Charge-discharge Cycles Research Articles

Synergistic electrochemical performance of textile sludge based activated carbon with reduced graphene oxide as electrode for supercapacitor application

The procedure for disposing of textile waste sludge requires sustainable solutions due to numerous environmental issues associated with its disposal. The majority of textile manufacturers incinerate the waste sludge to meet their heating demands, which is harmful to the environment. It can also be used in soil amendment, biodegradable products, construction material and water treatment process as absorbent to remove the heavy metals etc. In this study we use the heavy metal containing textile waste sludge as a precursor for the fabrication of functional electrode material for supercapacitor applications. In this process the organic content within the textile sludge waste is treated at 900 °C and transformed into activated carbon, a vital component of supercapacitors electrodes. Through a series of pyrolysis and activation processes, it is further converted into porous activated carbon (AC) with a wide surface area and appropriate electrochemical properties. To enhance the overall conductivity of the electrode material for supercapacitor applications, the carbon content of the material is increased by loading of reduced graphene oxide (rGO) up to 4 wt%. It resulted in a significant increase in the surface area up to 128.68 m2/g. The effective conversion and relevance of the obtained material for supercapacitor applications is further reinforced by the excellent electrochemical performance of rGO@AC-900 °C which generated a specific capacitance of 362F/g with 4 wt% loading which is higher than the specific capacity achieved with lower rGO loading i.e., 83.2 F/g and 182.5 F/g for AC-900 °C and 2 wt% rGO@AC-900 °C, respectively. The 4 wt% rGO@AC900°C also represented improved stability with up to 82 % charge retention after 5000 charge–discharge cycles. The excellent EDLC behavior of 4 wt% rGO@AC900°C is also evident from the impedance data. The electrode material with 4 wt% rGO loading showed lower value of RCT i.e., 4.16 Ω as compared to 12.08 Ω with 2 wt% rGO loading. This novel approach offers a sustainable alternative for the handling of hazardous textile waste sludge through conversion into a potential electrode material for environmentally friendly energy storage devices.

The heating effect analysis of electromagnetic induction heating system based on the multi objective optimization strategy

Lithium-ion battery heating in cold weather is necessary to ensure its low-temperature performance and lifetime, so the multi objective optimization heating strategy based on the non-dominated sorting genetic algorithm II is introduced to improve the heating effect of electromagnetic induction heating system, in which the generated Pareto frontier as the research sample is input in K-medoid algorithm in order to reduce the feasible range of solution sets and then get the optimal induction coil parameters combination, and the temperature rise and terminal voltage output performance of battery are characterized by the electrochemical-thermal coupling model. Firstly, under the optimal parameters combination (N = 180, f = 9 kHZ, IA = 6 A), the battery can be heated from 243.15 K to 293.15 K in 1430 s with the temperature difference of 2.74 K, and the temperature field is mainly generated by the heat conduction from active material to mandrel during the heating process due to skin effect and material property. Secondly, the internal resistance is decreased by more than 3 times after the heating, giving rise to the substantial improvement of energy output ability. Finally, neither noticeable discharging capacity retention loss nor apparent voltage output difference is founded after the 200 repeated heating cycles, as compared with the normal charging-discharging cycle at 293.15 K, so the heating strategy has almost no effect on the battery aging and lifetime deterioration. Therefore, the proposed heating strategy can realize a suitable tradeoff among temperature-rising effect, lifespan and low-temperature operating performance, which has substantial potential to be a feasible method for improving the applicability of electric vehicles in a cold weather.

DC-DC Buck Converters with Quasi-Online Estimation of Filter Capacitor Equivalent Parameters

The article focuses on devising solutions for monitoring the condition of the filter capacitors of DC-DC converters. The article introduces two novel DC-DC buck converter designs that monitor the equivalent series resistance (ESR) and the capacitance of capacitors using a parameter observer (PO) and simple variable electrical networks (VEN). For the first scheme, the PO processes in real time the voltage at the capacitor terminals during a discharge-charge cycle. For the second scheme, the filtering is performed with two or more capacitors in parallel, and the PO processes the voltage at the terminals of each capacitor during two discharge processes without interrupting the filtering operation of the converter. The paper presents the principles and theoretical support on which the two schemes of DC-DC buck converters are based, design details regarding PO and VEN, as well as experiments performed with each of the schemes. In the experimental schemes, the PO is implemented with a microcontroller, and the parameters of some aluminum electrolytic filter capacitors are calculated in a real-time manner of about . The calculation accuracy of the equivalent capacity is very good. Regarding the calculation accuracy of the ESR, it is shown that it depends on the fulfillment of certain ratios between the VEN resistances, on the one hand, as well as between them and the ESR, on the other hand.

