Electrodes For Energy Storage Applications Research Articles

Porous Single-Crystal Nitrides for Enhanced Pseudocapacitance and Stability in Energy Storage Applications.

Supercapacitors have emerged as a prominent area of research in energy storage technology, primarily because of their high power density and notable stability compared to batteries. However, their practical implementation is hindered by their low energy densities and insufficient long-term stability. In this study, bulk porous Nb4N5 and Ta3N5 single crystals with excellent pseudocapacitance and electrical conductivity are successfully prepared by solid-phase transformation method. These monolithic porous single crystals (PSC) exhibit a long-range ordered crystalline architecture and substantial specific surface area, which facilitate rapid charge transport and ion diffusion within the electrolyte-permeated crystal lattice. Notably, the areal capacitance of the porous Nb4N5 single crystals is 12.9 F cm-2 at a current density of 6mA cm-2 and 35.08 F cm-2 at a scan rate of 1mV s-1. Furthermore, the energy density reached 1.79 mWh cm-2 at a power density of 20mW cm-2, demonstrating their high energy storage capability. Moreover, these porous Nb4N5 single crystals exhibited robust capacitance retention and exceptional cycling stability, making them promising candidates for use as electrodes in energy storage applications. These results underscore the significant potential of porous metal nitride single crystals in advancing the field of capacitive energy storage.

Biobased N-Doped Primary and Secondary Char Electrodes for Energy Storage Application Using Pyrrole as the N Precursor

Biobased N-Doped Primary and Secondary Char Electrodes for Energy Storage Application Using Pyrrole as the N Precursor

Improved electrochemical performance of Fe3O4/TiO2 composite thin film electrode for energy storage applications

This study is the first attempt to examine the electrochemical properties of TiO2 composite with Fe3O4 thin film. In our analysis, X-Ray diffraction (XRD) confirms the formation of Fe3O4 on TiO2. Fourier Transform Infrared Spectroscopy (FT-IR) and Raman spectroscopy confirmed the functional groups. The UV–Vis spectroscopy analysis shows that the addition of Fe3O4 results in decrease in optical band gap. Our Cyclic Voltammetry (CV) results demonstrate that, under steady state conditions, the behaviors of TiO2 and Fe3O4/TiO2 electrodes regarding ion adsorption and charge transmission vary. Pseudocapacitive effects and charge transfer affects the functionality of the TiO2 electrode, whereas two-layer capacitance effects primarily control the response of the Fe3O4/TiO2 electrode. Numerous factors, including ion diffusion, rate capability, charge transfer, and series resistance, can be directly determined using electrochemical impedance spectroscopy (EIS). The experimental results and analysis presented in this work brings to light the significance of Fe3O4 in the electrochemical response of an electrode-electrolyte interface.

In-situ synthesis of synergistic ZnMn2O4/MnOOH nanocomposite as a cutting-edge pseudocapacitive electrode material for all-solid-state asymmetric supercapacitors

Currently, there has been a growing interest in constructing metal oxide composite structures through the in-situ synthesis method, especially for fabricating electrode materials for supercapacitors. This approach offers several advantages, such as improved contact between different materials, enhanced conductivity, efficient ion diffusion, and better overall electrochemical performance. This work investigates the synthesis of zinc manganese oxide and manganese oxyhydroxide (ZnMn2O4/MnOOH) composite using a solvothermal method. The structure, surface morphology, and composition of the ZnMn2O4/MnOOH composite were elucidated using standard physicochemical characterization techniques where the presence of ZnMn2O4 and MnOOH phases was confirmed and the ZnMn2O4/MnOOH nanocomposite behaved as a pseudocapacitive electrode with a notable specific capacitance of 1039.2 F g⁻1 at a current density of 1 A g⁻1. When subjected to a 10-fold increase in current density, the ZnMn2O4/MnOOH electrode maintained 50 % of its initial capacity, registering 513.4 F g⁻1. Additionally, the electrode showcased excellent cyclic stability, preserving 95 % of its initial capacity after 5000 cycles at 10 A g⁻1. Moreover, the constructed ZnMn2O4/MnOOH//activated carbon (AC) asymmetric supercapacitor (ASC) device attained a high energy density of 29.45 Wh kg⁻1 at a power density of 1384.5 W kg⁻1. The results confirm that the ZnMn2O4/MnOOH composite, prepared in a single synthesis step, shows great potential as a phenomenal pseudocapacitive electrode for energy storage applications.

