Search

[Display omitted] • The polyhedral-shaped CdS decorated ZIF-8 nanocomposites have been prepared by in-situ synthesis. • It exhibits good cyclic stability, with 85.91 % (RAE) capacity retention after 6000 cycles at 5 A/g. • CdS@ZIF-8 achieves a specific capacitance of 1065 Fg−1 at 5 mV/s. With reference to the promising characteristics of metal–organic frameworks (MOFs) and the contributions of nanoparticles (NPs) to their electrochemical activities, the hybrid MOF built with metal sulphides has garnered a lot of attention, primarily as electrode materials in energy storage devices. The polyhedral-shaped CdS enwrapped zeolitic imidazolate framework-8 (ZIF-8) nanocomposites have been prepared by in-situ chemical synthesis. The electrochemical performance was evaluated in 6 M KOH electrolyte, achieving a specific capacitance of 1063.48 Fg−1 at 5 mV/s. The nanocomposite electrode material exhibits good cyclic stability, with 82.32 % (6 M KOH) and 85.91 % (redox additive electrolyte) capacity retention after 6000 cycles at 5 A/g. The energy and power density of the asymmetric supercapacitor were found to be 2.81 Wh/kg and 1785.71 W/kg, respectively. [ABSTRACT FROM AUTHOR]

[Display omitted] • NiO/Peanut shell activated carbon (Ni/PSAC) using wet impregnation method. • Ni/PSAC electrode delivered a specific capacitance of 848F g−1 at 8 A g−1. • Asymmetric device reporting energy density of 39.14 Wh kg−1. • For waste-to-effective energy storage, it is an excellent strategy. The approach outlined in this study provides insights into developing sustainable and cost-effective energy storage solutions utilizing agricultural waste materials focusing on using peanut shells to make activated carbon with subsequent impregnation of NiO for supercapacitor electrodes. X-ray diffraction analysis showed the NiO-impregnated peanut shell-activated carbon (Ni/PSAC) nanocomposite material had a face-centered cubic structure. The electrochemical behavior of Ni/PSAC electrode and Ni/PSAC//AC device were comprehensively deliberated through cyclic voltammetry (CV), Galvanostatic charge–discharge (GCD), and electrochemical impedance spectroscopy (EIS) techniques. The GCD data of Ni/PSAC//AC device uncovered a boosted specific capacitance of 154.63F g−1, accompanied by an energy density of 39.14 Wh kg−1 and a power density of 2700 W kg−1 at 2 A g−1 current density. These findings suggest the potential of mesoporous Ni/PSAC electrode as an efficient and hopped-up material for asymmetric supercapacitor. [ABSTRACT FROM AUTHOR]

[Display omitted] • Self-O-doped Alpinia galanga stem-based carbon nanofiber succesfully synthesis. • The hierarchical porous carbon exhibit high specific surface area of 1065.58 m2/g. • The porous carbon was performed in solid-free binder form. • In 2-electrode system, supercapacitor possessed specific capacitance of 226F g−1. In this study, activated carbon with hierarchical pores and a nanofiber structure doped with oxygen was prepared using a pure biomass-based sustainable strategy involving integrated chemical impregnation and pyrolysis. Alpinia galangal stem was chosen as it functions as fast conductive network with abundant electrochemical active sites for high-grade electrode materials. The optimal precursor exhibited self-doping of oxygen ranging from 6.15 to 15.69 % with 1065.58 m2/g, which contributed to the redox reaction of the electrode material. When tested in a 2-electrode system, the porous carbon nanofibers showed a high specific capacitance of 226F g−1 at 1 A g−1 in 1 M H 2 SO 4 electrolyte, producing an energy density of 9.3483 Wh kg−1 with a coulombic efficiency of 89.01 %. The results showed that oxygen-doped hierarchical porous carbon nanofibers produced from Alpinia galangal stem biomass and designed to be solid-free of binders are highly promising as high-quality electrode materials that can improve sustainable supercapacitor performance. [ABSTRACT FROM AUTHOR]

• Sulfur-rich WS 2 /WO 3 electrodes reached a specific capacitance of 570.1 F/g. • Battery-type behavior in WS 2 /WO 3 electrodes was identified using power law. • WS 2 /WO 3 //AC device revealed energy and power density of 55.6 Wh/kg and 1335 W/kg. • Capacitance retention and columbic efficiency were 87.4% and 99.8% for 5000 cycles. Active sites enriched WS 2 quantum dot decorated WO 3 electrode was designed for supercapacitor application, using hydrothermal and sonication techniques. The WS 2 /WO 3 electrode exhibited a specific capacitance of 570.1 F/g at 1 A/g due to numerous active sites, and facile electrolyte accessibility. The battery-type WS 2 /WO 3 //AC asymmetric supercapacitor device achieved an energy and power density of 55.6 Wh/kg and 1335 W/kg, and a notable retention capacitance and columbic efficiency of 87.4 % and 99.8 % for 5000 cycles at 6A/g, respectively. The results highlight WS 2 /WO 3 as a promising electrode for supercapacitors. [ABSTRACT FROM AUTHOR]

