Performance Supercapacitors Research Articles

Two-step hydrothermal synthesis of hydrangea-like Bi2O2Se with high performance for supercapacitors

The hydrangea-like structure of Bi2O2Se, composed of ultra-thin nanosheets, was prepared by a 2-step hydrothermal method for supercapacitor applications. The unique hydrangea-like structure of Bi2O2Se, characterized by a substantial specific surface area and abundant pore morphologies, facilitated the infiltration of electrolyte. The presence of bismuth vacancies not only enhanced the conductivity, but also increased the spacing between [Bi2O2]n2n+ and [Se]n2n– layers, creating room for K+ insertion/extraction and augmenting the surface-controlled pseudo-capacitance. Consequently, the hydrangea-like Bi2O2Se exhibited a high specific capacitance of 650 F/g at 1 A/g, excellent rate capability of 62 % from 1–20 A/g, and retained 80 % of its initial capacitance after 2000 cycles.

Enhancement of energy storage performance of supercapacitors based on MoS2-g-C3N4 Nanocomposite electrodes

Enhancement of energy storage performance of supercapacitors based on MoS2-g-C3N4 Nanocomposite electrodes

Enhanced Electrochemical Performance of NiMn Layered Double Hydroxides/Graphene Oxide Composites Synthesized by One-Step Hydrothermal Method for Supercapacitors.

This study aims to enhance the performance of supercapacitors, focusing particularly on optimizing electrode materials. While pure NiMn layered double hydroxides (LDHs) exhibit excellent electrochemical properties, they have limitations in achieving high specific capacitance. Therefore, this paper successfully synthesized composite materials of NiMn LDHs with varying loadings of graphene oxide (GO) using a hydrothermal method. Systematic physicochemical characterization of the synthesized materials, such as powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field-emission scanning electron microscopy (FE-SEM), and Raman spectroscopy, revealed the influence of GO doping on the microstructure and electrochemical performance of NiMn LDHs. Electrochemical tests demonstrated that the NiMn LDHs/GO electrode material exhibited optimal electrochemical performance with a specific capacitance of 2096 F g-1 at 1 A g-1 current density and 1471 F g-1 at 10 A g-1, when GO doping level was 0.45 wt %. Furthermore, after 1000 cycles of stability testing, the material retained 53.3 % capacitance at 5 A g-1, indicating good cyclic stability. This study not only provides new directions for research on supercapacitor electrode materials but also offers new strategies for developing low-cost and efficient electrode materials.

NiMn-Ag NWs complexes electrode material with in situ grown conductive 3D networks for enhanced supercapacitive performance by boosting Ni2+

Power density is one of the important factors affecting the performance of electrode materials, which is hampered by ion/electron transport and agglomeration build-up problems. In this study, a novel 3D NiMnO3/Ni(OH)2/Ag NWs composite is synthesized via the introduction of Ag NWs. The introduction of Ag NWs synergistically influences the crystal structure and micro-morphology of the NiMnO3/Ni(OH)2/Ag NWs composite. The unique pentatwinned structure of Ag NWs facilitates the enhancement of the (110) and (101) crystal planes, which induces the movement of Ni 2p3/2, leading to a significant increase of Ni2+ concentration in the composites. This ensures an abundance of ion adsorption sites, generating materials conducive to reactive activity. This new structure increases the density of active sites and establishes a conductive network, which optimizes the electron and ion transport paths, greatly reduces the diffusion resistance at the electrode-electrolyte interface, and improves the charge transfer efficiency, thus effectively increasing the specific capacity and energy density of the material. The NiMnO3/Ni(OH)2/Ag NWs//AC device exhibits a remarkable specific capacity of 350.478 mAh·g−1 at a current density of 0.01 A cm−2, and its Ragone plot reveals a peak energy density of 81.107 Wh kg−1 at a power density of 1699.871 W kg−1. Additionally, it achieves an energy density of 60.532 Wh kg−1 at a power density of 8490.072 W kg−1. This study explores the design and application of 3D structured electrode materials, which effectively improves the specific capacity of the materials and provides a new idea to further improve the energy density of supercapacitors.

