High-performance Supercapacitor Electrode Research Articles

Synthesis and Characterization of Modified Centrifuged-Electrospun Carbon Nanofibers for High-Performance Supercapacitor Electrodes

Background: Incorporating novel multifunctional effective materials into supercapacitors electrode is an ongoing requirement for hybrid supercapacitors with enhanced electrochemical performance. Methods: Herein, modified plasma-grafted multiwalled carbon nanotubes (CMS) with improved dispersion are embedded within centrifugal-spun carbon nanofibers as a hierarchical template (CNFs-CMS) to facilitate the growth of subsequent active materials. CNFs-CMS is then electroless plated with acicular nickel (Ni) balls, followed by one-step hydrothermal co-deposition to grow Ni(OH)2-MnO2 hybrid nanosheets. Significant findingsA binder-free, 3D interconnected nanostructures of CNFs-CMS@Ni@Ni(OH)2-MnO2 electrode material is employed for an all-in-one hybrid supercapacitor that exhibits excellent electric double layer (EDLC), battery-like and pseudocapacitance (PC) properties, along with a high surface area (665 m2 g−1) and conductivity (2.96 S cm−1). The as-fabricated electrode demonstrates specific capacitance (Cs) of 1063.33 F g−1 at a high current density of 20 A g−1 in 3M KOH electrolyte, maintaining capacitance retention of 92.5 % after 10,000 galvanostatic charge-discharge cycles. An asymmetric supercapacitor pairing CNFs-CMS@Ni@Ni(OH)2-MnO2 with CNFs-CMS is established, attributes comparably high energy density (52.54 Wh kg−1) and power density (59 kW kg−1) across a potential window of 1.2 V.

Enriched performance of practical device assisted asymmetric supercapacitor: NiO/Co3O4 intercalated with rGO nanocomposite electrodes

In this present report, we developed high performance supercapacitor electrode material of NiO/Co3O4/rGO ternary nanocomposites synthesized by a hydrothermal method with a different nickel and cobalt molar proportions. The phase formation, surface morphology and elemental information studies of binary NiO/Co3O4 and ternary NiO/Co3O4/rGO nanocomposites were investigated. The electrochemical investigations of the binary and ternary nanocomposites electrodes have been examined. Compare with various molar proportions, the ternary NiO/Co3O4(1,3)/rGO nanocomposites shows an extraordinary capacitance value of 980 Fg−1 at 1 Ag−1 as well as robust cycle life (cyclic retention of 92 % over the 5000 cycles at 10 Ag−1). In 0–1.4 V, an asymmetric supercapacitor attained a specific capacitance of 87.2 Fg−1 and large power density (1396.3 W/kg) with extreme energy density (23.7 Wh/kg). Moreover, assembled device reveals a great rate capability (89 % over the 5000 cycles in the electrolyte of PVA-KOH). The ternary electrode has high capacitance, capacitance retention and large energy density due to NiO and Co3O4 nanoparticles being intercalated with the high surface of rGO, as well as the synergetic effect of NiO/Co3O4 and rGO.

Regulating porous structure of coal-derived carbon materials by a dual-activation for high performance supercapacitors

Porous carbon plays an important role in supercapacitors with its favorable electrical conductivity, highly porous structure and superior chemical stability. However, the deep and tortuous ultramicropores in porous carbon greatly restricts the transport and transfer of electrolyte ions, resulting in the inferior electrochemical performance. Therefore, we propose a facile and green chemical activation method that uses KHCO3 and Zn(CH3COO)2·2H2O as dual activators to modulate the porous carbon structure. The synergistic activation between KHCO3 and Zn(CH3COO)2·2H2O endows the obtained porous carbons with hierarchical porous structure, honeycomb-like morphology and large specific surface area (1282 m2 g−1). In the three-electrode system, the optimal sample displays superior rate performance (70 % capacitance retention @ 50 A g−1) and high specific capacitance (321 F g−1 @ 1 A g−1). Symmetric two-electrode configurations were tested in 6 M KOH electrolyte, splendid cycling stability was observed (100 % capacity maintained after 10,000 cycles at 5 A g−1). Moreover, the symmetric supercapacitor assembled with neat EMIM BF4 as the electrolyte reveals a high energy density of 33 Wh kg−1 @ 624.6 W kg−1. This work offers new insights to manipulate the morphology and pore structure of coal-derived porous carbon for high performance supercapacitor electrode.