Classification and Analysis of Halide Mixtures in Li10P3S12M (M = Cl, Br, I) Solid Electrolytes for Superionic Conductors.

The lithium thiophosphate group of solid electrolytes (SEs) is considered one of the best lithium-ion conductors that could be compatible with liquid electrolytes. However, the interface stability of lithium thiophosphate SEs against the lithium anode and oxide cathode could be a challenge due to severe degradation over charge-discharge cycles. In this study, we aim to analyze and introduce the addition of halides into lithium thiophosphate SEs with a molar ratio of 3Li3PS4 to 1LiM (M = Cl, Br, I) in order not only to improve ion conductivity but also to increase the interface stability of the SEs. Li10P3S12Br (LPSBr) and Li10P3S12I (LPSI) results in high ionic conductivity at 1.7 and 2.9 mS cm-1, respectively, at room temperature. Although LPSBr has lower ion conductivity, it shows better electrochemical stability compared to LPSI. By combining the advantages of both LiI and LiBr to form Li10P3S12Br1-xIx, we have observed improvements not only in high ionic conductivity but also in the interface stability of SEs, which is important for extending the lifetime cycle of all-solid-state lithium batteries (ASSLBs).

N/S co-doped nanocomposite of graphene oxide and graphene-like organic molecules as all-carbonaceous anode material for high-performance Li-ion batteries

In this study, to enhance the electrochemical performance of graphene-based anodes for Li-ion batteries (LIBs), we synthesized an all-carbonaceous N/S co-doped nanocomposite of graphene oxide (GO) and graphene-like small organic molecules (GOM) using a mild, eco-friendly, one-step hydrothermal method with thiourea (CH4N2S) (denoted as h-N/S-GO/GOM). The thiourea facilitated N/S co-doping and π−π bonding, which improved the interaction between hydrophilic GO and hydrophobic GOM in aqueous solution. Notably, the formation of π−π bonds between GO and GOM created pathways that enhanced electron transfer, thereby promoting efficient Li-ion transport from the electrolyte through the channels during rapid charge–discharge cycles. Additionally, the functional groups resulting from N/S co-doping increased the number of active sites within the nanocomposite. Consequently, the h-N/S-GO/GOM anode demonstrated superior electrochemical performance, achieving an average reversible capacity of 1265 mAh g−1 at 0.1 A g−1 and retaining 83.0 % of its capacity after 200 cycles. Furthermore, the nanocomposite exhibited excellent long-term cycling stability, maintaining a capacity of 688 mAh g−1 even after 1000 cycles at a high current density of 1.0 A g−1. The hierarchical network structure of the all-carbonaceous h-N/S-GO/GOM anode facilitated efficient charge transfer between the electrode and electrolyte through shorter diffusion paths for Li-ion transport and provided additional active sites, contributing to its outstanding electrical performance. The h-N/S-GO/GOM nanocomposite represents a promising alternative to traditional graphite-based anodes, offering a path toward high-performance, eco-friendly LIBs suitable for applications such as electric vehicles and energy storage systems.

Synthesis of Fe₃O₄/FeS₂ composites via MOF-templated sulfurization for high-performance hybrid supercapacitors

The development of advanced anode materials for supercapacitors is crucial for driving innovation in the field of new energy technologies. Although iron-based materials exhibit significant potential, their electrical conductivity and cyclic stability remain challenges. In this study, Fe3O4/FeS2 composites were successfully synthesized using a sacrificial MOF template and a solid-state sulfurization process. The composite preserved the original morphology of Fe-MOF, while numerous nanoscale particles were generated through heterogeneous sulfurization. Notably, the SMFO-2 composite exhibited a specific capacity of 208.5 mAh g−1 at a current density of 1 A g⁻¹. When integrated into a hybrid supercapacitor (HSC) with SMFO-2 serving as the anode and super-electric activated carbon (AC) as the cathode, the device exhibited excellent electrochemical performance. Specifically, it achieved a capacity retention rate of 78.6 % after 10,000 charge-discharge cycles at 2 A g⁻¹. Furthermore, the HSC achieved an optimal energy density of 28.8 Wh kg⁻¹ at a power density of 375 W kg⁻¹, successfully powering a small bulb, highlighting its strong potential of the Fe3O4/FeS2 composite for real-world practical applications.

