Galvanostatic Charge Discharge Research Articles

Electrochemical measurements, structural and morphological studies of electrodeposited polypyrrole supercapacitor electrode

This study presented the electrochemical deposition of potassium nitrate-doped polypyrrole (Ppy:KNO3) on stainless steel (SS), graphite sheet (GRs), and carbon fiber (CF) substrates, Ppy:KNO3/SS, Ppy:KNO3/GRs, and Ppy:KNO3/CF supercapacitor electrodes. Structural, morphological, and molecular analyses were conducted using X-ray diffraction (XRD), scanning electronic microscope (SEM), and Fourier transform infrared spectroscopy (FTIR). SEM images exhibited distinct morphologies of Ppy:KNO3 films, varying with cycles, scan rates, and Ppy:KNO3 concentrations. Ppy:KNO3/CF film displayed a unique structure with minimal particle aggregation. Electrochemical performance was assessed through Cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) measurements and electrochemical impedance spectroscopy (EIS). Notably, Ppy:KNO3/CF demonstrated a specific capacitance of 1020 F/g at 1 A/g. It exhibited 92 % capacitance retention after 1000 cycles, along with impressive power and energy densities of 310 W/kg and 71.2 Wh/kg, respectively. These results represented a significant progress in the development of high-performance, durable supercapacitors.

High-performance porous activated carbon derived from Acacia catechu bark as nanoarchitectonics material for supercapacitor applications

BackgroundThe increasing energy demands stemming from the extensive utilization of portable electronic devices are creating a huge energy deficit between demand and supply. In this scenario, it is not only sufficient to pursue and innovate the new renewable energy sources but also requires an ideal device for energy storage and conversion. MethodsIn this work, activated carbon (AC) was prepared from matured bark of Acacia catechu through a series of steps; pre-carbonization, carbonization, and activation. The AC was synthesized at different temperatures (400–800 °C) under inert atmosphere, using orthophosphoric acid as an activator. As-prepared sample (ACBH) was characterized by well-known characterization techniques. Energy storage capability was assessed in terms of Cyclic voltammetry, Galvanostatic charge-discharge, Electrochemical impedance, and Cyclic stability by three-electrode setup. Significant findingsThe ACBH-8 sample demonstrated superior electrochemical performance compared to other samples. The sample ACBH-8, as Negatrode, exhibited a specific capacitance of 282.4 F g−1 at 0.5 A g−1 and retained 95.4 % cyclic stability under 10,000 cycles. The excellent energy storage performance by green-class negatrode materials from the bio-waste substance empowers commercial applications.

Unveiling the Mn3+/ Mn4+ and Ni2+ potential as a high-capacity material for next-generation energy storage devices

In this study, we synthesized MnOx nanowires via hydrothermal methods and explored the impact of nickel (Ni) doping on their morphology and electrochemical properties. We investigated the structural and chemical changes induced by Ni incorporation by utilizing TEM and XPS analyses. Our results revealed that Ni doping influenced the distribution of manganese oxidation states, with 1.6 wt% Ni-doped nanowires exhibiting the optimized condition. Also, we observed a balance between the Mn3+/Mn4+ ratio with the Ni doping. Electrochemical characterization demonstrated enhanced capacity in Ni-MnOx nanowires at the 1.6 wt% Ni doping level. Galvanostatic charge-discharge measurements confirmed the superior performance of this level of Ni doping; moreover, the fabrication of asymmetric supercapacitor cells using these nanowires showed improved energy storage capabilities. The main results showed exceptionally high capacity (955.55 and 383.33 mAh g−1 at 1 and 20 A g−1, respectively) and an excellent rate capability. Cycling stability tests over 8500 cycles demonstrated excellent retention of capacity, underscoring the durability of the optimized Ni-MnOx nanowires, with a retention of 85 % of its initial capacity. Thus, this study emphasizes the significance of Ni doping in MnOx nanowires for enhancing electrochemical performance when the synthetic process is controlled, offering valuable insights for high-performance energy storage device development.