Optimization of a Conductive Polymer Layer on MOF-Derived Carbon Materials for High-Performance Supercapacitor Electrodes

Optimization of a Conductive Polymer Layer on MOF-Derived Carbon Materials for High-Performance Supercapacitor Electrodes

Facile Synthesis of Nitrogen-Doped Graphene Quantum Dots/MnCO3/ZnMn2O4 on Ni Foam Composites for High-Performance Supercapacitor Electrodes.

This study reports the facile synthesis of rationally designed composite materials consisting of nitrogen-doped graphene quantum dots (N-GQDs) and MnCO3/ZnMn2O4 (N/MC/ZM) on Ni foam using a simple hydrothermal method to produce high-performance supercapacitor applications. The N/MC/ZM composite was uniformly synthesized on a Ni foam surface with the hierarchical structure of microparticles and nanosheets, and the uniform deposition of N-GQDs on a MC/ZM surface was observed. The incorporation of N-GQDs with MC/ZM provides good conductivity, charge transfer, and electrolyte diffusion for a better electrochemical performance. The N/MC/ZM composite electrode delivered a high specific capacitance of 960.6 F·g-1 at 1 A·g-1, low internal resistance, and remarkable cycling stability over 10,000 charge-discharge cycles. Additionally, an all-flexible solid-state asymmetric supercapacitor (ASC) device was fabricated using the N/MC/ZM composite electrode. The fabricated ASC device produced a maximum energy density of 58.4 Wh·kg-1 at a power density of 800 W·kg-1 and showed a stable capacitive performance while being bent, with good mechanical stability. These results provide a promising and effective strategy for developing supercapacitor electrodes with a high areal capacitance and high energy density.

Electrodeposited Copper Tin Sulfide/Reduced Graphene Oxide Nanospikes for a High-Performance Supercapacitor Electrode.

Copper tin sulfide, Cu4SnS4 (CTS), a ternary transition-metal chalcogenide with unique properties, including superior electrical conductivity, distinct crystal structure, and high theoretical capacity, is a potential candidate for supercapacitor (SC) electrode materials. However, there are few studies reporting the application of Cu4SnS4 or its composites as electrode materials for SCs. The reported performance of the Cu4SnS4 electrode is insufficient regarding cycle stability, rate capability, and specific capacity; probably resulting from poor electrical conductivity, restacking, and agglomeration of the active material during continued charge-discharge cycles. Such limitations can be overcome by incorporating graphene as a support material and employing a binder-free, facile, electrodeposition technique. This work reports the fabrication of a copper tin sulfide-reduced graphene oxide/nickel foam composite electrode (CTS-rGO/NF) through stepwise, facile electrodeposition of rGO and CTS on a NF substrate. Electrochemical evaluations confirmed the enhanced supercapacitive performance of the CTS-rGO/NF electrode compared to that of CTS/NF. A remarkably improved specific capacitance of 820.83 F g-1 was achieved for the CTS-rGO/NF composite electrode at a current density of 5 mA cm-2, which is higher than that of CTS/NF (516.67 F g-1). The CTS-rGO/NF composite electrode also exhibited a high-rate capability of 73.1% for galvanostatic charge-discharge (GCD) current densities, ranging from 5 to 12 mA cm-2, and improved cycling stability with over a 92% capacitance retention after 1000 continuous GCD cycles; demonstrating its excellent performance as an electrode material for energy storage applications, encompassing SCs. The enhanced performance of the CTS-rGO/NF electrode could be attributed to the synergetic effect of the enhanced conductivity and surface area introduced by the inclusion of rGO in the composite.