Sustainable organic electrodes using black soldier fly-derived melanin for zinc-ion hybrid capacitors

Pressing environmental challenges require focused research on sustainable solutions in the domains of energy, water, food, land, and climate. The pigment eumelanin has recently been positioned as a promising candidate for solving issues in health, sensors, and energy storage. However, the low solubility of eumelanin in aqueous solvents, difficult film processibility, and high cost have hindered the material from wide deployment. Here, we propose melanin extracted from the black soldier fly, Hermetia illucens (Mel-BSF), as a sustainable alternative for the preparation of organic electrodes in energy storage applications. Mel-BSF displays pseudocapacitive behaviour with a high potential window, good electrochemical stability, and higher maximum capacity (91.8 mAh g−1) compared to synthetic eumelanin (17.3 mAh g−1) as the working electrode material in zinc-ion hybrid capacitors using an ionic liquid electrolyte. Structural and surface investigations reveal that additional aliphatic compounds, potentially lipids present after Mel-BSF refinement, significantly increase the film stability and redox centre availability.

Bimetallic Sulfide Hollow Nanocubes Heterostructure Promotes Dual Coupling of Conversion and Alloying/Dealloying Reactions to Achieve Durable Potassium-Ion Battery Anode.

Conversion and alloying-type transitional metal sulfides have attracted significant interests as anodes for Potassium-ion batteries (PIBs) and Sodium-ion batteries (SIBs) due to their high theoretical capacities and low cost. However, the poor conductivity, structural pulverization, and high-volume expansions greatly limit the performance. Herein, Co1-xS/ZnS hollow nanocube-like heterostructure decorated on reduced graphene oxide (Co1-xS/ZnS@rGO) composite is fabricated through convenient hydrothermal and post-heat vulcanization techniques. This unique composite can provide a more stable conductive network and shorten the diffusion length of ions, which exhibits a remarkable initial charge capacity of 638.5mA h g-1 at 0.1 A g-1 for SIBs and 606mA h g-1 at 0.1 A g-1 for PIBs, respectively; It is worth noting that the composite presents remarkable long stable cycle performance in PIBs, which initially delivered 274mA h g-1 and sustained the charge capacity up to 245mA h g-1 at high current density of 1 A g-1 after 2000 cycles. A series of in situ/ex situ detections and first principle calculations further validate the high potassium ions adsorption ability of Co1-xS/ZnS anode materials with high diffusion kinetics. This work will accelerate the fundamental construction of bimetallic sulfide hollow nanocubes heterostructure electrodes for energy storage applications.

Unraveling cation intercalation mechanism in MXene for enhanced supercapacitor performance

MXenes are two-dimensional materials with high electrical conductivity, adjustable composition, and tunable surface terminations, holding promise for supercapacitors (SCs). However, the susceptibility to interlayer restacking and the attachment of inactive -F terminations reduce their capacitances and rate performance. To resolve these issues, electrochemistry-driven cation intercalation (ECI) followed by calcination is proposed to unclog the interlayers and modify surface chemistry simultaneously. It is found that Mn-modified Ti3C2Tz MXene exhibits exceptional volumetric capacitance (1655.5 F cm−3 at 1 mV s−1, 1.5 times higher than that of pristine Ti3C2Tz) and excellent rate performance (72.3 % retention from 1 A g−1 to 50 A g−1) due to the unblocked interlayers and the increased -O terminations. Density Functional Theory (DFT) results reveal that the intercalated Mn2+ displayed the largest formation energy difference, manifesting a great driving force to form active -O terminations, which is crucial for improving electrochemical performance. Kinetic analysis reveals that the intercalated Mn2+ increases the termination-related capacitances (pseudocapacitance and diffusion-controlled capacitance) significantly. Symmetric and asymmetric SCs demonstrate high energy densities at high powers, showing the advance of the Mn-intercalated Ti3C2Tz. The findings clarify how metal cation intercalation affects MXene performance, providing insights for designing MXene-based electrodes in energy storage applications.