Enhancing supercapacitor performance through cobalt compounds doping in nickel-vanadium hydrotalcite

Enhancing supercapacitor performance through cobalt compounds doping in nickel-vanadium hydrotalcite

Coal-based Si self-doped disordered porous carbon for supercapacitor electrodes

In preparing activated carbon for coal-based supercapacitors, silicon in coal usually requires removal with hydrofluoric acid, which is neither economical nor environmentally friendly. However, silicon can be used as the anode in lithium batteries due to its high theoretical capacity. So silicon was retained to study its effect on supercapacitors. By retaining silicon without hydrofluoric acid treatment and activating at lower temperature, the prepared Si-doped activated carbon achieved a high specific capacitance of 318.3F/g at 0.5 A/g in the three-electrode test system. Omitting hydrofluoric acid treatment increased the specific capacitance by 49 %. Experimental results show that this 4.92 % silicon doping, mainly CSiO3, is the main reason for the enhancement. Density functional theory (DFT) simulations confirmed that CSiO3 improves double-layer capacitance by localizing surface charge and enhancing electrolyte ion adsorption, while also boosting quantum capacitance. High activation temperatures increase coal-activator reactions but also decrease disorder of the carbon, reducing specific capacitance. Temperature experiments show that the specific capacitance increases and then decreases in the range of 600 ∼ 950 °C, and reaches a peak at 650 °C. This study presents a simple, effective method to enhance supercapacitor performance with silicon-carbon precursors and provides detailed explanation on the capacitance enhancement mechanism for the first time.

Phosphorus-doped carbon nitride for enhanced supercapacitor performance and energy storage applications

Exploiting the advantages of graphitic carbon nitride doped with phosphorus (xP-CN) electrodes were designed for high-performance hybrid asymmetric supercapacitor via facile hydrothermal and thermal decomposition techniques. The structural, surface chemistry, functional and morphological characterizations evidence depict successful phosphorus incorporation in Carbon Nitride (CN). X-ray photoelectron spectroscopy analysis shows that phosphorus (P) atoms have replaced corner carbon atoms in the CN structure. These findings clearly demonstrate that the presence of phosphorus doping improves the electrochemical activity of the electrodes. The designed three-electrode system has a specific capacitance of 189.36 F/g with a current density of 1 A/g. Phosphorus doping has been discovered to play a significant role in improving both specific capacitance and cycling stability. The capacitance retention of the two-electrode solid-state device has 97.2 % after 5000 cycles. These electrochemical evaluations reveal that the xP-CN electrode exhibits superior electrochemical performances than pristine CN. This doping strategy for CN presents a novel and efficient approach for crafting high-performance supercapacitors.

Synergistic effect of SGO/Nickel cobalt sulfide nanocomposite on Ni-foam for supercapacitor performance with widened potential windows − A microwave-assisted synthesis

Designing of high-performance supercapacitors with superior energy storage capabilities is crucial for addressing the growing demand for sustainable energy solutions. In this study, we investigate the synergistic effect of a sulfonated graphene oxide (SGO) /nickel-cobalt sulfide (NiCoS) nanocomposite on Ni-foam for supercapacitor applications. The SGO/NiCoS nanocomposite exhibits improved electrochemical performance, including increased specific capacitance, enhanced rate capability, and widened operating potential windows. The material exhibits a high energy density of 117.76 Wh/kg and a power density of 503.24 W/kg. The ASC also showed superior electrochemical stability, retaining 90 % of its coulombic efficiency after 10,000 cycles. The combination of NiCoS and SGO on Ni-foam significantly augments energy and power density, making it an attractive material for advanced supercapacitors. The microwave-assisted synthesis technique employed in this study enables rapid and uniform heating, reducing reaction times and improving selectivity. This work demonstrates the potential of SGO/ NiCoS nanocomposites on Ni-foam for supercapacitors, highlighting the benefits of synergistic material combinations and efficient synthesis methods.

Binary Biomass-Based Electrolyte Films for High-Performance All-Solid-State Supercapacitor.