Gallium hydroxide coated Ti3C2Tx MXene for high-performance asymmetric supercapacitor

Ti3C2Tx MXenes have emerged as promising candidates for energy storage applications due to their two-dimensional structure, metallic conductivity, tunable surface functionalities, and intrinsic pseudocapacitive charge storage. This study explores the hydrothermal synthesis of GaOOH/Ti3C2Tx composites using gallium nitrate as the gallium precursor. The incorporation of GaOOH not only expands the interlayer spacing of Ti3C2Tx, facilitating more efficient electrolyte ion migration, but also enhances the material's energy storage capacity by introducing additional active sites and augmenting pseudocapacitance. As an electrode material in supercapacitors, GaOOH/Ti3C2Tx composites, prepared with a 0.06 M gallium source concentration, achieve a remarkable specific capacitance of 542.1 F·g−1, surpassing that of pristine Ti3C2Tx (305 F·g−1), with a minimal degradation of only 3.4 % after 5000 charge-discharge cycles. This research offers valuable insights into the electrochemical behavior of GaOOH/Ti3C2Tx composites and highlights the role of GaOOH in enhancing the performance of these materials. The results underscore the potential of combining metal hydroxides with MXenes for advanced supercapacitor applications.

In-situ reduced Cu3N nanocrystals enable high-efficiency ammonia synthesis and zinc-nitrate batteries.

Nitrate reduction reaction (NO3RR) involves an 8-electron transfer process and competes with the hydrogen evolution reaction process, resulting in lower yields and Faraday efficiency (FE) in the process of NH3 synthesis. Especially, Cu-based catalysts (Cu0 and Cu+) have been investigated in the field of NO3RR due to the energy levels of d-orbital and the least unoccupied molecular orbital (LUMO) π* of nitrate's orbital. Based on the above, we synthesized a Cu-based compound containing Cu3N (Cu+) through a simple one-step pyrolysis method, applied it to electrocatalytic NO3RR, and tested the performance of the Zn-NO3- battery. Through various characterization analyses, Cu-based catalysts (Cu+) are the key active sites in reduction reactions, making Cu3N a potential catalyst for ammonia synthesis. The research results indicate the application of Cu3N catalyst in NO3RR shows the best NH3 yield of 173.7 μmol h-1 cm-2, with FENH3 reaching 91.0% at -0.3 V vs. RHE, which is much higher than that of Cu catalyst without N. In addition, the Zn-NO3- battery based on Cu3N electrode also exhibits an NH3 yield of 39.8 μmol h-1 cm-2, 63.0% FENH3, and a power density of 2.7 mW cm-2, as well as stable cycling charge-discharge stability for 5 hours.

State-of-Health Estimation for Lithium-Ion Batteries in Hybrid Electric Vehicles—A Review

This paper presents a comprehensive review of state-of-health (SoH) estimation methods for lithium-ion batteries, with a particular focus on the specific challenges encountered in hybrid electric vehicle (HEV) applications. As the demand for electric transportation grows, accurately assessing battery health has become crucial to ensuring vehicle range, safety, and battery lifespan, underscoring the relevance of high-precision SoH estimation methods in HEV applications. The paper begins with outlining current SoH estimation methods, including capacity-based, impedance-based, voltage and temperature-based, and model-based approaches, analyzing their advantages, limitations, and applicability. The paper then examines the impact of unique operating conditions in HEVs, such as frequent charge–discharge cycles and fluctuating power demands, which necessitate tailored SoH estimation techniques. Moreover, this review summarizes the latest research advances, identifies gaps in existing methods, and proposes scientifically innovative improvements, such as refining estimation models, developing techniques specific to HEV operational profiles, and integrating multiple parameters (e.g., voltage, temperature, and impedance) to enhance estimation accuracy. These approaches offer new pathways to achieve higher predictive accuracy, better meeting practical application needs. The paper also underscores the importance of validating these estimation methods in real-world scenarios to ensure their practical feasibility. Through systematic evaluation and innovative recommendations, this review contributes to a deeper understanding of SoH estimation for lithium-ion batteries, especially in HEV contexts, and provides a theoretical basis to advance battery management system optimization technologies.