N-doped hierarchical porous carbon as an excellent electrode material in symmetric supercapacitor is fabricated by a facile and green method. [Display omitted] • N-doped porous carbon is prepared from one-step pyrolysis of glycine and Na 2 CO 3. • It exhibits a high capacitance of 207 F/g at 20 A/g in a symmetric supercapacitor. • 99.95% of initial capacitance remains after 10,000 cycles at 5 A/g. • A high energy density of 28.8 Wh/kg is obtained at a power density of 20 KW/kg. N-doped hierarchical porous carbon (NHPC) was facilely fabricated by a one-step pyrolysis of glycine and water-soluble Na 2 CO 3 , which is employed as a renewable water-soluble template without additional corrosive activating reagent. Benefiting from the hierarchical porous structure, high specific surface area (2735 m2 g−1) and the suitable nitrogen content of 3.84 at%, the obtained porous carbon exhibits a high specific capacitance (C sp) of 267 F g−1 at 0.2 A g−1 in a three-electrode system and 201 F g−1 at 0.2 A g−1 in the symmetric supercapacitor. More importantly, it shows an impressive rate capability of 102 % retention at 20 A g−1, outstanding cycling stability with 99.95 % of capacitance retention at 5 A g−1 after 10,000 cycles and a high energy density of 28.8 Wh kg−1 at a power density of 20 KW kg−1 in the symmetric supercapacitor. The results indicate that the synthesized NHPC obtained from this simple synthesis method would be an effective electrode material for symmetric supercapacitors, and this eco-friendly and easily scaled-up approach would provide a valuable strategy for the synthesis of porous carbon materials. [ABSTRACT FROM AUTHOR]

• Tubular Cu 2 MoS 4 /MWCNTs were prepared as supercapacitor negative electrode material. • Appropriate MWCNTs addition significantly optimized the electrochemical performance. • CMS/MWCNTs-0.15@CC exhibits a highest specific capacitance of 219F g−1 at 0.5 A g−1. • The device with a voltage window of 1.8 V yields an energy density of 24.5 Wh kg−1 at 900 W kg−1. The ternary layered Cu 2 MoS 4 (CMS) has been proven to be a potential supercapacitor negative electrode material. However, its inherent low conductivity and limited diffusion dynamics usually result in unsatisfactory specific capacitance and rate performance. Therefore, hollow tubular CMS and CMS/MWCNTs-0.05, 0.15, 0.25 composite materials were prepared by a one-pot hydrothermal method in this work. The addition of MWCNTs improves the electrical conductivity and provides an efficient three-dimensional electronic transport network. Due to the smallest resistance and optimized porous structure with large surface area, CMS/MWCNTs-0.15@CC exhibits a highest specific capacitance (C s) of 219F g−1 at 0.5 A g−1, which is 2.45 times that of CMS@CC. The assembled Ni-Co-S@CC//CMS/MWCNTs-0.15@CC supercapacitor with a voltage window of 1.8 V yields a maximum energy density of 24.5 Wh kg−1 at 900 W kg−1. [ABSTRACT FROM AUTHOR]

• Et additive could effectively expand ESW of EC from 1.8 to 2.1 V. • EC show an improved energy density with Et additive. • Et additive display many advantages of low cost, high safety. Due to the advantages of high safety, high conductivity and low cost, the supercapacitor with aqueous electrolytes exhibits the great prospects in the future energy storage market. However, the narrow electrochemical stability window (ESW) of electric double-layer supercapacitor leads to its low energy density, which seriously limits its application. Herein, we demonstrate erythritol (Et) additive could efficaciously decrease the water molecules in the solvation sheath and break the hydrogen bond network of aqueous electrolytes, which resulting in expanded ESW. Especially, symmetric supercapacitor based on 37.9% Et additive to 1 M LiTFSI electrolyte expands ESW from 1.8 to 2.1 V, and the energy density increased to 13.3 Wh kg−1 with high specific capacitance of 86.6F g−1 and the capacitance retention rate of 73.8% after 10,000 cycles. Therefore, this study affords an efficient strategy to achieve high energy density aqueous supercapacitor. [ABSTRACT FROM AUTHOR]