Transforming polymeric air filters into high-performance supercapacitor electrodes through carbonization and fluorination

The global surge in disposable mask usage during the COVID-19 pandemic raises environmental concerns due to improper disposal. This study proposes an innovative method to repurpose polypropylene (PP) from disposable masks into highly efficient supercapacitor electrodes. Previous attempts faced challenges in electrochemical performance due to high charge transfer resistance. To overcome this, we introduce a unique approach, transforming PP masks into high-performance supercapacitor electrodes through thermal carbonization, activation, and fluorination. PVDF annealing fluorination simultaneously executes these transformations, resulting in a 40 % increase in specific capacitance, from 130.4 F g−1 to 183.3 F g−1. Our electrode materials exhibit remarkable durability, retaining an impressive 90.8 % of their initial capacity even after undergoing 8000 charge-discharge cycles, highlighting exceptional electrochemical performance. The porosity of the fluorinated carbon fibers (FCF) was determined through N2 adsorption at 77 K, revealing a pore volume of 0.5 cm3 g−1 and a specific surface area of 1175 m2 g−1. This study not only repurposes PP from masks but also enhances their electrochemical properties, addressing environmental impact and representing a significant stride in sustainable material development.

One-Pot Facile Synthesis of a Cluster of ZnS Low-Dimensional Nanoparticles for High-Performance Supercapacitor Electrodes.

To maximize the use of ZnS low-dimensional nanoparticles as high-performance supercapacitor electrodes, this work describes a simple one-pot synthesis method for producing a cluster of these particles. The ZnS nanoparticles fabricated in this work exhibit a cluster with unique low-dimensional (0D, 1D, and 2D) characteristics. Structural, morphological, and electrochemical investigations are all part of the thorough characterization of the produced materials. An X-ray diffraction pattern of clustered ZnS nanoparticles reflects the phase formation with highly stable cubic blende sphalerite polymorph. The confirmation of nanoparticle cluster formation featuring multiple low-dimensional nanostructures was achieved through field emission scanning electron microscopy (FE-SEM), while the internal structure was assessed using transmission electron microscopy (TEM). Systematically assessing the ZnS nanoparticles' electrochemical performance reveals their prospective qualities as supercapacitor electrode materials. The electrode assembled with this material on Ni foam demonstrates elevated specific capacitance (areal capacitance) values, reaching 716.8 F.g⁻1 (2150.4 mF.cm-2) at a current density of 3 mA.cm⁻2. Moreover, it reflects 69.1% capacitance retention with a four times increase in current density, i.e., 495.5 F.g-1 (1486.56 mF.cm-2) capacitance was archived at 12 mA.cm-2 with 100% Coulombic efficiency. Furthermore, the electrode exhibits prolonged cycling capability with 77.7% capacitance retention, as evidenced by its charge-discharge measurements sustained over 15,000 cycles at a current density of 25 mA cm⁻2.

Nitrogen-doped hollow carbon spheres decorated with NiCo alloy nanoparticles for high-performance supercapacitor electrode

Nitrogen-doped hollow carbon spheres (NHCSs) decorated with NiCo alloy nanoparticles (NPs) were prepared and examined for their prospective role as high-performance electrode materials. The NHCSs were synthesized through a silica-assisted synthesis method, followed by the decoration of NiCo alloy NPs onto the NHCSs using a simple wet impregnation method, employing a 1:1 M ratio of Co to Ni elements. The NiCo/NHCS-23, composed of NHCSs with 23 wt% of NiCo alloy NPs, exhibited a specific capacitance (Csp) of 536 F g−1 when tested in a 6 M KOH solution at a current density of 1 A g−1. This high Csp is attributed to the synergistic effect of the faradaic charge storage provided by NiCo alloy NPs and the N-doped hollow carbon structure. The N content of the NHCSs and NiCo/NHCS-23 was found to be 1.9 % and 2.2 %, respectively. Symmetric supercapacitor (SSC) devices were assembled using two NiCo/NHCS-23 electrodes and a 0.5 M tetraethylammonium tetrafluoroborate/propylene carbonate electrolyte. The resulting SSC device operated within a potential window of 3.5 V and exhibited an energy density of 16.1 Wh kg−1 at the power density of 250 W kg−1. The SSC device demonstrated impressive cycling stability, maintaining 90.0 % capacitance and 83.1 % Coulombic efficiency after 5000 cycles. These results suggest that NiCo/NHCS nanocomposites have significant potential for utilization in high-energy storage applications.

