High-performance Supercapacitors Research Articles

Hierarchical porous MXene film with diffusion path optimization for supercapacitor

MXenes have immense potential in electrochemical energy storage owing to their outstanding physicochemical properties such as their oxygen-containing groups that impart additional pseudocapacitance to acidic electrolytes. However, during electrode assembly, MXene nanosheets undergo restacking because of hydrogen bonding and van der Waals forces, which causes electrolyte ions to traverse long diffusion pathways between the long and narrow nanosheets. Exploiting the oxidative properties of Ti3C2Tx, a hierarchical porous MXene film with micro-, meso- and macroporous structures was successfully prepared using a simple hydrothermal oxidation and etching process to create micro- and mesoporous structures, followed by ice templating to prepare three-dimensional (3D) linked macroporous structures. Because these hierarchical pores have synergistic effects on electrochemical activity and electrolyte ion diffusion, the film attained a specific capacitance of 539F/g at a current density of 2 A/g when it was used as a supercapacitor electrode, which corresponds to one of the highest values reported for MXene-based electrodes. The film retained 83% of its specific capacitance when the current density was increased to 40 A/g, and exhibited excellent cycling stability. By using this multi-porous MXene design, synergistic improvement in ion diffusion was successfully realized and thus a new strategy to prepare high-performance supercapacitor electrode materials was developed.

MoS2/Yb, Er-doped CeO2 composite synthesized by hydrothermal method for high-performance supercapacitor applications

MoS2/Yb, Er-doped CeO2 composite synthesized by hydrothermal method for high-performance supercapacitor applications

High-value conversion of invasive plant into nitrogen-doped porous carbons for high-performance supercapacitors

Given the harm caused by invasive plants to the environment and the high cost of treatment, we propose high-value transformation and utilization for invasive plants. Highly porous carbon derived from invasive plant (Canada goldenrod) was successfully synthesized through a feasible and green carbonization approach, which was firstly utilized as supercapacitor electrode. It is found that the addition of nitrogen (N)-rich chlorella could positively increase the N content and considerably boost the specific surface area up to 2231.41 m2 g-1 for the resultant Carbon-GC1-800, which are crucial factors for accelerating the ion transport and improving the capacitive behaviors. Notably, Carbon-GC1-800 exhibits the highest ratio (70.9%) of microporous volume to total pore volume. The electrochemical properties of Carbon-GC1-800 electrode exhibits an outstanding specific capacitance of 388.2Fg-1 at a current density of 0.5Ag-1 and a superb rate capability of 75.7% from 0.5Ag-1 to 10Ag-1. The assembled symmetric supercapacitor with ionic liquid as electrolyte demonstrates the exceptional maximum power density of 8753.7Wkg-1 and peak energy density of 59.3Whkg-1. This study presents the novel ideas and effective techniques to produce porous carbons for energy storage from invasive plant resources.

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.

High-Performance Aqueous Supercapacitors Based on a Self-Doped n-Type Conducting Polymer.

Environmentally-benign materials play a pivotal role in advancing the scalability of energy storage devices. In particular, conjugated polymers constitute a potentially greener alternative to inorganic- and carbon-based materials. One challenge to wider implementation is the scarcity of n-doped conducting polymers to achieve full cells with high-rate performance. Herein, this work demonstrates the use of a self-doped n-doped conjugated polymer, namely poly(benzodifurandione) (PBDF), for fabricating aqueous supercapacitors. PBDF demonstrates a specific capacitance of 202 ± 3 Fg-1, retaining 81% of the initial performance over 5000 cycles at 10 Ag-1 in 2m NaCl( aq ). PBDF demonstrates rate performances of up to 100 and 50 Ag-1 at 1 and 2mgcm-2, respectively. Electrochemical impedance analysis reveals a surface-mediated charge storage mechanism. Improvements can be achieved by adding reduced graphene oxide (rGO), thereby obtaining a specific capacitance of 288 ± 8 Fg-1 and high-rate operation (270 Ag-1). The performance of PBDF is examined in symmetric and asymmetric membrane-less cells, demonstrating high-rate performance, while retaining 83% of the initial capacitance after 100000 cycles at 10 Ag-1. PBDF thus offers new prospects for energy storage applications, showcasing both desirable performance and stability without the need for additives or binders and relying on environmentally friendly solutions.