Nanostructured N-doped Ti3C2/TiO2 composite for high-performance supercapacitor

Herein, the N-doped Ti3C2/TiO2 nanostructure has been synthesized via hydrothermal treatment and following annealing in NH3. TiO2 nanoparticles in-situ grow on the surface of Ti3C2 spontaneously, resulting in the stable electron transport between TiO2 and Ti3C2. Besides, Ti3C2 nanosheets as conductive substrates make up for the poor conductivity of TiO2. The doping of N in Ti3C2/TiO2 composite further improves the electrical conduction. The ultimate N-doped Ti3C2/TiO2 composite achieves a higher specific capacitance of 737.4 F g−1 than Ti3C2 (324.4 F g−1) at 0.5 A g−1. More importantly, the composite displays a high specific capacitance retention of 81 % over 12,000 cycles. Besides, the assembled symmetrical supercapacitor (SSC) manifests an excellent specific capacitance of 236.4 F g−1 at 1 A g−1 and a comparable energy density of 32.8 Wh kg−1 at the power density of 500 W kg−1. This work provides promising guidance for the fabrication of durable electrodes for energy storage application.

Insight into the mechanism of nitrogen doping in MXenes with controllable surface chemistry

Nitrogen doping emerges as a potent strategy to enhance the electrochemical attributes of two-dimensional MXene materials, recognized for their utility in energy storage solutions. Although advancements have been made, the specific roles of varied doping sites in modifying electrochemical behavior are not fully delineated. This investigation explores nitrogen-doping mechanisms in MXenes with tailored surface chemistries, utilizing a blend of experimental approaches and density functional theory calculations. The distinct roles of nitrogen dopant sites are explored, and the evolution of the electronic structure and stability of the material before and after nitrogen modifications via the urea hydrothermal method are also investigated. The synthesized N-V2CTx-160 MXene electrodes exhibit favorable surface characteristics for energy storage, achieving impressive capacitance properties with a gravimetric capacitance of 592.9 F/g at 2 mV/s in 1 M H2SO4 electrolyte. This work provides a valuable insight for the development of high-performance MXene electrodes for energy storage applications.

Carbon decorated Li-based orthosilicate electrode for energy storage application

Carbon decorated Li-based orthosilicate electrode for energy storage application

Ion beam irradiation induced modification of PPy/ZnO nanocomposite thin films for supercapacitor applications

Thin films of Polypyrrole/Zinc Oxide (PPy/ZnO) nanocomposite were fabricated using electrodeposition and subjected to 100 MeV Ag10+ ion beam irradiation at various fluences ranging from 1.0 × 1010 to 1.0 × 1012 ions cm-2. We characterized the well-synthesized PPy/ZnO nanocomposite thin films and examined the modification induced by irradiation using XRD, Raman, FTIR, FESEM-EDS, and AFM techniques. FESEM and AFM images reveal that PPy/ZnO exhibits a cauliflower-like nanosphere structure. An increase in roughness indicates a larger surface area of the electrode, which improves capacitive performance at 1.0 × 1010 ions cm-2, enhancing ion transport from the electrode surface to the bulk. The damage tracks formed by highly energetic ions along their path may contribute to more charge storage by increasing the roughness of the nanocomposite thin film electrodes for energy storage applications. We evaluated the electrochemical performance of thin films using CV, EIS, and GCD measurements. Electrochemical studies reveal enhanced capacitive properties up to 1.0 × 1010 ions cm-2 fluence and decrease at higher fluences. The irradiated nanocomposites achieve a higher specific capacitance of 323.11 F g-1, and the fabricated device shows cyclic stability of 86 %, a remarkable power density (P) of 0.72 kW kg-1, and an energy density (Ep) of 6.32 Wh kg-1.

Mesoporous Mn-substituted MnxZn1-xCo2O4 ternary spinel microspheres with enhanced electrochemical performance for supercapacitor applications.

