Na3V2(PO4)3 Cathode for Room-Temperature Solid-State Sodium-Ion Batteries: Advanced In Situ Synchrotron X-ray Studies to Understand Intermediate Phase Evolution.

Sodium-ion batteries (NIBs) can use elements that are abundantly present in Earth's crust and are technologically feasible for replacing lithium-ion batteries (LIBs). Hence, NIBs are essential components for sustainable energy storage applications. All-solid-state sodium batteries are among the most capable substitutes to LIBs because of their potential to have low price, great energy density, and consistent safety. Nevertheless, more advancements are needed to improve the electrochemical performance of the Na3V2(PO4)3 (NVP) cathode for NIBs, especially with regard to rate performance and operational lifespan. Herein, a core-shell NVP/C structure is accomplished by adopting a solid-state method. The initial reversible capacity of the NVP/C cathode is 106.6 mAh/g (current rate of C/10), which approaches the theoretical value (117.6 mAh/g). It also exhibits outstanding electrochemical characteristics with a reversible capacity of 85.3 mAh/g at 10C and a cyclic retention of roughly 94.2% after 1100 cycles. Using synchrotron-based operando X-ray diffraction, we present a complete examination of phase transitions during sodium extraction and intercalation in NVP/C. To improve safety and given its excellent ionic conductivity and broad electrochemical window, a Na superionic conductor (NASICON) solid electrolyte (Na3.16Zr1.84Y0.16Si2PO12) has been integrated to obtain an all-solid-state NVP/C||Na battery, which provides an exceptional reversible capacity (95 mAh/g at C/10) and long-term cycling stability (retention of 78.3% after 1100 cycles).

Exploring antimicrobial and biocompatible applications of eco-friendly fluorescent carbon dots derived from fast-food packaging waste transformation.

In the face of escalating environmental concerns, particularly the pervasive issue of non-biodegradable fast-food packaging waste, this study introduces a ground-breaking solution that not only addresses waste management but also advances biomedical technology. Utilizing the underexploited resource of Fucoidan, a sulfated polysaccharide from brown algae, we have innovatively transformed fast-food packaging waste into eco-friendly fluorescent carbon dots (FPCDs). These FPCDs were meticulously characterized through advanced techniques like FT-IR, TEM, and XRD, shedding light on their unique structure, morphology, and composition. A significant discovery of this study is the potent antimicrobial properties of these FPCDs, which demonstrate remarkable effectiveness against specific bacterial and fungal strains. This opens new avenues in the realm of biomedical applications, including imaging, drug delivery, and biosensing. Furthermore, extensive toxicity assessments, including the Brine shrimp lethality assay and Adult Artemia toxicity tests, underscore the safety of these nanoparticles, bolstering their applicability in sensitive medical scenarios. Our research presents a compelling dual approach, ingeniously tackling environmental sustainability issues by repurposing waste while simultaneously creating valuable materials for biomedical use. This dual benefit underscores the transformative potential of our approach, setting a precedent in both waste management and medical innovation.

Adsorption of phenol using adsorbent derived from Saccharum officinarum biomass: optimization, isotherms, kinetics, and thermodynamic study.

The present research shows the application of Taguchi's design of experiment approach to optimize the process parameters for the removal of phenol onto surface of Saccharum officinarum biomass activated carbon (SBAC) from an aqueous solution to maximize adsorption capacity of SBAC. The effect of adsorption parameters viz. adsorbent dose (m), temperature (T), initial concentration (C0) and mixing time (t) on response characteristics i.e., adsorption capacity (qt) has been studied at three levels by using L9 orthogonal array (OA) which further analyzed by variance analysis (ANOVA) for adsorption data and signal/noise (S/N) ratio data by using 'larger the better' characteristics. Using ANOVA, the optimum parameters are found to be m = 2 g/L, C0 = 150 mg/L, T = 313 K and t = 90 min, resulting in a maximum adsorption capacity of 64.59 mg/g. Adopting ANOVA, the percentage contribution of each process parameter in descending order of sequence is adsorbent dose 59.97% > initial phenol concentration 31.70% > contact time 4.28% > temperature 4.04%. The phenol adsorption onto SBAC was best fitted with the pseudo-second-order kinetic model and follows the Radke-Prausnitz isotherm model. Thermodynamic parameters suggested a spontaneous, exothermic nature and the adsorption process approaches physisorption followed by chemisorption. Hence the application of Taguchi orthogonal array design is a cost-effective and time-efficient approach for carrying out experiments and optimizing procedures for adsorption of phenol and improve the adsorption capacity of SBAC.