Synthesis of high-performance supercapacitor electrode materials by hydrothermal route based on ZnSe/MnSe composite

The energy crises have emerged in the contemporary period due to the rapid expansion of industry. The expansion of high-capacity storage systems that can operate independently and use renewable energy is essential. The pseudocapacitors are known for their excellent anode properties, which contribute to high specific capacitance (Cs). Transition metal selenide (TMS) has arisen as a highly promising choice for anode materials in supercapacitor (SCs) devices, owing to its noteworthy conductivity and storage capacity. In the current investigation, the simple hydrothermal approach was utilized to achieve the successful synthesis of the binary ZnSe@MnSe (ZS@MS) composite for electrode material. However, crystallinity of ZS@MS composite indicates its potential for utilization as an electrode in supercapacitor (SCs) applications. Moreover, ZS@MS electrode revealed remarkable specific capacitance (Cs) of 1439.98 F g−1 in electrochemical performance. In addition, ZS@MS electrode exhibits a high energy density (Ed) of 56.17 Wh kg−1 and power density (Pd) 265 W kg−1 at 1 A g−1. Moreover, ZS@MS electrode demonstrates stable behavior and exceptional cyclic stability over 5000th cycles. Fabricated ZS@MS electrode material possesses more electrochemical properties than pure materials, making it highly promising for supercapacitors (SCs) and other energy storage-related applications.

Porous 3D honeycomb structures formed from interconnected Ni(OH2) sheets on CNT-coated hybrid framework as high-performance electrodes for supercapacitors

Here, we report the effective hydrothermal synthesis of nickel hydroxide [Ni(OH)2] nanomaterials with a honeycomb-like structure comprising two-dimensional (2D) nanoplates formed from nanosheet arrays. According to the powder X-ray diffraction data, a composite consisting of Ni(OH)2 and carbon nanotubes was effectively created. The presence of significant vibrations of CNT and Ni(OH)2 was verified by FTIR and Raman spectra. Elements in the synthesized composite were validated by energy-dispersive X-ray analysis, and experimental and theoretical values agreed well. Specific capacitance of 1715 Fg−1 at 1 Ag−1 was attained with novel Ni(OH)2 designs incorporated over CNT Ni foam. The effectiveness of the honeycomb Ni(OH)2@CNT network device is equivalent to that of existing carbon-based and metal oxide/carbon-based solid-state supercapacitor devices, with a maximum energy density of 77.2 Whkg−1 and a power density as high as 866 Wkg−1. In particular, after 10,000 cycles, this material retains a large percentage of its original capacitance (94.4 % to be exact) while still maintaining a respectable Coulombic efficiency (84.5 %). These encouraging findings suggest these materials might be used in efficient, cheap, and safe energy storage systems.

Sweet Side Streams: Sugar Beet Pulp as Source for High-Performance Supercapacitor Electrodes.

Valorization of the lignocellulosic side and waste streams is key to making industrial processes more efficient from both an economic and ecological perspective. Currently, the production of sugars from beets results in pulps in large quantities. However, there is a lack of promising opportunities for upcycling these materials despite their promising properties. Here, we investigate beet pulps from two different stages of the sugar manufacturing process as raw materials for supercapacitor electrodes. We demonstrate that these materials can be efficiently converted to activated, highly porous carbons. The carbons exhibit pore dimensions approaching the size of the desolvated K+ and SO42- ions with surface areas up to 2600 m2 g-1. These carbons were subsequently manufactured into electrodes, assembled in supercapacitors, and tested with environmentally friendly aqueous electrolytes (6 M KOH and 1 M H2SO4). Further analysis demonstrated the presence of capacitance-enhancing functionalities, and up to 193 and 177 F g-1 in H2SO4 and KOH, respectively, were achieved, which outperformed supercapacitors prepared from commercial YP80 F. Overall, our study suggests that side streams from sugar manufacturing offer a hidden potential for use in high-performance energy storage devices.

Self-assembled high polypyrrole loading flexible paper-based electrodes for high-performance supercapacitors