Solid-state electrolytes have received widespread attention for solving the problem of the leakage of liquid electrolytes and effectively improving the overall performance of supercapacitors. However, the electrochemical performance and environmental friendliness of solid-state electrolytes still need to be further improved. Here, a binary biomass-based solid electrolyte film (LSE) was successfully synthesized through the incorporation of lignin nanoparticles (LNPs) with sodium alginate (SA). The impact of the mass ratio of SA to LNPs on the microstructure, porosity, electrolyte absorption capacity, ionic conductivity, and electrochemical properties of the LSE was thoroughly investigated. The results indicated that as the proportion of SA increased from 5% to 15% of LNPs, the pore structure of the LSE became increasingly uniform and abundant. Consequently, enhancements were observed in porosity, liquid absorption capacity, ionic conductivity, and overall electrochemical performance. Notably, at an SA amount of 15% of LNPs, the ionic conductivity of the resultant LSE-15 was recorded at 14.10 mS cm-1, with the porosity and liquid absorption capacity reaching 58.4% and 308%, respectively. LSE-15 was employed as a solid electrolyte, while LNP-based carbon aerogel (LCA) served as the two electrodes in the construction of a symmetric all-solid-state supercapacitor (SSC). The SSC device demonstrated exceptional electrochemical storage capacity, achieving a specific capacitance of 197 F g-1 at 0.5 A g-1, along with a maximum energy and power density of 27.33 W h kg-1 and 4998 W kg-1, respectively. Furthermore, the SSC device exhibited highly stable electrochemical performance under extreme conditions, including compression, bending, and both series and parallel connections. Therefore, the development and application of binary biomass-based solid electrolyte films in supercapacitors represent a promising strategy for harnessing high-value biomass resources in the field of energy storage.

Fabrication of asymmetric supercapacitors by laser processing of activated carbon-based electrodes produced from rice husk waste

The development of supercapacitors (SCs) by using carbon electrodes obtained from biomass waste simultaneously promotes the optimized use of the renewable energy by its high-powered storage, and the reduction of contamination in nature. Such industrial sector would be an excellent opportunity also for the developing nations, promoting their economic growth by the conversion of biowaste into added value goods. However, such carbon may not reach the desired performance for SCs. In this work, we used laser processing technology for enhancing the capacitance of SC electrodes composed of activated carbon obtained from rice husk produced in Nigerian farmlands. The activated carbon powder was synthesized by conventional carbonization-chemical activation processes and treated with microwaves. Afterwards, the CO2 laser processing of thin film electrodes composed of a mixture of the carbon powder with carbon black (conductive additive), and precursors as urea (for doping of the activated carbon with nitrogen), or manganese nitrate (for the crystallization of pseudocapacitive Mn3O4 nanoparticles on the carbon surface) was carried out for obtaining enhanced positrodes and negatrodes. The resulting hybrid electrodes exhibited a 3-fold increase of the capacitance (up to 134 F/g @ 10 mV/s) as compared to the raw carbon in the [0, 0.8] V potential window. Asymmetric SC devices integrated by carbon (-)//carbon-Mn3O4 (+) laser-treated electrodes, operating at 1.2 V voltage, revealed up to 300 × higher energy and power densities than symmetric SCs composed of raw carbon electrodes.

Nickel doped tungsten disulfide grown on carbon cloth for flexible supercapacitors

We present the synthesis of flower-shaped nickel-doped tungsten disulfide on flexible activated carbon cloth (ACC) using a simple hydrothermal technique for flexible symmetric supercapacitors. The nickel-to-tungsten disulfide doping ratio is optimized by adjusting the mass ratio of nickel and tungsten disulfide (Ni:WS2 = 0.5:3, 1:3, and 1.5:3) to enhance charge storage capability, surface area, impedance behavior, specific capacity, and rate capability. The improved supercapacitor performance is attributed to the increased electrochemically active surface area, reduced impedance, and phase engineering from 2 H to 1 T achieved through optimal nickel doping. At a current density of 1 A g−1, the flexible symmetric supercapacitor device (Ni-WS2-ACC device) demonstrates a specific capacitance of 259.2 F g−1, an energy density of 22.4 Wh kg−1, and a power density of 803 W kg−1. Moreover, the Ni-WS2-ACC device maintains consistent supercapacitive performance under various bending conditions. These results present a promising strategy for further enhancing tungsten disulfide-based flexible supercapacitors as energy storage devices.

