 mAh/g at C/20, excellent rate execution up to 5C, and a long cycling performance with a demonstration of moderate capacity retention up to 100 cycles. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and density functional theory (DFT) simulations confirm that the K+ intercalation/deintercalation occurs through 0.46 K movement between MnIV/MnIII redox pairs. First-principles density functional theory (DFT) calculations predict a diffusion barrier of 0.31 eV for K+ through the 1D tunnel of α-MnO2 electrode, which is low enough to promote faster electrochemical kinetics. The nanorod structure of α-MnO2 facilitates electron conductive connection and provides a strong electrode–electrolyte interface for the cathode, resulting in a very consistent and prevalent execution cathode material for KIBs

Large scale flexible solid state symmetric supercapacitor through inexpensive solution processed V2O5 complex surface architecture

Complex nanostructured morphology of V2O5 has been grown on pliable stainless steel substrate (SS) through simple and inexpensive chemical bath deposition (CBD) for all-solid state flexible supercapacitor (SC). The structure and morphology of the synthesized V2O5 thin films revealed the formation of intermixed flakes. High specific capacitance of 735 F g−1 (at scan rate of 1 mV s−1) of V2O5 through liquid configuration motivated us to form complete flexible all-solid state symmetric supercapacitor (FASC) device. Remarkable specific capacitance of 358 F g−1. With 1.8 V wide potential window and high value of capacitive retention of 88% over 1000 cycles has been achieved for FASC. Furthermore, the origin of capacitive behavior from dual contributions of surface-controlled and diffusion-controlled charge components has been evaluated to identify the dominating nature in electrochemical reactions. As practical applicability, pliability of electrode has been tested at 175° bending angle along with the integration to large scale electrode dimension (11 ×4 cm2)