Asymmetric lithium supercapacitors with solid-state hybrid electrolytes containing zeolite particle and water-soluble polymer

Here we demonstrate that high-performance solid-state hybrid electrolytes are prepared via environment-friendly water-based processes of zeolite Y (Zy) particle, branched-poly(ethylene imine) (bPEI), and lithium hydroxide (LiOH). The hybrid Zy:bPEI:LiOH electrolytes (ZyPL) were successfully applied to fabricate asymmetric-type lithium supercapacitors consisting of graphite-based active electrodes and indium-tin-oxide (ITO) counter electrodes. Results showed that the ion conductivity of electrolytes was greatly dependent on the Zy content and reached the highest value (ca. 0.28 mS/cm) at Zy = 30 wt% due to the formation of interfacial ion transport channels between Zy particles and bPEI chains. The galvanostatic charging/discharging (GCD) test revealed that the ZyPL supercapacitors could deliver the highest potential of 2.28 V at Zy = 30 wt% compared to 1.86 V at Zy = 0 wt%. In particular, the ZyPL supercapacitors, after charging at 0.1 mA/g, exhibited a long-lasting high-potential level of > 1.0 V at Zy = 30 wt% compared to 0.5 V at Zy = 0 wt%. The long-term GCD cycle test disclosed that the ZyPL supercapacitors could work stably with a capacitance retention of 91.7 % even after 3000 cycles. The series connection of six ZyPL supercapacitors delivered ca. 10.94 V with consistent charging/discharging characteristics.

ULPING-Based Titanium Oxide as a New Cathode Material for Zn-Ion Batteries

The need for alternative energy storage options beyond lithium-ion batteries is critical due to their high costs, resource scarcity, and environmental concerns. Zinc-ion batteries offer a promising solution, given zinc’s abundance, cost effectiveness, and safety, particularly its compatibility with non-flammable aqueous electrolytes. In this study, the potential of laser-ablation-based titanium oxide as a novel cathode material for zinc-ion batteries was investigated. The ultra-short laser pulses for in situ nanostructure generation (ULPING) technique was employed to generate nanostructured titanium oxide. This laser ablation process produced highly porous nanostructures, enhancing the electrochemical performance of the electrodes. Zinc and titanium oxide samples were evaluated using two-electrode and three-electrode setups, with cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and galvanostatic charge–discharge (GCD) techniques. Optimal cathode materials were identified in the Ti-5W (laser ablated twice) and Ti-10W (laser ablated ten times) samples, which demonstrated excellent charge capacity and energy density. The Ti-10W sample exhibited superior long-term performance due to its highly porous nanostructures, improving ion diffusion and electron transport. The potential of laser-ablated titanium oxide as a high-performance cathode material for zinc-ion batteries was highlighted, emphasizing the importance of further research to optimize laser parameters and enhance the stability and scalability of these electrodes.

Reversible storage of tetraethyl ammonium cation in CFx-based cathode

Carbon fluorides (CFx) are considered as the potential cation storage materials in alkali metal-based battery systems because of the high theoretical specific capacity (865 mAh g-1 when x = 1). However, the reversibility of cathode reaction is seriously disturbed by the strong metal-fluorine interactions among the electrode products (e.g., LiF). By contrast, the relatively weak N-F bond makes the CFx-based battery system using quaternary ammonium cation (QAA+) a promising alternate, but the electrode mechanism between CFx and QAA+is little understood yet. In this work, tetraethylammonium cation (TEA+) is employed as the charge carrier using the electrolyte solution of sulfolane (SL) for CFx cathode. The CF0.56 electrode exports 710 mAh g-1 during the initial TEA+-CF reaction, and the electrode product (TEAF) can be decomposed under elevated potential that yields amorphous carbon fluoride and a reversible capacity of ∼300 mAh g-1 can be reached in the subsequent galvanostatic charge-discharge cycles. The TEAF product is non-crystallizable that exists in a sticky form on the surface of electrode, which contributes to an improved electrode structural stability while also leads to an unsatisfactory performance of the amorphous carbon fluoride with large number of superficial active sites. The electrode mechanism and the mechanical property of electrode interface are discussed in depth by in-situ Raman and electrochemical quartz crystal microbalance (EQCM) methods.