Advancements in lithium zinc phosphate (LZP) nanoparticles: Enhanced electrochemical performance for high-efficiency supercapacitors

The synthesized LiZnPO4 nanoparticles were characterized at different temperatures like (400oC, 500 °C, 600 °C, and 700 °C) using various techniques including XRD, FTIR, FESEM, XPS, and electrochemical analyses. X-ray diffraction (XRD) analysis of LiZnPO4 nanoparticles sintered at temperatures from 400 to 700 °C revealed well-crystallized structures at 700 °C, with preferred orientations along (202) and (020) planes. The Scherrer formula was employed to determine crystallite sizes, showing an increase from 55 nm at 400 °C to 85 nm at 700 °C. The annealing temperature influences the formation of microspherical aggregates, determining their surface area and thereby affecting energy storage performance. Samples annealed at 700 °C exhibited a specific capacitance of approximately 268 F/g at a current density of 0.5 A/g and scan rate of 5 mV/s. Our studies indicate that LiZnPO4-based nanostructures have substantial potential for the development of hybrid supercapacitors.

Controlling of Crystal Facets by Dysprosium-Modified WO3/Carbon Nanofibers Enhance the Flexible Supercapacitor Performance.

Dysprosium-modified tungsten oxide/carbon nanofibers (Dy-WO3/PCNFs) are fabricated via electrospinning combined with high-temperature calcination to synthesize a flexible, self-supporting electrode material that does not require a conductive agent or binder. XRD and TEM analyses showed that introducing dysprosium promoted the preferential growth of WO3 crystals along the preponderance crystal planes involved in the electrochemical reaction, enhancing the exposure of the (002) and (200) crystal planes. Furthermore, DFT calculations demonstrated that the incorporation of Dy resulted in enhanced adsorption of Dy-WO3 by PCNFs, with an adsorption energy of -1.21eV. The Bader charge results indicate a transfer of 1.70 |e| from PCNFs to Dy-WO3. DFT calculations demonstrate that strong adsorption facilitates charge adsorption/desorption, which contributes to charge transfer and enhances storage capacity. The prepared Dy-WO3/PCNFs exhibited a high specific capacitance (557.28Fg-1 at 0.5Ag-1). Supercapacitors assembled with Dy-WO3/PCNFs as the positive electrode and CNFs as the negative electrode have high energy density (29.8Whkg-1 at a power density of 363.48Wkg-1). This study demonstrates the successful synthesis of Dy-WO3/PCNFs with exceptional electrochemical properties and offers significant insights into the design and application of flexible electrodes by incorporating dysprosium to modulate the crystal surface of WO3.

Butanedioic acid unlock shelf-stable Ti3C2Tx (MXene) dispersions and their electrochemical performance in supercapacitor

MXene experiences significant oxidation and gradual deterioration in aqueous media due to its inadequate chemical stability, which hinders its further advancement. This study presents a simple and effective approach to prevent the degradation of Ti3C2Tx MXene nanosheets in aqueous media by chemically encapsulating with butanedioic acid (succinic acid (SSA)). Specifically, the impact of pH and antioxidant content on the rate of oxidation of Ti3C2Tx is investigated together with their electrochemical behavior at different intervals. The research demonstrates that the oxidation rate of MXene must be prevented at a suitable concentration of antioxidants; higher doses of antioxidants cause aggregation, while lower concentrations accelerate the oxidation process. Furthermore, fluctuations in pH levels within the dispersion indicate that under acidic conditions, MXene experiences a greater level of oxidation as a result of elevated proton reactivity, which ultimately leads to material degradation. On the other hand, alkaline environments tend to reduce oxidative reactions, leading to increased stability of MXene. Consequently, MXene-SSA can demonstrate long-term stability in water for up to 35 weeks. The electrochemical properties of SSA-encapsulated MXene sheets are assessed as a supercapacitor electrode throughout a time gradient. In comparison to fresh MXene (299 F g−1 at 1 A g−1), the specific capacitances of SSA-protected MXene (321 F g−1 at 1 A g−1) remain unchanged after a long time. Based on DFT calculations, it has been observed that succinic acid creates beneficial hydrogen bonding interactions with Ti sites that possess a lower coordination number, hence improving the stability of Ti3C2Tx.