Influence of fly ash on thermo-mechanical and mechanical behavior of injection molded polypropylene matrix composites.

Polypropylene composites find widespread application in industries, including packaging, plastic parts, automotive, textiles, and specialized devices like living hinges known for their remarkable flexibility. This study focuses on the manufacturing of polypropylene composite specimens by incorporating varying weight percentages of fly ash particles with polypropylene using a twin-screw extruder and injection molding machine. The composites were comprehensively tested, evaluating tensile, compressive, and flexural strength, solid-state and polymer melt properties, modulus, damping, and thermal response. The findings reveal that the compressive strength of polypropylene increases up to 2 wt% of added fly ash particles and subsequently exhibits a slight decline. Tensile strength demonstrates an increase up to 1 wt% of fly ash, followed by a decrease with a 2 wt% addition, and then a subsequent increase. Flexural strength shows improvement up to 3 wt% fly ash addition before declining. The storage modulus curve is categorized into three regions: the glassy region (up to 0 °C), the glass transition region (0-50 °C), and the glass transition region of polypropylene (>50 °C), each corresponding to different molecular motions. Weight loss curves exhibit similar trends, indicating uniform pyrolysis behavior attributed to consistent chemical bonds. Plastic degradation commences around 440 °C and concludes near 550 °C. Additionally, elemental mapping of fly ash composition identified various elements such as O, Si, K, Mg, Ca, Cl, Na, P, Al, Fe, S, Cu, Ti, and Ni. These findings offer valuable insights into the mechanical and thermal properties of polypropylene composites reinforced with fly ash, rendering them suitable for a wide range of industrial applications necessitating strength and durability across temperature variations.

Fe-phthalocyanine derived highly conjugated 2D covalent organic framework as superior electrocatalyst for oxygen reduction reaction.

Although porphyry systems like metallo-phthalocynine are recognized as promising molecular models for electrocatalytic oxygen reduction reaction (ORR), their poor durability and methanol tolerance are still challenges and need improvement before being considered for practical applications. Herein, we successfully designed and constructed a Fe-phthalocyanine-derived highly conjugated 2D covalent organic framework (2D FePc-COF), using octa-amino-Fe-phthalocyanine (OA-FePc) and cyclohexanone as precursors. The prepared 2D FePc-COF was characterized via multiple analytic techniques. The electrochemical studies indicated that prepared 2D FePc-COF was far more superior to OA-FePc and 20% Pt/C, displaying anodic shift of 100 and 50 mV (vs RHE) in formal potential, respectively. Moreover, this catalyst also demonstrated excellent methanol tolerance and durability (over 10,000 CV cycles). Theoretical investigations revealed that due to extended conjugation and elimination of electron donating groups (-NH2), the shifting of dz2-orbital (Fe) energy took nearer to π*-orbital (O2), allowing optimum coupling of both the orbitals, thereby enhancing 4e- ORR. This work demonstrates the art of molecular design, aiming at improving catalytic activity of macrocyclic molecular systems towards ORR.

Sustainable preparation of luminescent carbon dots from syringe waste and hyaluronic acid for cellular imaging and antimicrobial applications.