Extensive investigations have been carried out on spinel mixed transition metal oxide-based materials for high-performance electrochemical energy storage applications. In this study, mesoporous Mn-substituted MnxZn1-xCo2O4 (ZMC) ternary oxide microspheres (x = 0, 0.3, 0.5, 0.7, and 1) were fabricated as electrode materials for supercapacitors through a facile coprecipitation method. Electron microscopy analysis revealed the formation of microspheres comprising interconnected aggregates of nanoparticles. Furthermore, the substitution of Mn into ZnCo2O4 significantly improved the surface area of the synthesized samples. The electrochemical test results demonstrate that the ZMC3 oxide microspheres with an optimal Mn substitution exhibited enhanced performance, displaying the largest specific capacitance of 589.9Fg-1 at 1Ag-1. Additionally, the ZMC3 electrode maintained a capacitance retention of 92.1% after 1000 cycles and exhibited a significant rate capability at a current density of 10Ag-1. This improved performance can be ascribed to the synergistic effects of multiple metals resulting from Mn substitution, along with an increase in the surface area, which tailors the redox behavior of ZnCo2O4 (ZC) and facilitates charge transfer. These findings indicate that the incorporation of Mn into mixed transition metal oxides holds promise as an effective strategy for designing high-performance electrodes for energy storage applications.

Biomass waste derived from cassia fistula into value-added porous carbon electrode for aqueous symmetric supercapacitors

Activated carbon derived from biomass sources has been renowned as one of the key materials and economical precursors for numerous energy conversion and storage applications. Herein, we utilized a less explored Cassia fistula (Pulp and seed) biomass as the carbon source for supercapacitor application. Further, a less toxic and low activation method has been implemented to activate the biomass-derived carbon. The highly dense seed resulted in better porous compared to the pulp source. The electrochemical performances of the bio-carbon electrodes have been examined by CV, GCD, and EIS studies. The activated carbon derived from the Cassia fistula seed (CFSA) electrode achieved a specific capacitance value of 136.5 Fg−1 at 0.5 Ag−1 in 3 M KOH. Moreover, the electrode demonstrates an extremely long stability by sustaining 98 % of initial capacitance after 10,000 cycles, which signifies the robust electrochemical stability behavior of the obtained electrode. Further, the aqueous symmetric supercapacitor achieved a maximum energy and power density of 7.2 WhKg−1 and 3488.1 WKg−1, respectively. Likewise, after 10,000 stability cycles, the cell retains 96.4 % capacitance at 5 Ag−1 which denotes the noteworthy capacitive behaviour of the CFSA electrode. Thus, the present work suggests an eco-friendly resource for developing an effectual carbon electrode for energy storage applications.

Development of cost-efficient BaMnO3/rGO nanocomposite as electrode for energy storage applications in supercapacitor

The excessive fossil fuels utilization leads to environment contamination along with energy loss and is becoming a serious issue in these days. Therefore, to handle these energy issues, alternative sources and energy-storing devices like supercapacitors are in demand in the modern era. Many perovskites have been used in supercapacitors as electrode material but because of its less cyclic stability and poor conductivity, rGO mixed to enhance the electrochemical properties of perovskite. Therefore, we used rGO with BaMnO3 to fabricate BaMnO3/rGO nanocomposite through hydrothermal method for supercapacitor electrodes. After different physical analyses, BaMnO3/rGO nanocomposite showed remarkable electrode applications having distinct nanostructure with increased surface area, conductivity, crystallinity and improved morphology. The electrode material demonstrated a substantial surface area (54.32 m2 g−1) measured by Brunner–Emmett–Teller analysis, while scanning electron microscopy results showed that BaMnO3 dispersed tightly on rGO. The fabricated electrode material demonstrated a specific capacitance of 1359.85 F g−1, energy density of 78.62 Wh kg−1 and power density of 322.6 W kg−1 at 1 A g−1 current density. Furthermore, the Nyquist plot revealed a low value of Rct (0.04 Ω), indicating good electrical conductivity, while the material displayed stability even after 5000th cycle. This work revealed that, such extraordinary and outstanding qualities of BaMnO3/rGO nanocomposite provide a viable option for use in next-generation supercapacitor applications along with high stability and cost effectiveness.