Waste Bakelite Board Derived Activated Carbon for Supercapacitor Electrode

The low biodegradability of Bakelite waste raises concerns for the environment as it is typically dumped in landfills. Herein we present regenerated activated carbon (AC) prepared from waste Bakelite board. Preparation of the ACs involves carbonization and KOH activation. Afterwards, the as-made AC were doped with N urea and subsequently pyrolyzed at high temperature. The resulting AC, with and without N-doping have been evaluated in supercapacitor. We demonstrate an N-doped AC that exhibits a specific capacitance (Csp) as high as 203.0 F g−1 at 0.5 A g−1 and retains 93.1% of the Csp after 5000 galvanostatic charge discharge (GCD) cycles at 3 A g−1. We also show that a symmetric supercapacitor exhibits a maximum energy density of 10.3 Wh kg−1 at 250 W kg−1. In general, our work shows a cost-effective approach towards high-performance waste-regenerated ACs.

The Influence of 3D Printing Methods and Materials on the Response of Printed Symmetric Carbon Supercapacitors

We compare the electrochemical response and intrinsic limitations of symmetric carbon-based supercapacitors using two 3D-printing techniques, vat polymerization (Vat-P) and fused deposition modelling (FDM). Two cell types were made in this study, one with metallized Vat-P-printed current collectors, the other with PLA (polylactic acid) FDM-printed current collectors in a similarly designed printed coin cell. Carbon-based electrode slurry (various combinations of SWCNT, GNP, Super-P, PVDF) and aqueous 6 M KOH electrolyte were used in these cells. We demonstrate the influence of internal resistance of each 3D-printing method by direct comparison of cyclic voltammetry and galvanostatic charge-discharge tests. The metallized conductive Vat-P cells display better conductivity and more ideal rectangular cyclic voltammetry response but suffer from poor cycle life in initial experiments (∼5,000 charge-discharge cycles before losing all specific capacitance). The FDM current collector cells using graphite-containing PLA materials have poorer conductivity, less ideal cyclic voltammetry curves, and are structurally less robust and partially porous, but offer very stable cycle life for supercapacitor cells retaining most of their specific capacitance after 100,000 charge-discharge cycles. The cycle life of the metallized Vat-P cells are improved by reducing the voltage window to 0.2–0.7 V to limit metal delamination and using Super-P and PVDF additives.

Efficacy of Capacitive Deionization Flow Cell Fabricated with Carbon Nanomaterial Modified Electrodes

The supply of freshwater is becoming a serious global challenge. Capacitive deionization (CDI) has been recognized as apromising and smart desalination technique to solve it. Carbonaceous materials, due to their non-toxic characteristics, areused for filtration, adsorption, and water deionization. In this study, a newly designed, homemade low CDI system wasfabricated, and carbon as electrode material was prepared from waste leather through a one-step activated pyrolysis process. Carbonaceous materials prepared at different temperatures were characterized by Fourier-transform infrared (FTIR), scanning electron microscopy (SEM), and X-ray diffraction (XRD) techniques. The charge storage capacity of the carbon materials casted on a glassy carbon electrode was evaluated using cyclic voltammetric and galvanostatic chargingdischarging techniques. The fabricated CDI system could be successfully used for the study of the removal capacity of NaCl from an aqueous solution. The removal capacity of carbon prepared at 600 °C from leather is 11.58 mgg1, which is about three times higher than commercial activated carbon at flow rate and applied potential of 23 mL min–1 and 1.0 V, respectively. Dhaka Univ. J. Sci. 72(2): 52-60, 2024 (July)