Addressing the global challenge of persistent waste through an eco-conscious strategy to transform it into valuable and versatile materials holds great significance in today's swiftly evolving world. By adopting a sustainable approach, we can repurpose waste syringes composed of polytetrafluoroethylene (PTFE) into fluorescent carbon dots (CDs) using a simple hydrothermal process. This research harnessed hyaluronic acid to carbonize and modify discarded plastic syringes, resulting in the creation of luminescent syringe carbon dots (SCDs). Rigorous analysis employing diverse techniques delved into their optical attributes, size distribution, and surface characteristics. Extensive biocompatibility assessments using established assay methods confirmed the safety of the derived SCDs, unveiling their potential antibacterial and antifungal traits. Additionally, a confocal microscope was employed to evaluate the cellular imaging capabilities of SCDs on HeLa cells. Notably, at bactericidal concentrations, SCDs exhibited mild cytotoxicity towards mammalian cells, showcasing cell viability surpassing 91.07% at 1 mg/mL. This pioneering exploration paves the way for potential applications of SCD-based nano-bactericides across various biomedical domains. The initial outcomes established herein mark a significant stride towards the creation of cost-effective and ecologically sound fluorescent probes for biomedical imaging, aimed at combating microbial infections. By ingeniously reutilizing polyethylene terephthalate (PET), this investigation offers a sustainable remedy to address the ecological predicaments linked with plastic waste. In doing so, it charts a course towards contributing to the development of affordable, eco-friendly solutions, heralding a promising prospect for a cleaner, healthier environment.

A NiS2/C composite as an innovative anode material for sodium-ion batteries: ex situ XANES and EXAFS studies to investigate the sodium storage mechanism.

The successful deployment of sodium-ion batteries (SIBs) requires high-performance sustainable and cost-effective anode materials having a high current density. In this regard, sodium disulphide (NiS2) has been prepared as a composite with activated carbon (C) using a facile hydrothermal synthesis route in the past. The X-ray diffraction pattern of the as-prepared NiS2/C composite material shows well-defined diffraction peaks of NiS2. Most carbonaceous materials are amorphous, and the Brunauer-Emmett-Teller (BET) study shows that the surface area is close to 148 m2 g-1. At a current density of 50 mA g-1, the NiS2/C composite exhibits a high capacity of 480 mA h g-1 during the initial cycle, which subsequently decreases to 333 mA h g-1 after the completion of the 100th cycle. The NiS2/C composite electrode provides an exceptional rate capability by delivering a capacity of 270 mA h g-1 at a high current density of 2000 mA g-1, suggesting the suitability of the NiS2/C composite for SIBs. Ex situ X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) analyses at the Ni K-edge have been used to examine the type of chemical bonding present in the anode and also how it changes during electrochemical redox cycling. The understanding of the sodium storage mechanism is improved by the favorable results, which also offer insights for developing high-performance electrode materials for rechargeable SIBs.

Ziziphus mauritiana-derived nitrogen-doped biogenic carbon dots: Eco-friendly catalysts for dye degradation and antibacterial applications.

In this study, the naturally available Ziziphus Mauritiana was used as a bioresource for the preparation of bifunctional nitrogen doped carbon dots (N-CDs). The doping of nitrogen into the graphitic carbon skeleton and the in-situ formation of N-CDs were systematically identified by the various structural and morphological studies. The green fluorescent N-CDs were used as active catalysts for the removal of Safranin-O dye and achieved 79 % removal efficiency. Furthermore, the prepared N-CDs were used to evaluate antibacterial activity with four different bacterial species, such as Shigella flexneri, Staphylococcus aureus, Streptococcus pyogenes, and Klebsiella pneumoniae. Amongst these, the highest antimicrobial activity was achieved against Klebsiella pneumonia, with a maximum zone of inhibition of 14.6 ± 1.12 at a concentration of 100 g mL-1. Thus, the obtained results demonstrate the cost efficient bifunctional application prospects of N-CDs to achieve significant catalytic and antibacterial activities.

Characteristics estimation of natural fibre reinforced plastic composites using deep multi-layer perceptron (MLP) technique.