• 2D Mxene-Ti 3 C 2 intercalated ZnCo 2 O 4 nanowires have been successfully synthesized. • The introduction of Ti 3 C 2 accelerates the dynamics of electrochemical reactions. • An ASC exhibits high energy density and 90.5% capacity retention after 10,000 cycles. It is necessary to develop hierarchical structured materials with excellent electrochemical characteristics and stability for energy storage. In this work, we synthesize a novel structure of ZnCo 2 O 4 /Ti 3 C 2 on Ni foam by a simple hydrothermal method. The frameworks accelerates the kinetic of the electrochemical reaction and promotes the transfer of electrons. The cycling stability of the device maintains 108.2% after 4000 cycles. The result indicates that the prepared sample is an excellent candidate material for energy storage. [ABSTRACT FROM AUTHOR]

[Display omitted] • NGO/NiWO 3 /PANI nanocomposite was prepared by Hydrothermal method. • Current density of NGO/NiWO 3 /PANI electrode is significantly increased. • Specific capacitance of NGO/NiWO 3 /PANI electrode is about ∼1380 F/g at 0.5 A/g. • NGO/NiWO 3 /PANI electrode material displays excellent cycling stability. Hybrid supercapacitors signify a potential candidate for highly stable energy storage devices because of their excellent power density, low cost, and inherent safety. Hydrothermal method was used to synthesize NGO (Nitrogen doped graphene oxide)/NiWO 3 (nickel tungstate)/PANI (polyaniline)) nanocomposite (NC). GCD analysis offers noticeable enhanced specific capacitance of 1380 F/g as compared to NiWO 3 (670 F/g) and displays the cycle stability for 10 000 cycles with 92.6 % retention of capacitance at the current density of 0.5 A/g, and also shows a high energy density of 47.8 W h kg−1. These obtainable outcomes propose that NGO/NiWO 3 /PANI can be considered an efficient electrode for highly stable supercapacitors. [ABSTRACT FROM AUTHOR]

• The NiCoS@NiMo-LDH hierarchical composites are synthesized on Ni foam. • NiCoS@NiMo-LDH nanostructure provides abundant active sites and enough ion channels. • The binder-free NiCoS@NiMo-LDH electrode exhibits excellent electrochemical properties. • The fabricated ASC device exhibits a high energy density and good stability. Ni(OH) 2 ·0.75H 2 O nanosheets embedded with NiMoO 4 nanoparticles (NiMo-LDH) supported by nickel cobalt sulfur (NiCoS) nanorods were prepared by a multi-step hydrothermal method, which provides an effective channel for ion transport and abundant active sites for charge storage. The NiCoS@NiMo-LDH electrode exhibited a very high capacitance of 1302.5 μAh cm−2 at 10 mA cm−2, with 54 % capacitance retention observed at 50 mA cm−2. The asymmetric supercapacitor (ASC) assembled with the NiCoS@NiMo-LDH as the positive electrode and active carbon (AC) as the negative electrodes which exhibits an energy density of 1096.6 μWh cm−2 at a power density of 2.8 mW cm−2 along with good stability of 86.67 % after 5000 cycles. [ABSTRACT FROM AUTHOR]

• Fe 3 O 4 /C was synthesized for the supercapacitor with expired ferrous gluconate as the precursor; • Fe 3 O 4 /C powder appeared as the hierarchical dumbbell-like morphology; • The capacitances of three-electrode and two-electrode systems were 490.2F/g and 210.2F/g; • The unique hierarchical dumbbell-like morphology was responsible for high capacitances; • The desirable results indicated high feasibility of the circular economy of the wastes. Hierarchical dumbbell-like Fe 3 O 4 /C powder was synthesized for the supercapacitor electrode by the solvothermal reaction and subsequent calcination. Resultantly, the reversible capacitances of the three-electrode and symmetric two-electrode capacitors were 490.2 F/g and 210.2 F/g, respectively, higher than those in literatures, possibly due to the unique hierarchical dumbbell-like structure with the easier access and penetration of the electrolyte to the electrode. Moreover, the symmetric Fe 3 O 4 /C two-electrode system exhibited the remarkable cycle stability at 5.0 A/g and high energy density of 34.3 Wh/kg at 1003.9 W/kg, indicating high feasibility for the application in high-performance supercapacitor. [ABSTRACT FROM AUTHOR]