Despite the intriguing features of freestanding flexible electronic devices, such as their binder-free nature and cost-effectiveness, the limited loading capacity of active material poses a challenge to achieving practical high-performance flexible electrodes. We propose a novel approach that integrates multiple self-assembly and in-situ polymerization techniques to fabricate a high-loading paper-based flexible electrode (MXene/Polypyrrole/Paper) with exceptional areal capacitance. The approach enables polypyrrole to form a porous conductive network structure on the surface of paper fiber through MXene grafting via hydrogen bonding and electrostatic interaction, resulting in an exceptionally high polypyrrole loading of 10.0 mg/cm2 and a conductivity of 2.03 S/cm. Moreover, MXene-modified polypyrrole paper exhibits a more homogeneous pore size distribution ranging from 5 to 50 μm and an increased specific surface area of 3.11 m2/g. Additionally, we have optimized in-situ polymerization cycles for paper-based supercapacitors, resulting in a remarkable areal capacitance of 2316 mF/cm2 (at 2 mA/cm2). The capacitance retention rate and conductivity rate maintain over 90 % after undergoing 100 bends.The maximum energy density and cycling stability are characterized to be 83.6 μWh/cm2 and up to 96 % retention after 10,000 cycles. These results significantly outperform those previously reported for paper-based counterparts. Overall, our work presents a facile and versatile strategy for assembling high-loading, paper-based flexible supercapacitors network architecture that can be employed in developing large-scale energy storage devices.

Porous Mn2O3 nanorods-based electrode for high-performance electrochemical supercapacitor

In this research, we introduce an effective electrode material, i.e. porous manganese oxide (Mn2O3) nanorods (NRs) prepared by simple hydrothermal process, designed for use in electrochemical supercapacitors. XRD analysis unequivocally confirms that the Mn2O3 NRs possess a pure cubic crystalline structure with an Ia3 space group, indicating the high degree of crystallinity and phase purity. Morphological examinations confirmed that the Mn2O3 NRs display a distinct rod-like structure, featuring an average size of around 30 nm, underscoring their nanostructured characteristics. The electrochemical performance of the synthesized Mn2O3 NRs as electrodes for supercapacitors was thoroughly examined, resulting in an impressive specific capacitance of 483 F/g at a scan rate of 10 mV/s. Electrochemical impedance spectroscopy (EIS) analysis was carried out to assess the effective series resistance (ESR), revealing a minimal resistance value of 3.2 Ω, highlighting excellent charge transfer kinetics. Mn2O3 NRs electrode displayed exceptional capacitance retention even after undergoing 500 charge–discharge cycles at a high current density of 5 A/g, indicating their remarkable chemical stability as an electrode material. This study introduces a promising and scalable approach for the development of high-performance supercapacitors, with Mn2O3 NRs as a critical component, and offers valuable insights into the design and engineering of advanced energy storage devices.

Nickel-cobalt layer double hydroxide @ lignin-based hollow carbon quasi core-shell structure for high-performance supercapacitors

The physicochemical properties of an advanced supercapacitor electrode material can be co-tailored by incorporating various active materials into a hierarchical micro-/nano-architecture with a core-shell structure. Herein, we presented the development of high-performance supercapacitor electrode materials of quasi core-shell architectures based on nickel-cobalt layered double hydroxides supported on lignin-based hollow carbon (NiCoLDH@LHC) nanocomposites. The synthesis involves a novel approach combining enzymatic hydrolysis lignin (EHL) as a carbon source and magnesium oxide (MgO) as a template, utilizing evaporation-induced self-assembly (EISA) followed by carbonization. The manipulation of the mass ratio of NiCoLDH/LHC can induce alterations in its apparent morphology, stratified porosity, and active site, thereby an influence on its electrochemical performance. The optimal NiCoLDH@LHC90 nanocomposites display a unique flower-like spherical structure with open pores, a substantial specific surface area (SSA), and numerous electrochemically active sites. In addition, the density functional theory (DFT) calculations demonstrate that the higher density of Ni3+/Co3+ cations induced by the incorporation of LHC can increase the conductivity of NiCoLDH materials. Notably, these nanocomposites exhibit a remarkable specific capacitance of up to 640 C g−1 at 1 A g−1, with exceptional cycling stability (93.66% retention over 10,000 cycles). Furthermore, an assembled NiCoLDH@LHC90//LHC asymmetric supercapacitor demonstrates an impressive energy density (power density) of 35.44 Wh kg−1 (200.01 W kg−1). The physicochemical properties of an advanced supercapacitor electrode material can be finely tuned by incorporating various active materials into a hierarchical micro-/nano-architecture with a core-shell structure.