Polymer Matrix Composite (PMC/Plastic Composite) often referred to as Plastic Composite with Natural fibre reinforcement has a huge interest in industries to manufacture components for various applications including medical, transportation, sports equipment etc. In the universe, different types of natural fibres are available which can be used for the reinforcement in PMC/Plastic Composite. So, the selection of appropriate fibre for the PMC/Plastic Composite/Plastic composite is a challenging task, but it can be done using an effective metaheuristic or optimization techniques. But in this type of optimal reinforcement fibre or matrix material selection, the optimization is formulated based on any one of the parameters of the composition. Hence to analyse the various parameter of any PMC/Plastic Composite/Plastic Composite without real manufacturing, a machine learning technique is recommended. The conventional simple or single-layer machine learning techniques were not sufficient to emulate the exact real-time performance of the PMC/Plastic Composite. Thus, a deep multi-layer perceptron (Deep MLP) algorithm is proposed to analyse the various parameter of PMC/Plastic Composite with natural fibre reinforcement. In the proposed technique the MLP is modified by including around 50 hidden layers to enhance its performance. In every hidden layer, the basis function is evaluated and subsequently, the sigmodal function-based activation is calculated. The proposed Deep MLP is utilized to evaluate the various parameters of PMC/Plastic Composite Tensile Strength, Tensile Modulus, Flexural Yield Strength, Flexural Yield Modulus, Young's Modulus, Elastic Modulus and Density. Then the obtained parameter is compared with the actual value and the performance of the proposed Deep MLP is evaluated based on the accuracy, precision, and recall. The proposed Deep MLP attained 87.2%, 87.18%, and 87.22% of accuracy, precision, and recall. Ultimately the proposed system proves that the proposed Deep MLP can perform better for the prediction of various parameters of PMC/Plastic Composite with natural fibre reinforcement.

Correction: Immobilized Ni on TMEDA@ßSiO2@αSiO2@Fe3O4: as a novel magnetic nanocatalyst for preparation of pyrido[2,3-d:6,5-d']dipyrimidines.

[This corrects the article DOI: 10.1039/D3RA01720F.].

Immobilized Ni on TMEDA@ßSiO2@αSiO2@Fe3O4: as a novel magnetic nanocatalyst for preparation of pyrido[2,3-d:6,5-d']dipyrimidines.

In the current body of research, a very quick and effectual procedure for the synthesis of pyrido[2,3-d:6,5-d']dipyrimidines has been developed. This method is accomplished through the one-pot multi-component reaction of 2-thiobarbituric acid, NH4OAc and aldehydes utilizing Ni-TMEDA@ßSiO2@αSiO2@Fe3O4 as a novel mesoporous nanomagnetic catalyst at room temperature. This protocol is one of the few reports of the preparation of these derivatives without the use of conventional heating as well as energies such as microwave and ultrasound radiation. The characterization of the prepared catalyst was well accomplished by different techniques such as FT-IR, ICP-OES, SEM, TEM, BET, XRD, VSM, TGA, EDX and Elemental mapping. This organometallic catalyst was reusable for seven times with negligible decrement in its catalytic performance. In addition, all of the products were produced with high TON and TOF values, which demonstrates that our catalyst has a very high level of activity in the preparation of pyrido[2,3-d:6,5-d']dipyrimidines.

Synergy of silica sand and waste plastics as thermoplastic composites on abrasive wear characteristics under conditions of different loads and sliding speeds.

The diverse nature of polymers with attractive properties has replaced the conventional materials with polymeric composites. The present study was sought to evaluate the wear performance of thermoplastic-based composites under the conditions of different loads and sliding speeds. In the present study, nine different composites were developed by using low-density polyethylene (LDPE), high-density polyethylene (HDPE) and polyethylene terephthalate (PET) with partial sand replacements i.e., 0, 30, 40, and 50 wt%. The abrasive wear was evaluated as per the ASTM G65 standard test for abrasive wear through a dry-sand rubber wheel apparatus under the applied loads of 34.335, 56.898, 68.719, 79.461 and 90.742 (N) and sliding speeds of 0.5388, 0.7184, 0.8980, 1.0776 and 1.4369 (m/s). The optimum density and compressive strength were obtained to be 2.0555 g/cm3 and 46.20 N/mm2, respectively for the composites HDPE60 and HDPE50 respectively. The minimum value of abrasive wear were found to 0.02498, 0.03430, 0.03095, 0.09020 and 0.03267 (cm3) under the considered loads of 34.335, 56.898, 68.719, 79.461 and 90.742 (N), respectively. Moreover, the composites LDPE50, LDPE100, LDPE100, LDPE50PET20 and LDPE60 showed a minimum abrasive wear of 0.03267, 0.05949, 0.05949, 0.03095 and 0.10292 at the sliding speeds of 0.5388, 0.7184, 0.8980, 1.0776 and 1.4369 (m/s), respectively. The wear response varied non-linearly with the conditions of loads and sliding speeds. Micro-cutting, plastic deformations, fiber peelings, etc. were included as the possible wear mechanism. The possible correlations between wear and mechanical properties, and throughout discussions for wear behaviors through the morphological analyses of the worn-out surfaces were provided.