Enhanced supercapacitive performance in Cu doped Sn3O4 synthesized by a simple extract route

The synthesis of nanomaterials using plant extracts is of great importance for a sustainable, chemical-free future. In this study, multivalent Sn3O4 doped with Ni and Cu were synthesized by a simple, low-cost method using Moringa oleifera leaf extract at low temperature and investigated for supercapacitor applications. Various characterizations indicate that the synthesized samples crystallize in a triclinic space group and have a larger surface area of 109.2 m2/g, which is advantageous for electron and ion transport. Electrochemical studies were carried out by cyclic voltammetry, galvanostatic charge/discharge, impedance spectroscopy and cycle life measurements in 6 M KOH electrolyte. Cu-doped Sn3O4 showed the highest capacitance of 608 C/g at a current density of 1 A/g. An asymmetric device built with it delivered an energy density of 31.5 Wh/Kg at a power density of 1400 W/Kg and retained 85 % capacity even after 6000 continuous cycles. The results show that extract-based synthesis of multivalent oxides is beneficial not only for a sustainable environment but also for achieving superior capacity.

Harnessing dysprosium telluride/GPE as an effective electrode for energy storage and conversion

Hydrogen stands out as a clean alternative to fossil fuels, and its production via water electrolysis is promising, although the slow kinetics of the oxygen evolution reaction (OER) pose a significant challenge. Alongside energy conversion, the quest for effective energy storage remains critical. This study explores the potential of dysprosium telluride (Dy2Te3) as a highly efficient catalyst for OER and a supercapacitor electrode. The hydrothermally synthesized Dy2Te3 exhibits exceptional OER activity, characterized by an overpotential of 294 mV at 1.48 V vs. RHE, a low Tafel slope of 48 mV dec−1, and minimal interfacial resistance of 13 Ω. In a 1.0 M KOH solution, Dy2Te3 nanoparticles demonstrate outstanding supercapacitor performance, achieving a power density of 283.5 W kg−1, specific capacitance of 645.33 F g−1, and energy density of 22.8 Wh kg−1 at 1 A g−1. The high performance is attributed to enhanced electrical conductivity and a low impedance of 0.352 Ω in a three-electrode system. In a practical two-electrode configuration, Dy2Te3 nanoparticles deliver a specific capacitance of 479 F g−1, energy density of 94 Wh kg−1, and power density of 0.32 kW kg−1, with a reduced interfacial resistance of 1.03 Ω. These results underscore the potential of Dy2Te3 as a viable electrode material for both supercapacitors and water splitting, offering valuable insights into the application of lanthanide-based metal chalcogenides in energy technologies.

Green Power: The Role of Plant-Based Biochar in Advanced Energy Storage.

This comprehensive review aims to provide an overview of recent progress in utilizing plant-based biochar for supercapacitors. It specifically focuses on biochar derived from plant biomass such as agricultural residues, weeds and aquatic plants, examining their potential in energy storage applications. It explores various synthesis methods like pyrolysis and hydrothermal carbonization and evaluates their impact on biochar's structure and electrochemical properties. Additionally, it examines the electrochemical performance of biochar-based supercapacitors, focusing on parameters such as capacitance, cycling stability, and rate capability. Strategies to enhance biochar's electrochemical performance, such as surface modification and composite fabrication, are also discussed. Furthermore, it addresses existing challenges and prospects in harnessing plant-based biochar for supercapacitor applications, highlighting its potential as a sustainable and efficient electrode material for next-generation energy storage devices.

Vacancy Engineering of Selenium-Vacant NiCo2Se4 with Enhanced Electrochemical Performance for Supercapacitor.