Fabrication of high-performance asymmetric supercapacitor using hybrid niobium (V) oxide anchored La2O3 nanocomposite for high energy density performance

Fabrication of high-performance asymmetric supercapacitor using hybrid niobium (V) oxide anchored La2O3 nanocomposite for high energy density performance

Preparation of N and S heteroatoms doped activated carbon from stalks of Gossypium hirsutum L. flower for high-performance symmetric supercapacitor application

Preparation of N and S heteroatoms doped activated carbon from stalks of Gossypium hirsutum L. flower for high-performance symmetric supercapacitor application

Carbon bi-metallic molybdenum tungsten oxide composite as a potential electrode for high-performance asymmetric supercapacitor

Molybdenum tungsten oxide (MTO) bi-metallic structure was synthesized using Pechini method. Asymmetric supercapacitor (SC) was constructed using MTO/ active carbon (AC) and H2SO4 electrolyte. Different AC: MTO weight ratios proved a high impact on composite electrochemical performance. Galvanostatic charge-discharge tests demonstrated a capacitance of 336.75 F/g, with 37.11 % capacitance shrinking upon increasing the applied current to 5 A/g (50-fold) from 0.1 A/g. Such high-rate capabilities were attributed to lattice spacing induced by inserting tungsten (W) into the MO lattice. The optimized ratio of MTO/AC possesses a high specific energy and power of ∼120 Wh/kg and 256 kW/kg at 0.1 and 80 A/g, respectively. Moreover, the composite is showing ∼100 % retention values after 20k cycling at a high current of 80 A/g. Unlike many reports of using first-class transition metal oxides for energy storage devices, bi-heavy metal composite functionalization in SC applications is scarce. This potential composite between porous carbon and bi-heavy metal oxide suggested talented electrode materials for energy storage systems.

High-performance supercapacitor materials based on NiMn-LDH layered structures with MXene layers

In recent years, the environmental degradation exacerbated by extensive fossil fuel use has underscored the urgent need for cleaner and more efficient energy storage systems. This study addresses the challenges faced by hybrid supercapacitors (HSCs), which, despite their high power density and long lifespan, still suffer from low energy density and high self-discharge rates. We employ a co-precipitation method to integrate MXene with NiMn-layered double hydroxides (LDHs), optimizing the performance of HSCs. The incorporation of MXene enhances the conductivity and structural stability of NiMn-LDH, addressing issues of poor conductivity and instability during cycling. The developed NiMn-LDH@MXene electrodes demonstrate remarkable electrochemical performance, including a specific capacitance of 1530 F g⁻¹ at 2 A g⁻¹, a capacity retention rate of 90.52 % after 20,000 cycles at 10 A g⁻¹, a high energy density of 60.56 Wh kg⁻¹, and an excellent power density of 924.95 W kg⁻¹. This research not only marks a significant advancement in electrode material performance but also provides valuable insights into the development of next-generation energy storage devices with enhanced stability and efficiency.

Rice husk-derived nitrogen-doped graphitic carbon/graphene nanosheets self-assembly for high-performance supercapacitors with chemical blowing method