Regulation of ash slagging behavior of palm oil decanter cake by alum sludge addition.

Combustion of palm oil decanter cake (PODC) is a propitious alternative waste to energy means. However, the mono-combustion of PODC prompt severe ash slagging behavior which give rise to reduction in heat transfer and also shorten the lifespan of combustion reactors. In this study, alum sludge (AS) was introduced at different proportion of 30%, 50% and 70% to revamp the slagging characteristics of PODC during combustion. The addition of AS improved ash fusion temperature of PODC during co-combustion as ash fusion temperature increased significantly under high AS dosage. Slagging and fouling indices showed that at 50% AS addition, slagging tendency of the co-combustion ashes can be ignored. The predictive model for PODC-AS combustion showed good correlation coefficient with 0.89. Overall, co-combustion of PODC and AS is an ideal ash related problem-solving route. The proposed PODC slagging preventive method by AS was based on: (1) limited amount of aluminum content in PODC-AS system resulted in development of refractory ash (2) reduction in proportion of basic oxide which act as ash bonding glue played important role in the regulation of slagging (3) reduction of cohesive bond by formation of spongy and porous structure which prevented ash slagging.

Agricultural waste to real worth biochar as a sustainable material for supercapacitor.

Biochar made from agricultural waste is gaining more attention in energy field due to its sustainability, low cost, apart from having high supercapacitance performance. Also, it has a wide range of environmental applications, including wastewater treatment, upgrading soil fertility, contaminant immobilization, and in situ carbon sequestration. The existing thermo-chemical methodologies for converting agricultural waste into a sustainable material i.e. biochar and the role of activation agents in enhancing the performance of these materials were critically analyzed and discussed. An overview of recent trends in agricultural waste-derived biochar for supercapacitor electrodes is highlighted in this review that emphasizes green circular economy for encouraging net-zero utility of agriculture waste biomass. The roles of various newly prepared "green" electrolytes in reducing the negative consequences of supercapacitor is also reviewed. The trashing of agricultural waste and the depletion of energy supplies has become a global concern, hurting the world's ecosystem and economy through pollution and a fuel crisis and hence the concept of a green circular economic model is also highlighted.

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.

Flower-like nickel hydroxide@tea leaf-derived biochar composite for high-performance supercapacitor application.

Renewable and sustainable high-performance energy storage devices are desirable to fulfill the demands of next-generation power sources. In this study, we report a flower-like nickel hydroxide/spent tea leaf-derived biochar (NiNF@TBC) composite for high-performance supercapacitor application. The tea leaf-derived biochar (TBC) with a specific surface area of 1340 m2 g-1 is used as the Ni(OH)2 support to fabricate NiNF@TBC composites. The highly porous and hierarchical structure of the as-synthesized NiNF@TBC composite facilitates the electrolyte ion and electron diffusion and transport more readily. As a result, the decrease in diffusion path and the increase in conductivity of NiNF@TBC for energy storage applications. The NiNF@TBC electrode shows excellent electrochemical properties with a specific capacitance of 945 F g-1 at 1 A g-1 in a three-electrode cell and high stability of 95% after 10,000 cycles. Moreover, the symmetric supercapacitor fabricated with NiNF@TBC delivers a specific capacitance of 163 F g-1 in 1 M Na2SO4 solution. The Ragone plot of the symmetric device exhibits energy density in the range of 19 - 58 Wh kg-1 with power density in the scale of 826 - 6321 W kg-1. An excellent long-term cyclic stability of 94% is obtained after 10,000 charge-discharge cycles. Such an excellent performance has demonstrated the feasibility of utilizing agricultural wastes as green carbon sources, which can combine with various metal hydroxides to produce hybrid nanomaterials as a highly potential electrode material for green sustainable supercapacitor applications.