Vacancy engineering effectively modulates the electronic properties of electrode materials, thereby improving their electrochemical performance. In this study, we prepared selenium-deficient NiCo2Se4 (Sev-NCS) using ethylene glycol as a reducing agent in NaOH alkaline environment, and investigated its potential as an electrode material for supercapacitors. Both theoretical and experimental results confirmed that the introduction of vacancies altered the morphology and electronic structure of NiCo2Se4, which in turn synergistically improved the conductivity and the diffusion capability of electrolyte ions. The optimized Sev-NCS electrode achieved an excellent specific capacitance of 2962.7 F g-1 at a current density of 1 A g-1 and superior cycling stability with a capacitance retention of 89.5% even after 10,000 cycles. Furthermore, an asymmetric device composed of the optimized Sev-NCS electrode as the positive electrode and activated carbon as the negative electrode achieved an energy density of 55.6 Wh kg-1 at a power density of 800 W kg-1. Therefore, this work offers novel insights into the role of vacancy engineering in improving the performance of transition metal compound-based electrode materials for supercapacitor.

Two-step cathodic microwave electrodeposition for construction of Co9S3(OH)5@Ni(OH)2 hetero-structure as supercapacitor electrode materials

The preparation of two-phase electrode materials of Co9S8@Ni(OH)2 typically involves a laborious three-step process. In this study, a two-step cathode microwave electrochemical method was proposed for the fabrication of Co9S8@Ni(OH)2 electrode materials for supercapacitors, eliminating the need for precursor synthesis. This approach not only simplified the preparation process and saved time but also successfully produced a p-n heterostructure electrode material consisting of Co9S8@Ni(OH)2 phases, where the Co9S8 phase has a chemical formula of Co9S3(OH)5. This unique structure is capable of inducing an internal electrical field by facilitating the transfer of charge carriers from Co9S3(OH)5 to Ni(OH)2, thereby enhancing charge transfer kinetics. As a result, the electrode exhibited remarkable supercapacitive performance, achieving a high specific capacitance of 255.4 mAh g-1 (7.56 F cm-2) at 1 A g-1. Even at a 20-fold increase in charge/discharge current density, the specific capacitance remained high at 218.9 mAh g-1 (6.48 F cm-1), retaining 85.8 % of the initial capacity. Furthermore, the Co9S3(OH)6@Ni(OH)2 electrode materials demonstrated excellent durability, enduring 10000 cycles with a capacitance retention of 92.9 % of the initial value. An asymmetric supercapacitor constructed with Co9S3(OH)5@Ni(OH)2 as the anode and a commercial active carbon film as the cathode was able to power a red light diode continuously emitting light for up to 42 min.

Enhancing the supercapacitive performance of soot material induced with manganese cobaltite (MnCo2O4) for supercapacitor application

Processing waste carbonaceous materials into useful products presents a sustainable alternative to its recovery. An effective and environmentally benign way of reusing such waste is to convert them into electrodes capable of supporting energy conversion reactions. This study introduces a cost-effective synthesis of a composite electrode for supercapacitor application using a waste carbonaceous soot obtained from Tema Steels Limited, a local steel manufacturing company in Ghana, having it subjected through thermal treatment at 500 °C and synergizing with annealed MnCo2O4 to augment the soot’s supercapacitive capabilities. The fabricated composite electrode comprises treated (thermally activated) soot combined with annealed MnCo2O4 material in 1:1 mass ratio, using a facile hydrothermal synthesis technique. Halogen like chlorine negatively affect the supercapacitive performance of soot, the as-received soot was subjected to a 500°C, 2-hour thermal treatment to optimize its performance, effectively reducing chlorine content from 4.1 to 2.1 at. weight percent and notably augmenting its specific surface area (SSA). SSA increased from 183.3 m2g−1 to 253.3 m2g−1, a 27.6 % increment after thermal treatment. The electrode’s supercapacitive performance was utilized using a 3 M KOH electrolyte solution employed in a three-electrode system. Attaining a current density of 3Ag−1, the composite electrode achieved a specific capacitance of 2818 Fg−1. The fabricated composite electrode demonstrated a stable charge/discharge capability by retaining around 87 % of its capacity after 10,000 cycles, establishing its practicality for applications in electrochemical storage.