Enhancing Supercapacitor Performance of NiCoMn‐Layered Double Hydroxide with Ag–Citrate/Polyaniline Nanocomposites

Layered double hydroxide (LDH) has a layered structure, which makes it a strong candidate for supercapacitors (SC) due to its high surface area. However, they suffer from low conductivity due to insufficient charge transfer across their layers. This research aims to overcome this obstacle by introducing conductive channels among the layers by the addition of Ag–citrate and polyaniline (PANI). Consequently, five electrodes (S1–5) were made from NiCoMn LDH (referred to as LDH henceforth) and 2:1 Ag–citrate and PANI composite (Ag/PANI) in different ratios and made into electrodes. Electrochemical analysis revealed successful improvement in the performance of LDH as the fraction of Ag/PANI increased until it equaled Ag/PANI where the highest specific capacitance of 617 F g−1 was obtained, which is 12% greater than the value for solely LDH electrode (550 F g−1). A device was fabricated with the best electrode (S3) and activated carbon electrode, which demonstrated energy densities and power densities of 41 WhKg−1 and 412.5 W Kg−1 and 14 WhKg−1and 8250 W Kg−1 at 0.5 and 10 A g−1 current densities, respectively. It also exhibited a capacitive retention of about 75% at 3000 galvanostatic charge–discharge cycles. These results encourage the use in of NiCoMn LDH, in a 1:1 ratio with Ag/PANI in SCs due to its remarkable performance.

Investigating the Effect of Carbon Nanotubes Decorated SmVO4-MoS2 Nanocomposite for Energy Storage Enhancement via VARTM-Fabricated Solid-State Structural Supercapacitors Using Woven Carbon Fiber.

Traditional supercapacitors are cumbersome and need separate enclosures, which add weight and reduce space efficiency. In contrast, structural supercapacitors combine energy storage with load-bearing materials, optimizing space and weight for automotive and aerospace applications. This study investigates the synthesis of SmVO4-MoS2 and SmVO4-MoS2-CNT nanocomposites, focusing on optimizing CNT concentration in SmVO4-MoS2-CNT for high-performance supercapacitors. The optimal concentration of SmVO4-MoS2-CNT is identified and used to fabricate structural supercapacitor devices via the vacuum-assisted resin transfer molding (VARTM) technique. The results indicate that the specific capacitance of Sm-Mo-C5, using a three-electrode system, reached 1.01Fcm-2 at a current density of 2.187mAcm-2. The performance improvement is attributed to the synergistic interaction among SmVO4, MoS2, and CNTs, collectively enhancing conductivity and active site availability. The practical application of this study is demonstrated by synthesizing Sm-Mo-C5 on woven carbon fiber (WCF) and subsequently fabricating a structural supercapacitor device (SSD) using the VARTM. The SSD, produced via VARTM, exhibited a specific capacitance of 0.287Fcm- 2 at a current density of 2Acm-2. The device showcased exceptional cyclic stability, maintaining 72.5% of its initial capacitance after 50,000 charge-discharge cycles. Additionally, it achieved a maximum energy density of 79.86Whkg-1 at a power density of 1017.69Wkg-1.

Preparation and Study of Poly(Vinylidene Fluoride-Co-Hexafluoropropylene)-Based Composite Solid Electrolytes

Solid-state electrolytes are widely anticipated to revitalize lithium-ion batteries with high energy density and safety. However, low ionic conductivity and high interfacial resistance at room temperature pose challenges for practical applications. This study combines the rigid oxide electrolyte LLZTO with the flexible polymer electrolyte poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) to achieve effective coupling of rigidity and flexibility. The semi-interpenetrating network structure endows the PEL composite solid electrolyte with excellent lithium-ion transport capabilities, resulting in an ionic conductivity of up to 5.1 × 10−4 S cm−1 and lithium-ion transference number of 0.41. The assembled LiFePO4/PEL/Li solid-state battery demonstrates an initial discharge capacity of 132 mAh g−1 at a rate of 0.1 C. After 100 charge–discharge cycles, the capacity retention is 81%. This research provides a promising strategy for preparing composite solid electrolytes in solid-state lithium-ion batteries.