Fabrication and Electrochemical Evaluation of Cobalt Sulfide for Energy Storage Application

This work significantly contributes to this field by focusing on the synthesis and application of cobalt sulfide (CoS) as an innovative electrode material. Utilizing a straightforward hydrothermal process, we successfully synthesized CoS, emphasizing the optimization of reaction conditions. This included a detailed exploration of different solvents, primarily water and ethanol, to determine their impact on the final product. A comprehensive characterization of these parameters was conducted, shedding light on their crucial role in the material’s performance. The electrochemical attributes of the CoS electrodes were tested using cyclic voltammetry and galvanostatic charge discharge techniques. These investigations revealed that the CoS variant labeled as CoS_1 and CoS_2 demonstrated improved electrochemical properties. CoS_2 exhibited a specific capacitance of 360.0 Fg−1 at current load of 1.0 A/g. This superior performance of CoS_2 is largely attributed to its unique structural properties. The porous nature of CoS_2, coupled with its high surface area, plays a crucial role in enhancing its electrochemical capabilities. Furthermore, the material displayed impressive cyclic stability, maintaining up to 82.0% of its original capacitance. This level of durability highlights its suitability for long-term applications in energy storage devices. When tested in a three-electrode assembly, both CoS_1 and CoS_2 electrodes exhibited promising results. However, the distinct advantages of CoS_2, particularly in terms of capacitance and stability, underscore its potential as a superior candidate for energy storage applications.

Evaluating a Fe-Based Metallic Glass Powder as a Novel Negative Electrode Material for Applications in Ni-MH Batteries

Metallic glasses (MGs) are a type of multicomponent non-crystalline metallic alloys obtained by rapid cooling, which possess several physical, mechanical, and chemical advantages against their crystalline counterparts. In this work, an Fe-based MG is explored as a hydrogen storage material, especially, due to the evidence in previous studies about the capability of some amorphous metals to store hydrogen. The evaluation of an Fe-based MG as a novel negative electrode material for nickel/metal hydride (Ni-MH) batteries was carried out through cyclic voltammetry and galvanostatic charge–discharge tests. A conventional LaNi5 electrode was also evaluated for comparative purposes. The electrochemical results obtained by cyclic voltammetry showed the formation of three peaks, which are associated with the formation of Fe oxides/oxyhydroxides and hydroxides. Cycling charge/discharge tests revealed activation of the MG electrode. The highest discharge capacity value was 173.88 mAh/g, but a decay in its capacity was observed after 25 cycles, contrary to the LaNi5, which presents an increment of the discharge capacity for all the current density values evaluated, reached its value maximum at 183 mAh/g. Characterization analyses performed by X-ray diffraction, Scanning Electron Microscopy and Raman Spectroscopy revealed the presence of corrosion products and porosity on the surface of the Fe-based MG electrodes. Overall, the Fe-based MG composition is potentially able to work as a negative electrode material, but degradation and little information about storage mechanisms means that it requires further investigation.

Wide electrochemical stability window of NaClO4 water-in-salt electrolyte elevates the supercapacitive performance of poly(3,4-ethylenedioxythiophene)

Water-in-salt electrolytes (WiSEs) have emerged as the primary preference in the domain of aqueous-based supercapacitors, thanks to their wide electrochemical stability window (ESW > 1.23 V). Here, we have chemically synthesized a unique lettuce coral-like structure of tosylate doped-poly(3,4-ethylenedioxythiophene) (PEDOT-tos) and tested it for supercapacitor application in a 17 molal (m) NaClO4 WiSE, achieving an ESW of 1.9 V. The energy and power densities (Ed and Pd) of our PEDOT-tos supercapacitor are as high as 14 Wh kg-1 and 7210 W kg-1, respectively, with over 80 % capacitance retention after 10,000 continuous Galvanostatic charge-discharge cycles. The NaClO4 WiSE increases the Ed and Pd of PEDOT by several folds compared to traditional H2SO4 electrolyte. This work encourages the exploration of a suitable combination of a PEDOT-based composite material and WiSE for high-performance supercapacitors.