N-methylene phosphonic acid chitosan/graphene sheets decorated with silver nanoparticles as green antimicrobial agents.

A green and scalable approach for the preparation of few-layered graphene utilizing the biowaste of potato peels has been developed. The potato peels have been dried and carbonized to obtain a new graphite structure that has been exfoliated in N-methylene phosphonic acid chitosan (MPC). The exfoliation process assisted the formation of graphene sheets with a high size diameter and quality of 50% based on the weight of graphite structure. The graphene sheets were green decorated with silver nanoparticles using microwave power to obtain new nanocomposites. The mass ratio between the graphite and silver nitrate was optimized and observed to change the morphology and size diameter of silver nanoparticles. The as-prepared MPC structure, graphene, and silver decorated graphene nanocomposites were characterized using 1HNMR, FTIR, XRD, UV/Vis spectrophotometer, SEM, and TEM besides tested as antimicrobial agents. The bacterial performance was also controlled by changing the number of AgNPs distributed on graphene sheets based on the mass ratios of graphite/AgNO3. The inhibition diameter of silver decorated graphene was considerably increased to 24.8, and 20.1 mm as in the case of MPC-GRP-Ag30 composite compared to the pure graphene (11.2, 13.5 mm) for E. coli and S. aureus, consecutively proposing that the blade edge of graphene sheets can destroy the bacteria membrane and release silver cations promptly that are directed for the interaction with the cytoplasmic parts of the bacteria cell. Such findings offer green and biocompatible antibacterial agents based on the graphene derived from the biowaste products.

High Stability and Long Cycle Life of Rechargeable Sodium-Ion Battery Using Manganese Oxide Cathode: A Combined Density Functional Theory (DFT) and Experimental Study.

Sodium-ion batteries (SIBs) can develop cost-effective and safe energy storage technology for substantial energy storage demands. In this work, we have developed manganese oxide (α-MnO2) nanorods for SIB applications. The crystal structure, which is crucial for high-performance energy storage, is examined systematically for the metal oxide cathode. The intercalation of sodium into the α-MnO2 matrix was studied using the theoretical density functional theory (DFT) studies. The DFT studies predict Na ions' facile diffusion kinetics through the MnO2 lattice with an attractively low diffusion barrier (0.21 eV). When employed as a cathode material for SIBs, MnO2 showed a moderate capacity (109 mAh·g-1 at C/20 current rate) and superior life cyclability (58.6% after 800 cycles) in NaPF6/EC+DMC (5% FEC) electrolyte. It shows a much higher capacity of 181 mAh·g-1 (C/20 current rate) in NaClO4/PC (5% FEC) electrolyte, though it suffers fast capacity fading (11.5% after 800 cycles). Our findings show that high crystallinity and hierarchical nanorod morphology of the MnO2 are responsible for better cycling performance in conjunction with fast and sustained charge-discharge behaviors.

The electrochemical kinetics of cerium selenide nano-pebbles: the design of a device-grade symmetric configured wide-potential flexible solid-state supercapacitor.

Next-generation portable flexible electronic appliances require liquid-free energy storage supercapacitor devices to eliminate leakage and to support mechanical bending that is compatible with roll-to-roll technologies. Hence, a state-of-the-art process is presented to design a solid-state, wide-potential and flexible supercapacitor through the use of nano-pebbles of cerium selenide via a simple successive ionic layer adsorption and reaction (SILAR) method that could allow an industry scalable route. We strongly believe that this is the first approach amongst physical and chemical routes not only for synthesizing cerium selenide in thin-film form but also using it for device-grade supercapacitor applications. The designed solid-state symmetric supercapacitor assembled from cerium selenide electrodes sandwiched by PVA-LiClO4 gel electrolyte attains a wide potential window of 1.8 V with capacitance of 48.8 F g-1 at 2 mV s-1 and reveals excellent power density of 4.89 kW kg-1 at an energy density of 11.63 W h kg-1. The formed device is capable of 87% capacitive retention even at a mechanical bending angle of 175°. Lighting up a strip of 21 parallel connected red LEDs clearly demonstrates the practical use of the designed symmetric solid-state supercapacitor, aiming towards the commercialization of the product in the future.

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.