Polyaniline/TiO2 nanocomposite for high performance supercapacitor

A binary polyaniline/TiO2 and varied weight ratio TiO2/PANI nanocomposite was successfully fabricated as an electrode for energy storage application. The TiO2 nanoparticles were synthesized via manual irradiation system with wavelength 256 nm and power 125 W. Polyaniline/TiO2 was then prepared by in situ polymerizing TiO2 onto aniline monomer. Polyaniline nanofibers are loaded with TiO2 to product core-shell system. The polyaniline/TiO2 nanocomposite were characterized using XRD, XPS, TEM, TGA, CP and LCR measurements. The structure properties were examined by XRD and XPS, which confirmed preparing polyaniline/TiO2 binary nanocomposite. The thermal stability was investigated using TGA and obtained high stability of polyaniline/TiO2 compared with polyaniline, while the electrochemical properties were examined by LCR measurements. The LCR measurements were appeared dielectric constant and dielectric loss for incorporating TiO2 through PANI. Varied weights ratio TiO2 was worked in increasing the stored energy ability of polyaniline. Notably, the electrochemical investigate results appear that the PANI/TiO2 has a high specific capacitance (250 F/g) compared with pure PANI (200 F/g). KEY WORDS: Supercapacitor, UV irradiation, XPS, LCR, nanofibers Bull. Chem. Soc. Ethiop. 2024, 38(4), 1177-1188. DOI: https://dx.doi.org/10.4314/bcse.v38i4.28

A Comparative Study on the Influence of N‐Doped Primary and Secondary Hydrochars on the Electrochemical Performance of Biobased Carbon Electrodes for Energy Storage Application

AbstractThe hydrothermal carbonization (HTC) technique and subsequent pyrolysis were applied. Herein, two different types of biobased feedstocks, sucrose (Suc) and Miscanthus (Mis), were chosen. Urea served as N precursor for the in situ doping. HTC of Suc and Mis with urea leads to N‐doped hydrochars (N‐HCs). Suc and Mis decompose in different, complex degradation pathways, which leads to the emergence of N‐HCs consisting of distinct ratios of N‐containing primary chars (N‐PCs) and secondary chars (N‐SCs). After pyrolysis, maximum N contents of 5.6 wt % and 4.8 wt % of the N‐doped pyrolyzed hydrochar (N‐PHC) electrodes from Suc and Mis, respectively were reached. The role of PC and SC formation on the impact of N‐doping in the context of physicochemical properties of the N‐PHCs was compared with each other. In this study, they were tested with respect to the influence of N‐PCs and N‐SCs on their electrochemical performance in energy storage application. It turned out that the electrical conductivity (EC) and specific capacitances increased. Highest EC value of 129.1 S ⋅ cm−1 was obtained with N‐PHC based on Suc. Simultaneously, enhanced average specific capacitances of 47.0 F ⋅ g−1 at 5 mV ⋅ s−1 and 3.5 F ⋅ g−1 at 100 mV ⋅ s−1 are ascertained with N‐PHCs from Suc and Mis, respectively.

Engineering time-dependent MOF-based nickel boride 2D nanoarchitectures as a positive electrode for energy storage applications

It is of great importance to design rationally combined metal-organic frameworks (MOFs) with multifunctional nano geometries to develop advanced energy storage devices. We devised a simple room-temperature boronization system to produce ultrathin Ni-ZIF/Ni-B nanosheets with plenty of crystalline-amorphous phase barriers. The Ni-ZIF/Ni-B-24 h nanoflakes electrodes exhibited a specific capacitance of 104.2F g−1 with the cyclic stability of 94.5 % using the flaky architecture and inherent properties of the Ni-ZIF/Ni-B-24 h nanoflakes. Furthermore, an asymmetric supercapacitor made of Ni-ZIF/Ni-B-24 h and activated carbon had a high specific capacitance of 370.7F g−1 at 1 A/g, and the energy density of 131.8 W h kg−1 at a power density of 800 W kg−1. Intriguingly, Ni-ZIF/Ni-B-24 h nanoflakes have consistently delivered higher specific capacities because of the adequate electrochemical active sites and an increase in electron transfer rate during redox reactions.