Carbon materials derived from waste biomass are increasingly popular in energy devices due to their renewability, environmental benefits, and rich heteroatom functionalization. Herein, a simple and low-cost method for synthesising rice husk-derived nitrogen-doped graphitic carbon/graphene nanosheets (RNGNs) by chemical blowing was developed. Carbon was derived from rice husk (RH), while nitrogen was sourced from ethylenediaminetetraacetic acid and iron sodium salt hydrate (EDTA-FE), serving multiple roles as a blowing agent, an activating agent and a graphitization catalyst in a closed system. This approach facilitates the formation of a unique 3D structure of 2D graphene self-assembly on the wrinkled surface of graphitic carbon. As an electrode material for supercapacitors, the obtained RNGN800–1:1 with high nitrogen content (5.02 %) shows good electrical conductivity and a large specific surface area (1130 m2 g−1). These characteristics bring about an impressive electrochemical performance (334.5 F g−1 at 0.5 A g−1, 75.6 % retention at 20 A g−1). Moreover, when assembled into symmetrical device, the RNGN800–1:1 demonstrates a high power density of 9.4 kW kg−1and an excellent energy density of 15.2 Wh kg−1 with outstanding long-term cyclability (remains 94.77 % after 25000 cycles). This study introduces a straightforward and environmentally friendly approach for synthesizing nitrogen-doped graphitic carbon/graphene nanosheets from sustainable biomass resources. The resulting material is expected to have broad applications across various areas, including adsorption, catalysis, and energy storage.

High-performance NF-loaded F-NiFe-LDH/rGO nanoflower/nanosheet composite electrode material achieving enhanced specific capacitance and energy density for supercapacitor

High-performance nanostructured F-NiFe-LDH/rGO composite electrode materials with F-NiFe-LDH nanoflowers and rGO nanosheets are synthesized in a controlled hydrothermal method by leveraging the strong synergistic effects between the components, enabling the construction of F-NiFe-LDH/rGO//AC asymmetric supercapacitors. The incorporation of rGO significantly enhances electron transport, resulting in an exceptional specific capacitance of 2860 F g−1 at a current density of 1 A g−1, with a remarkable capacity retention of 102 % after 1000 cycles. This represents a notable improvement in electrochemical energy storage, with surface-controlled capacitance contributing more in alkaline electrolytes for F-NiFe-LDH/rGO composite compared to F-NiFe-LDH alone. The asymmetric supercapacitor device exhibits a specific capacitance of 354 F g−1 at 1 A g−1, maintaining 92.31 % of its initial capacitance after 1000 charge/discharge cycles at 5 A g−1, and achieves an impressive energy density of 110 Wh kg−1 at 1 A g−1. The innovation of this work lies in the controllable preparation of nanostructured F-NiFe-LDH-rGO supercapacitor electrode material with enhanced specific capacitance and energy density by the synergistic effect between F-NiFe-LDH and rGO. This work offers a solid foundation for creating high-performance supercapacitor electrode materials and devices for energy storage applications.

Uniform carbon pillars array grown on boron doped diamond for high-performance supercapacitors and hydrogen evolution reactions

Carbon materials have marvelous ability in energy storage and microelectronics as a result of the high specific surface area and electrical conductivity. However, the low stability and the low power density caused by low potential window make it particularly difficult for their application in aqueous electrolysis. In this study, boron doped diamond (BDD) with wide potential window is used as substrate and Ni as catalyst to grow uniform carbon pillars (CP) by microwave plasma chemical vapor deposition method. The composite structure (CP/BDD) yields significant specific capacity (91.64 mF cm−2 at 0.1 mA cm−2) and cycling stability (92.3 % retention rate after 20,000 cycles) when used as the electrode of supercapacitors, superior to most of BDD-based electrodes. The prepared symmetrical supercapacitor devices maintain their excellent electrochemical performance characteristics (power density of 4.4 mW cm−2 and energy density of 13.4 μW h cm−2), as well as high cycling stability. In addition, the electrode has considerable application potential in electrochemical hydrogen production with low hydrogen evolution potential and small Tafel slope value. These results illustrate the potential of BDD based composites for using as energy storage electrodes for electronic products and energy conversion equipment.