Remarkably Boosted High‐Temperature Electrostatic Energy Storage of Polyetherimide Film Induced by TiO2@Au@AlOx@Au Core‐shell Nanofibers

AbstractPolymer dielectrics have broad applications in advanced electronics and power systems. However, they suffer from low energy density and poor breakdown performance at high temperatures, limiting their applications in high‐temperature environments. Herein, TiO2@Au@AlOx@Au nanofibers with double coulomb blockade nanolayers are obtained via a physical sputtering strategy to improve the high‐temperature energy storage performance of polyetherimide composites. Experimental studies and finite elemenet phase‐field simulations demonstrate that the double‐layer coulomb blockade effect and micro‐capacitor effect of Au nanoparticles synergistically enhance the breakdown strength and dielectric permittivity of polyetherimide composite at high temperatures. Notably, the composite exhibits ultra‐high discharged energy densities of 11.33 and 9.70 J cm−3 at 150 and 200 °C, respectively, along with high charge–discharge efficiencies of 93.4% and 84%, which far exceed that of the polymer nanocomposites reported so far. Furthermore, the composite exhibits excellent charge–discharge cycling performance (>50000 cycles at 400 MV m−1) and high‐power density (1.16 MW cm−3) at 200 °C, making it an ideal candidate for high‐temperature capacitors. Hopefully, these nanofibers not only serve as excellent nanofillers for high‐temperature energy storage dielectric composites but also holds tremendous potential and inspirational significance for other applications such as electronics, biomedical fields, optics, and catalysis.

Integration of Pre‐Activated Carbon‐Fabric Layers for Ampere‐Hour‐Scale Quasi‐Solid‐State Pouch‐Type Zinc–Air Batteries

AbstractAchieving ampere‐hour‐scale capacities in pouch‐type zinc–air batteries (ZABs) requires optimizing key factors, such as preventing inactive ZnO dendrite formation on zinc anodes and enhancing catalytic activity with efficient gas diffusion in the air cathode. Here, a pioneering flexible, large‐area, ampere‐hour‐scale quasi‐solid‐state ZAB is introduced, addressing these challenges through a novel preactivation strategy combined with a layered assembly approach. This method employs mass‐producible fibrous carbon textiles to form flexible fabrics that separate functions within multi‐stacked layers. Preactivated carbon fabric layers, independently functionalized and easily reassembled, enhance scalability and manufacturability. A bilayer catalytic air electrode, incorporating hydrophilic NiFe hydroxide and hydrophobic FeNC regions, ensures efficient charge and mass transfer, significantly boosting catalytic activity. To prevent dendrite formation on the zinc anode, a zincophilic copper interlayer is implemented. This configuration supports rapid, stable charge–discharge cycles at a high current density of 20 mA cm⁻2. The large‐area stacked bipolar structure pouch cells, exceeding 36 cm2, achieve a discharge capacity of up to 2500 mAh, maintaining high cycle stability through discharge–charge cycles with 200 mAh per cycle. This approach significantly enhances the scalability, manufacturability, and production potential of ultrahigh‐capacity wearable ZABs, making them practical for widespread application in various portable and flexible devices.

Enhanced Methanol Electrooxidation and Supercapacitive Performance via Compositional Engineering of Colloidal Ni-Co Alloying Nanoparticles.

Among renewable energy technologies, particular attention is paid to electrochemically transforming methanol into valuable formate and storing energy into supercapacitors. In this study, we detailed a simple colloidal-based protocol for synthesizing a series of alloy nanoparticles with tuned Ni/Co atomic ratios, thereby optimizing their electrochemical performance. With the addition of 1 M methanol in 1 M KOH, the optimized composition was able to electrochemically produce formate at 0.149 mmol cm-2 h-1 with a Faradaic efficiency up to 95.1% at 0.6 V versus Hg/HgO within a 22-hour testing period. In 1 M KOH solution without methanol, the supercapacitive performance was achieved at a specific capacitance of over 1500 F g-1, and outstanding cycling stability with only approximately 20% decay after continuous 10000 charging-discharging cycles. These results underscore that the prepared Ni-Co alloy nanoparticles serve as multi-functional electrodes for electrochemical energy conversion and storage, particularly in the MOR and supercapacitors applications.

Investigation of Bi2MoO6/MXene nanostructured composites for photodegradation and advanced energy storage applications