Mn-doped nickel–cobalt sulfides as bifunctional electrodes for high-performance supercapacitors and electrocatalysts for hydrogen evolution reactions

The development of active electrode materials with dual functions of energy storage and electrocatalyst is important for future energy storage and energy conversion devices. In this work, manganese-doped nickel cobalt sulfide (Mn-NCS) mesoporous microspheres were prepared via a simple two-step solvent-thermal method and the effects of different Mn2+ doping levels on the electrochemical properties and hydrogen evolution reactions (HER) of the prepared samples were investigated. As a supercapacitor electrode material, optimized Mn0.5-NCS had a maximum specific capacitance of 1175 C g−1 at a current density of 1 A/g and remained an outstanding capacitance retention rate of 81 % at a current density of 20 A/g. The asymmetric supercapacitor was assembled with the optimal electrode material as the positive electrode and activated carbon as the negative electrode, and a high energy density of 55.4Wh kg−1 was achieved at a power density of 797 W kg−1. The Mn0.5-NCS exhibited the best HER performance in alkaline electrolyte, shown as the lowest overpotential of 95 mV and the smallest Tafel slope of 71 mV dec−1 at a current density of 10 mA cm−2. Experimental tests and density functional theory (DFT) calculations revealed that manganese preferentially occupies nickel sites and acted as an electron donor in the electrochemical process to realize the electron redistribution, increasing electron density and accelerating charge transfer. The results indicated that manganese-doped nickel–cobalt sulfides have great potential as bifunctional electrode materials for high-performance supercapacitors and HER.

Preparation of NiMoO4 porous nanosheets by freezing method as adhesive-free electrodes for high-performance flexible supercapacitors

Preparation of NiMoO4 porous nanosheets by freezing method as adhesive-free electrodes for high-performance flexible supercapacitors

Fabrication of Polypyrrole/Reduced Graphene Oxide/Silk as a High-Performance Electrode for Fiber-Shaped Flexible Supercapacitor

Fabrication of Polypyrrole/Reduced Graphene Oxide/Silk as a High-Performance Electrode for Fiber-Shaped Flexible Supercapacitor

Loofah sponge-derived 3D flexible porous carbon electrode for high performance supercapacitor

Energy storage facilitate the substitution of clean and sustainable new energy including solar, wind and tidy energy to the pollution-produced and one-off conventional fossil. Carbon, as activated material, plays key roles in both supercapacitor and battery. Biomass-derived carbon makes fossil-free energy storage be realized. Herein, natural loofah sponge is chosen as the carbon source in supercapacitor. Based on the special network and macroscopical shape of loofah, 3D porous carbon electrode rather than powdery activated material is directly constructed. Especially, flexibility is endowed to this carbon electrode when the lignin and hemicellulose are selectively removed. 3D flexible carbon electrode prepared at the optimized conditions (FLSC-4-1000) owns a high specific surface area of 772.87 m2 g−1. In addition, FLSC-4-1000 exhibits outstanding electrochemical supercapacitor performance: A specific capacitance of 267 F g−1 at the current density of 0.5 A g−1 and a high capacitance retention of 97 % over 10,000 cycles for the electrode. Meanwhile, an energy density of 20.35 Wh kg−1 at 900 W kg−1 and 18.5 Wh kg−1 at 18.01 kW kg−1 for symmetric supercapacitor (SSC) of FLSC-4-1000//FLSC-4-1000.

Binder-free V-doped CrN thin film electrode enables high performance symmetric supercapacitor

Transition metal nitrides (TMNs) are rapidly gaining prominence as attractive supercapacitor electrode materials due to their intriguing properties. Nevertheless, the quest for facile and green fabrication of TMNs electrodes with high supercapacitor performance remains a substantial challenge. In this study, we have successfully designed and prepared the binder-free V-doped CrN thin film electrodes through a one-step reactive magnetron co-sputtering in nitrogen and argon atmosphere without high temperature heating. Our experimental and DFT findings confirm that the V doping increases the number of active sites, enlarges the specific surface area, and enhances the electron concentration and electrical conductivity. Consequently, the CrVN thin film electrodes achieve a remarkable specific capacitance of 22.8 mF cm−2 at 1.0 mA cm−2, along with excellent cycling performance (93.9% capacitance retention after 20,000 cycles at 5.0 mA cm−2). Furthermore, the assembled CrVN symmetric supercapacitor device exhibits a substantial energy density of 11.2 mWh cm−3 and an impressive power density of 7.5 W cm−3, respectively. These encouraging outcomes open new avenues for developing ternary TMNs-based electrodes for high performance supercapacitors.