Investigation of a novel Defatted Spent Coffee Ground (DSCG)-supported Ni catalyst for fuel cell and supercapacitor applications

With the increase in energy demand, a material that can be used in fuel cell applications has been developed for both energy storage and the use of alternative energy sources to fossil fuels. In this study, a new Defatted Spent Coffee Ground (DSCG)-based electrode material was synthesized for two different application areas. A new electrocatalyst synthesis was carried out by subjecting DSCG to chemical activation and carbonization processes. The glycerol electrooxidation performances of the catalysts synthesized at 10–50 % Ni loading rates were investigated by CV measurements. 30 % Ni-DSCG catalyst exhibited the highest catalytic activity with 3.290 mA/cm2.As a result of the electrochemical measurements, 30 % Ni-DSCG catalyst with the best catalytic performance was used as the supercapacitor electrode material. The electrochemical performances of the produced supercapacitor electrodes were tested at room temperature using galvanostatic charge-discharge (GCD), Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques, and the capacity and stability of the electrodes were calculated as a result of the findings. In the calculations, the energy and power density of the 30 % Ni-DSCG supercapacitor electrode were calculated as 22.897 Wh kg−1, 841.114 W kg−1, respectively. The supercapacitor electrode capacitance was found to be 50.48 F/g.Its cyclic capacity was found to be 90 %. It showed that the DSCG-based synthesized electrocatalyst could be a good option for energy storage technology as EDLC electrode material and fuel cell applications as anode catalyst due to its good conductivity, superior cyclic stability, environmental friendliness and low cost.

Probing the performance of Co-precipitated Co3(PO4)2@W3(PO4)4/GO electrodes for supercapacitor application

A critical first step in realizing high-performance supercapacitors is the growth of functional electrodes that are inexpensive, stable, and extremely active. To create a variety of electrodes, we present here an inventive approach to fabricating an ordered microporous Co3(PO4)2@W3(PO4)4/GO composites electrode on a nickel foam (NF) substrate that was first created via co-precipitation techniques for nanoparticles and then drop casting method for fabrication of these electrodes. The Co3(PO4)2@W3(PO4)4/GO composite electrodes show good electrochemical activity in three electrode configurations, thanks to its abundant active sites, and high specific surface area provided by graphene oxide (GO) structured microporous structure that facilitates the charge/mass transfer processes. Additionally, Co3(PO4)2@W3(PO4)4/GO composite electrodes are rightly employed as binder-free electrodes for supercapacitor applications, providing excellent specific capacitances, energy and power densities as well as good electrochemical firmness. The Co3(PO4)2@W3(PO4)4/GO electrode exhibits excellent performance, delivering a high specific capacitance of 1230 F/g from cyclic voltammetry (CV), 1420 F/g from galvanostatic charge-discharge (GCD) and long-term cycling stability of over 74.7 % after 10, 000 complete cycles.

Ligand-engineered Fe(II)-metallo-supramolecular polymer with benzothiadiazole: Boosting electrochromic energy storage efficiency

The development of intelligent electrochromic energy storage devices that visually display color changes to indicate their charging and discharging status while offering high energy and power densities is gaining interest as a renewable energy solution. Our research engineered a bisterpyridine ligand (BTZ) with a benzothiadiazole spacer and its metallo-supramolecular polymer (Fe-BTZ) via Suzuki coupling and complexation reactions. Spectroscopic, morphological, and structural characterizations revealed nano-rod morphology due to higher aggregation of 1D Fe-BTZ metallo-supramolecular polymer. Quasi-solid-state electrochromic devices with Fe-BTZ as the active layer exhibited significant color changes (matte purple to dirty yellow), an optical contrast of 65.2 % at 567 nm, high coloration efficiency (518.2 cm2/C), quick coloration (0.5 s) and bleaching (1.8 s), and exceptional electrochromic durability compared with commonly used Poly-Fe metallo-supramolecular polymer. Conjugated ridged benzothiadiazole spacers enhanced electron mobility between the Fe-center during electrochemical transitions, increasing coloration efficiency, durability, and electrochromic speed. The Fe-BTZ and Prussian blue (PB)-based quasi-solid-state energy storage device also showed fast response times (1.1 s and 1.9 s), high CE (1077 cm2/C), 6500-cycle durability, high volumetric capacitance (70.1 ± 4 F/cm3) with a specific capacity of 10.96 mAh/g at 0.14 A/g current density and 74 % capacitance retention over 20,000 galvanostatic charge–discharge cycles. The device’s ability to power 18 red LEDs demonstrates its practical applicability.