NiMoO4@NiSe2 microspheres as electrode materials for high-performance supercapacitor

Supercapacitors as novel sustainable energy conversion systems have been a hot spot owing to their high specific capacitance and excellent cycle stabilities. However, the poor electron conductivity limits their further applications. Herein, we synthesize NiMoO4@NiSe2 samples by a controllable hydrothermal route. The heterogeneous structure consists of high conductive nanosheets and high capacitive particles. It can slow down the collapse of electrode materials and enhance the conductivity of material. It also facilitates ion diffusion and faradaic redox reaction, thereby improves the electrochemical performance. The as-synthesized electrode presents a specific capacity of 1193 C g-1 at 1 A g-1 and maintains 82.9 % of the initial capacitance after 10,000 times cycles. A hybrid capacitor is constructed using the composites as the electrode material. It possesses a capacitance of 101 C g-1 at 1 A g-1 and 85.8 % of the retention rate after 10,000 times charging-discharging. This impressive performance of composite could be attributed to their mesoporous surface with high specific surface area (48 m2g-1). Moreover, the supercapacitor shows excellent flexibility after folding, exhibiting a wide application prospect in the field of supercapacitors.

Pillar-Supported 2D Layered MOFs with Abundant Active-Site Distributions for High-Performance Alkaline Supercapacitors.

The development of two-dimensional (2D) layered metal-organic frameworks (MOFs) through precise molecular-level design and synthesis has emerged as a prominent research endeavor. However, the utilization of MOFs in their pristine form as electrodes for supercapacitors poses a significant challenge due to their limited tolerance in alkaline environments. To address these issues, we have developed Co- and Cu-based pillar-layered MOFs by regulating the structure of their inner layers through introducing an alkaline N-containing "pillar" to enhance the performance of alkaline supercapacitor electrodes. From the microstructure study and theoretical calculation, the high-density redox centers and efficient chemical bonding modes of Co-MOF determine a unique electron conduction pathway, resulting in excellent energy storage performance. This study underscores the significance of chemical bonding modes and active-site distribution in enhancing the energy storage capabilities of pillar-layered MOFs in alkaline environments, presenting a promising approach for the development of high-performance MOF-based materials for supercapacitor applications.

Unlocking hierarchical hollow nanoblocks of NiMo sulfide with extended interlayer spacing of Mo-S units for high-performance supercapacitor

Molybdenum sulfide (MoS2) has been investigated as electrode of supercapacitor due to its unique structure. However, the restricted availability of active sites and sluggish behavior at the basal surface impede its improvement. Here we propose an unlocking hierarchical hollow strategy to synthesis the bimetallic sulfide heterostructures loaded on the ultrathin carbon (NiS/MoS2@UC). The unlocking hierarchical hollow structure and extended S-Mo layer provide interconnected channels for rapid electrolyte ion transport, while the heterojunction interface promotes the electron transfer and redox reaction. As a result, NiS/MoS2@UC − 2 exhibits a high specific capacitance of 616.7F g−1 at the current density of 1 A/g, which is approximately 10 times higher than that of MoS2@UC and 6 times higher than that of NiS@UC. Moreover, NiS/MoS2@UC − 2 demonstrates a high energy density of 7.7 Wh kg−1 at the power density of 300 W kg−1 with excellent cycling durability.

A facile one-step route to synthesize of novel porous reduced graphene oxide@nickel sulfide (rGO@Ni3S2) core shell nanostructures for high-performance supercapacitor electrodes

In the last decade, there has been significant interest in the use of supercapacitors with high power density and cycle stability in a wide range of applications. Graphene-based hybrid electrodes are considered a very promising option for supercapacitors owing to the synergistic effects they exhibit. In this study, we provide a novel and efficient method for synthesising a core-shell nanocomposite consisting of reduced graphene oxide (rGO) wrapped around nickel sulphide (Ni3S2) using a one-step hydrothermal process. The resulting rGO@Ni3S2 composite exhibits excellent performance as a supercapacitor electrode while also being cost-effective. As a promising supercapacitor electrode, a relatively high specific capacitance of 1052.5 Fg−1 at current density of 1 Ag−1 in 1 mol.L−1 KOH aqueous solution, along with good cycling stability (with a 94.5 % retention rate after 10,000 cycles) were demonstrated for the rGO@Ni3S2 core shell composite electrode. In addition, excellent electrochemical performances were also demonstrated for the asymmetric supercapacitor (ASC) by using rGO@Ni3S2 as the cathode and activated carbon, respectively. The fabricated ASC showed with a high energy density of 61.9 Whkg−1 at the power density of 585.7 W kg−1. Such high performance of rGO@Ni3S2 core shell electrode can enrich the prospects for future practical applications in energy storage.