This study presents nanostructured composite Bi2MoO6/MXene heterostructure by using hydrothermal method for photodegradation of the congo-red dye and also for energy storage devices. X-ray diffractometer (XRD), High Resolution Transmission Electron Microscopy (HRTEM), Field emission scanning electron microscope (FESEM) and X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET) were performed to examine the structural properties along with surface area and porosity of the material. Due to addition of MXene the larger surface area and improved pore size help to quickly break down additional organic pollutants by adsorbing them. The band gap of Bi2MoO6/MXene nanostructured composite reduced to 2.4 eV suggesting transfer of electrons from VB to CB. Bi2MoO6/MXene exhibits a high (92.3%) photocatalytic degradation rate for a duration of 16 min which was verified using UV-visible spectroscopy, also scavenger test was conducted to ascertain the reactive agent along with the degradation pathway was confirmed by LCMS. Elemental content was also established by using inductively coupled plasma mass spectrometry (ICP-MS). For estimating energy storage capacity cyclic voltammetry (CV) was performed. It was observed Bi2MoO6/MXene nanostructured composite electrodes had specific capacitance of 642.91Fg− 1, power density of 1.24 kWkg− 1, and energy density of 22.32 Whkg− 1 at a current density of 5Ag− 1 also it exhibited 64.42% capacity retention having current density 20 Ag− 1 throughout 10,000 Galvanostatic charge discharge (GCD) cycles. High electrical conductivity of Bi2MoO6/MXene electrode was again examined by Electrochemical impedance spectroscopy (EIS). These findings demonstrate the potential of Bi2MoO6/MXene nanostructured composites in both photodegradation and energy storage applications.

Long‐Term Estimation of SoH Using Cascaded LSTM‐RNN for Lithium Batteries Subjected to Aging and Accelerated Degradation

ABSTRACTAccurate estimation of state of health (SoH) of the battery over long‐term is a critical challenge for the battery management systems in electric vehicles. This is due to the challenges in accurately modeling the accelerated aging and degradation phenomena caused by diverse operating conditions of the battery. This paper presents a cascaded recurrent neural networks (RNN) with long short‐term memory (LSTM) to estimate the internal resistance and SoH, taking account of various abnormal operating conditions of the battery. A datasheet‐based degradation model of the battery is developed using fade equations. The training and validation data set for LSTM‐RNN are generated by subjecting the battery model to various factors that cause accelerated degradation, such as fast charging, varying operating temperatures, overutilization, and cell imbalance. The cascaded LSTM‐RNN is trained to estimate SoH only once after the completion of every charge–discharge cycle. The training error index parameters of the proposed SoH estimator are well within 1%, demonstrating the reliability and robustness of the estimator to diverse operating conditions of the battery.

Additive effect of Li on electrical property of ZnO passivation layer to control dendritic growth of Zn during recharge processes

This study investigates the effect of Li+ on the dendritic growth of Zn anodes in the presence of a ZnO passivation layer formed after discharge, with particular attention to the initial recharge process. 0.1 mol dm−3 Li+ effectively suppresses dendrites, while 2 mol dm−3 Li+ addition facilitates the same. The difference in Zn dendrite formation behavior is also indicated by the attenuation tendency of the potential oscillation accompanied by hydrogen evolution reaction during recharge. This is attributed to Li+ concentration dependence of the properties of the ZnO passivation layer formed during Zn anode discharge. Li+ modulates the carrier density of ZnO by altering its crystalline defect characteristics; the carrier density of ZnO with 0.1 mol dm−3 Li+ addition becomes approximately three times as high as that without additive owing to the oxygen vacancies and interstitial zinc that form additional donor level. By contrast, 2 mol dm−3 Li+ reduces the carrier density of ZnO by inducing zinc vacancies to form acceptor levels. The highly conductive ZnO produced by adding 0.1 mol dm−3 Li+ improves the reaction uniformity during recharge, which suppresses dendrite formation. This study provides valuable insight into the mechanisms and control strategies of Zn dendrite growth during the charge-discharge cycling of alkaline Zn rechargeable batteries.

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.

NiO/MnO2 coated on carbon felt as an electrode material for supercapacitor applications

Transition metal oxides have demonstrated excellent capability for charge storage when used in supercapacitor electrodes. This study undertook the hydrothermal synthesis of bimetallic nickel and manganese oxide (NiO/MnO2) on a carbon-felt (CF) substrate. NiO/MnO2/CF electrode was characterized and examined in a three-electrode system in a potassium hydroxide electrolyte. Cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic charge-discharge analyses revealed Faradaic behavior during charge storage, a specific capacity of 1627 F g-1, and a stability of 96.8% after 5000 consecutive charge-discharge cycles. Subsequent investigations were conducted in a two-electrode system for constructing a symmetrical supercapacitor using the NiO/MnO2/CF electrode. The energy and power densities were determined as 43Wh kg-1and 559 W kg-1. Additionally, the stability of the constructed supercapacitor device was examined over 5000 consecutive cycles, verifying a 92% stability through charge-discharge cycles. Finally, the fabricated supercapacitor was utilized to power an LED lamp, successfully maintaining the illumination for 53 s.