Enhanced electrochemical performances of ternary polypyrrole/MXene/Gum arabic composites as supercapacitors electrode materials

The development of supercapacitor electrodes for high energy storage applications requires the use of ternary composites made of PPy, Mxene, Gum Arabic (PPy/Mxene/GA) these materials are special because they have new characteristics like cyclic stability, and high specific capacitance. The pure PPy, PPy/Mxene and PPy/Mxene/Gum Arabic show the shifting and appearance of new peaks in UV-Visible spectra, which are further supported by the Fourier transform infrared spectroscopy (FT-IR). The appearance of new peaks in X-ray diffraction (XRD) of PPy confirms presence of Mxene and Gum Arabic, which is in agreement with the energy dispersive X-ray (EDX) analysis. The electrochemical techniques such as Cyclic Voltammetry (CV), Galvanostatic Charge Discharge (GCD) and Electrochemical Impedance Spectroscopy (EIS) show that the (PPy/Mxene/GA) ternary composite maintains 94 % of the specific capacitance retention after 2000 cycles and; reaches a maximum specific capacitance of 657.64 F/g at 1 A/g. As compared to Pure PPy and PPy/Mxene composite the PPy/Mxene/GA composite show small intrinsic resistance Rs and charge transfer Rct values 0.11Ω and 6.15Ω respectively. The outstanding electrochemical properties of PPy/Mxene/GA composite are ascribed to the blending of three different type compounds PPy, Mxene and GA and theirs mutual beneficial effects. These findings show that ternary composite material holds great promise for use in these condition involving portable electronic storage devices.

Zn-doped V2O5 film electrodes as cathode materials for high-performance thin-film zinc-ion batteries

Zn-doped V2O5 film electrodes were prepared by in-situ growth on indium‑tin oxide (ITO) conductive glass by a low-temperature liquid-phase deposition method and calcined by calcination treatment, and assembled into thin-film zinc-ion batteries (ZIBs). After galvanostatic charge/discharge (GCD) tests with 90 and 200 charge/discharge cycles, the ZIBs system provided specific capacities of 95.7 mAh m−2 and 63.9 mAh m−2 with capacity retention rates of 97.88% and 78.72%, respectively. The electrochemical reaction process of the Zn-doped V2O5 film electrode was analyzed by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) to understand the insertion/extraction mechanism of Zn2+. The doping of appropriate amount of Zn2+ in the preparation plays the role of “pillar”, which helps to stabilize the structure of V2O5 and improve the cycling stability and lifetime. Therefore, the research may provide a new idea for the assembly and preparation of thin-film ZIBs with improved performance.

Controlled synthesis and electrochemical characterization of Co3V2O8 hexagonal sheets for energy storage applications