One-dimensional lepidocrocite titania mesoparticles integrated with activated carbon for high-performance supercapacitor applications

Herein, we mix titania-based, TiO2, porous mesostructured, comprised of one-dimensional lepidocrocite nanofilaments, 1DLs, ≈ 5 × 7 Å2 in cross-section, with activated carbon, AC, to create unique composite structures with exceptional electrochemical properties. The synthesis method is facile, cost-effective, and scalable. While the porous mesoparticles, PMs, possess excellent protonic conductivity and exhibit enhanced faradic behavior in acidic aqueous media, their low electronic conductivity restricts their power output. The problem is solved by mixing the PMs with AC powders with various loadings. Electrolytes used were sulfuric acid, H2SO4, potassium hydroxide, KOH, lithium and Na-sulphates. The best PM loading was found to be 25 wt%. The resulting composite exhibits a specific capacitance (capacity) of 1024 Fg−1 (554 mAhg−1) at a 2 mVs−1 scan rate, with 97 % cyclic stability over 10,000 cycles when the electrolyte was 1 M H2SO4. Upon integration into a symmetrical device, the composite exhibited a specific energy of 135 Whkg−1 at 0.5 Ag−1. Further, it demonstrated a peak specific power of 18 kWkg−1, while retaining a specific energy of 54 Whkg−1 at 5 Ag−1. Notably, following 100,000 cycles at 1 Ag−1, the symmetrical cell sustained approximately 50 % of its initial specific capacitance. Subsequently, a 24 h self-discharge test revealed a decrease in cell voltage from 1.95 V to 0.48 V, thereby highlighting the potential suitability of these supercapacitors for short-term energy storage applications.

Heteroatom self-doped hierarchical porous carbon from nitrogen-rich jack bean meal for high-performance supercapacitor and efficient oxygen reduction

Heteroatom self-doped hierarchical porous carbon from nitrogen-rich jack bean meal for high-performance supercapacitor and efficient oxygen reduction

MnOx Embedded in Silicon Nanowire Arrays for High-Performance Supercapacitors

MnOx Embedded in Silicon Nanowire Arrays for High-Performance Supercapacitors

Soy protein isolate–based gel polymer electrolyte for flexible solid-state supercapacitor

At present, the polymer matrices of most polymer electrolytes are derived from petroleum-based synthetic polymers. Herein, sustainable and renewable soy protein isolate (SPI) was grafted with methacrylic acid (MAA) and then cross-linked by ring-opening reaction with polyethylene glycol diglycidyl ether as cross-linking agent to obtain a biomass-based polymer electrolyte. Results show that when the added amount of MAA is twice the quality of SPI, gel polymer electrolyte displays the best comprehensive properties and presents the highest ionic conductivity of 5.24 × 10−3 S/cm. The flexible supercapacitor was fabricated by using SPI-based gel polymer electrolyte with activated carbon electrodes, which exhibited excellent specific capacitance (128.63 F/g) and energy density (9.52 Wh/kg) at 0.5 A/g with a decent capacitance retention of 93% after 5000 charge–discharge cycles. It can be ascribed that grafting modification of SPI improves the interface performance of electrode–polymer electrolyte. Furthermore, potassium iodide is introduced to form a redox polymer electrolyte to achieve a high-energy-density supercapacitor, which provides outstanding energy density of 24.40 Wh/kg at 1.0 A/g. This work demonstrates that sustainable and renewable biomass can be converted into matrix of polymer electrolyte for high performance supercapacitor based on aqueous polymer electrolyte.