Tailoring the graphene framework by embedding Nb2O5 and silver nanoparticles for electrodes in energy storage applications

In this study, Nb2O5/GNs and Ag/GNs-based nanocomposites were synthesized via a facile single-step hydrothermal approach. Using scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Raman spectroscopy, fourier-transform infrared (FTIR) spectroscopy, and UV–vis spectroscopy, the morphology, functional groups, structure, and optical and electrical properties of the as-prepared materials were examined. XPS studies show the predominant signal at 284.8 eV is attributed to the sp2 carbon atoms (C 1) that comprise graphitic areas, indicating that the majority of the C atoms are arranged in a honeycomb lattice. FTIR spectrum confirms bonding, such as CO, CH2, CO, CC, OH, AgO, and NbONb in the nanocomposite. Further, the specific capacitance (Csp) of the Nb2O5/GNs and Ag/GNs was calculated 603 Fg−1 and 810 Fg−1 at different current densities, The Nb2O5/GNs exhibit 109 Wh/kg and 2180 W/kg energy and power density, respectively. However, the Ag/GNs electrode exhibited an energy density of 145.8 Wh/kg and a power density of 3645 W/kg, with cyclic stability retentions of 93.06 % and 97.02 %, respectively. The capacitance retention finished at 1000 cycles. Moreover, the achieved resistance from the I–V characteristics curve shows enhanced electrical conductivity of synthesized nanocomposites. These results suggested that the materials can have bright future in next-generation energy storage devices.

Boosted electrochemical performance of flower-like carbon microspheres derived from polyimides containing hydroxyl groups for supercapacitor electrodes

Herein, the flower-like microspheres derived from polyimides containing hydroxyl groups are firstly synthesized through a solvothermal technique. Then, the corresponding flower-like carbon microspheres are obtained after high-temperature carbonization. The influences of the poly(amic acid) concentration, solvothermal temperature, and treatment time on the electrochemical behaviors of carbon microspheres are investigated. The optimized carbon sample PC-2-180-10 demonstrates a distinct micro/mesopore characteristic, leading to a specific capacitance of 254.4 F g−1 at 0.5 A g−1. Subsequently, the sample is chemically activated with HNO3 for improving its electrochemical performance. When the HNO3 concentration is optimized as 6 M, the treatment temperature and time are 75 °C and 30 h respectively, the activated carbon microspheres APC-6-75-30 exhibit a maximum specific capacitance of 387.6 F g−1. Moreover, the APC-6-75-30 is symmetrically fabricated into a button-type supercapacitor (SC) device, and the SC shows a specific capacitance of 88.5 F g−1, with an energy density of 11.81 Wh kg−1 at a power density of 240.1 W kg−1. Six months later, the SC still demonstrates a better capacitive performance. Optimizing the solvothermal parameters and HNO3 treatment conditions, this work presents an effective strategy for boosting the electrochemical performance of flower-like carbon microspheres as a promising electrode for energy storage applications.

In-situ electronic modulation of ultra-high-capacity S-modified Cu/Cu2O electrodes for energy storage applications

Due to the modification of anions, an electron redistribution occurs at the metal ions can affect the electronic structure, and induce excellent specific capacity. Herein, we report an effective and low time-consuming method by in-situ wet chemical reduction at room temperature to construct S-modified Cu/Cu2O negative electrode material. Moreover, the sulfur can occupy partial O sites in Cu2O to play a crucial role in the electronic structure of the material, demonstrated by DFT calculation, XRD, XPS and XAS measurements. The prepared S-Cu/Cu2O samples exhibit excellent electrochemical performance with high specific capacity of 669 mAh·g−1 at 1 A·g−1, even 450 mAh·g−1 at 10 A·g−1. When the materials are composed as pseudo capacity-type cathode//battery-like anode (MnO2//S-Cu/Cu2O), and (+) battery-type//battery-type (-) (Ni-Cu hydroxide/Cu(OH)2/CF//S-Cu/Cu2O) hybrid capacitors, they show the energy density of 47.7 and 147.3 Wh·kg−1 at the power density of 636.2 and 800 kW·kg−1, respectively. Otherwise, the flexible MnO2//S-Cu/Cu2O hybrid capacitor is assembled, which also exhibits good performance at different bending conditions. This work can provide a simple method to prepare the electrode materials via in situ anion modification for high-energy density battery-like energy storage systems.