This work explores the hydrothermal synthesis of Co3V2O8 hexagonal sheets and their effects on the structure and electrochemical properties of the electrode material, with a focus on various urea concentrations. The prepared materials were extensively characterized through a variety of imaging and electrical techniques, such as asymmetric supercapacitor studies, cyclic voltammetry (CV), Galvanostatic charge-discharge (GCD) analysis, electrochemical impedance spectroscopy (EIS), and X-ray photoelectron spectroscopy (XPS). Morphological analyses revealed that distinct hexagonal sheets formed based on the urea content. XPS analysis has provided information about the oxidation states and chemical composition of the produced materials. The high capacitance of 293 F/g with an energy density of 14.68 Wh/kg at an applied current density of 1 mA/cm2 over CVO-0.6MU sample demonstrates the electrochemical capabilities of hexagonal sheets of Co3V2O8 as electrode materials for supercapacitor, as demonstrated by electrochemistry research such as GCD, CV, and EIS. Furthermore, we were able to attain a high capacitive retention of approximately 99 % columbic efficiency up to 20,000 cycles, as well as a high power density exceeding CVO-0.6MU, or 142 W/kg. These findings showed how highly feasible our as-synthesized CVO-0.6MU electrode material is as an energy storage device. The research carried out on asymmetric supercapacitor provides more evidence of the stable and promising capacitive performance of the synthetic materials, Additionally effect of the temperature on ASC were studied. This extensive work offers crucial details regarding the electrochemical characteristics and regulated manufacture of Co3V2O8 hexagonal sheets, which may find application in future cutting-edge energy storage technologies.

Improving Lithium-Ion Battery Performance: Nano Al2O3 Coatings on High-Mass Loading LiFePO4 Cathodes via Atomic Layer Deposition

Lithium iron phosphate (LiFePO4 or LFP) is a promising cathode material for lithium-ion batteries (LIBs), but side reactions between the electrolyte and the LFP electrode can degrade battery performance. This study introduces an innovative coating strategy, using atomic layer deposition (ALD) to apply a thin (5 nm and 10 nm) Al2O3 layer onto high-mass loading LFP electrodes. Galvanostatic charge–discharge cycling and electrochemical impedance spectroscopy (EIS) were used to assess the electrochemical performance of coated and uncoated LFP electrodes. The results show that Al2O3 coatings enhance the cycling performance at room temperature (RT) and 40 °C by suppressing side reactions and stabilizing the cathode–electrolyte interface (CEI). The coated LFP retained 67% of its capacity after 100 cycles at 1C and RT, compared to 57% for the uncoated sample. Post-mortem analyses, including scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS), were conducted to investigate the mechanisms behind the improved performance. These analyses reveal that Al2O3 coatings are highly effective in reducing LFP electrode degradation during cycling, demonstrating the potential of ALD Al2O3 coatings to enhance the durability and performance of LFP electrodes in LIBs.

Incorporating Ag into Nd-Succinate MOF: Tunned electrochemical supercapacitor behaviour of Ag modified Nd-Succinate and electrochemical reaction mechanism

The electrode materials must be tailored to achieve higher energy and power densities and thus improve the supercapacitor's performance. This study explores the impact of incorporating Silver (Ag) into a Neodymium-Succinate Metal Organic Framework (Nd-Succinate) on supercapacitor behaviour. Initially, the Nd-Succinate MOF was characterized by structural, morphological, and spectroscopic characterizations. Subsequently, Ag/Nd-Succinate was synthesized and characterized. The electrochemical performance of Ag/Nd-Succinate was evaluated in a 6 M KOH electrolyte; the results indicated a significant enhancement in supercapacitor performance upon incorporating Ag into parent Nd-Succinate. From galvanostatic Charge-Discharge cycles (GCD), the capacitance for Ag/Nd-Succinate was determined to be 1389 F/g, i.e., 42 % higher than that of bare Nd-Succinate which was measured at 978 F/g. at a current density of 1.25 A/g. Ag/Nd-Succinate showcased an 89 % retention value for multiple retention cycles, slightly higher than the retention value obtained (84 %) for Nd-Succinate. The results of electrochemical experiments (Cyclic voltammetry (CV) and Electrochemical Impedance Spectra (EIS)) provided information about the nature of electron transfer and capacitance enhancement upon the introduction of Ag into Nd-Succinate. These findings provide valuable information on modifying MOFs and introducing metal that will help produce high-performance supercapacitor electrodes.