[Display omitted] • The Co 3 O 4 with hexagonal morphology are designed. • Facile synthesis of calcining precursors is prepared the hexagonal Co 3 O 4. • The hexagonal Co 3 O 4 exhibits excellent electrochemical performance. The key to improving the energy density of supercapacitors is to enhance the electrochemical properties of the electrode materials by optimizing the preparation process and rationally designing the material structure. In this work, hexagonal Co 3 O 4 are derived by calcination of the precursors in the air, which are used as electrode materials for high-performance supercapacitors. The specific capacity of the hexagonal Co 3 O 4 electrode reaches 216.4 F g−1 at the current density of 1 A g−1. It is worth mentioning that it achieves a capacity retention rate of 112.5% and a coulombic efficiency of 99.5%, after 10,000 cycles. [ABSTRACT FROM AUTHOR]

In this work, a core/shell structured polypyrrole@manganese dioxide (PPy@MnO 2) composite has been synthesized via one-step in-situ polymerization and subsequent hydrothermal method. [Display omitted] • PPy@MnO 2 with core/shell structure is synthesized via a simple strategy. • MnO 2 is the cross-linked continuous porous nanosheets shell in PPy@MnO 2. • The PPy@MnO 2 exhibits the highest specific capacitance of 614.7F·g−1 at 1.0 A·g−1. • The PPy@MnO 2 //AC device has achieved a satisfied energy density of 34.0 Wh·kg−1. The composition and structure are very critical to the property of electrode materials in supercapacitors. Herein, a core/shell polypyrrole@manganese dioxide (PPy@MnO 2) composite is prepared by a simple strategy. The electrode delivers the C s value of 614.7F·g−1 at 1.0 A·g−1, and exhibits outstanding rate performance in a three-electrode system. Moreover, asymmetric device (PPy@MnO 2 //AC) has been designed and possessed extraordinary rate performance, remarkable cycle stability, and the high energy density of 34.0 Wh·kg−1 at 317.6 W·kg−1. The core/shell structured PPy@MnO 2 delivers the excellent electrochemical performance, indicating its great application potential in supercapacitors. [ABSTRACT FROM AUTHOR]

• MOF-derived porous Co 3 O 4 was obtained. • Simple calcination treatment was used to construct the porous structure. • Nanoporous Co 3 O 4 electrode with high specific capacitance was designed. Supercapacitors with cobalt oxide (Co 3 O 4) electrode are a kind of strong candidates for achieving high-capacity storage energy devices. However, the reported capacitances lower than the theoretical values are undesirable. In this study, a high-performance supercapacitor by using the Co 3 O 4 electrode with a porous nanostructure is enabled by the calcination treatment of metal organic framework ZIF-67. Of note, the resulting Co 3 O 4 electrodes shows high specific capacitance of 1015 F/g under a current density of 1 A/g. Additionally, it exhibits energy density of 36.6 Wh/kg at a power density of 189.5 W/kg and maintains capacitance retention of 78.2% after 5000 cycles at 8 A/g. The strategy proposed here provides a good way to synthesize nanostructured Co 3 O 4 , a candidate for constructing high-capacitance energy storage devices. [ABSTRACT FROM AUTHOR]

The synthesis of holey graphene nanosheets for its use as an efficient electrode material in supercapacitor using green chemistry approach. • A facile approach for green synthesis of holey graphene nanosheets. • Holey graphene nanosheets exhibit highly porous morphology. • Through holes in graphene nanosheets promote cross-plane diffusion. • Holey graphene electrode exhibits efficient capacitive performance (226 F/g). • The fabricated symmetric device retains 93% stability after 5000 cycles. Holey graphene, formed by generating in-plane pores in its basal planes can deliver efficient electrochemical performance due to low resistant pathways and short ion diffusion channels. However, generating holes in graphene's basal planes is a challenging task due to its exceptional mechanical properties which often require toxic and expensive processing methods. In this work, a facile, cost-effective, scalable, and environmentally friendly green approach is adopted to produce holey graphene nanosheets for the supercapacitor application. The fabricated holey graphene electrode exhibits the highest specific capacitance of 226 F/g in the three-electrode system and a specific capacitance of 62 F/g, an energy density of 10.37 Wh/kg, and a power density of 1388 W/kg in the solid-state symmetric device configuration. [ABSTRACT FROM AUTHOR]

• The spherical NiCo 2 O 4 /CuS composites were prepared by hydrothermal method. • The composites possess high specific capacitance. • The composites showed superior high cycling stability. In this work, spherical NiCo 2 O 4 /CuS composites was synthesized by hydrothermal method. As electrode material, it possesses high specific capacitance (2169 F g−1 at 0.5 A g−1), while maintaining excellent stability with about 123% capacitance retention after 7000 cycles at 1 A g−1. The asymmetric supercapacitor based NiCo 2 O 4 /CuS electrode exhibits a high energy density of 173.5 W h kg−1 at at a power density of 360 W kg−1 and can provide power supply for red LEDs indicator. This is mainly attributed to the synergistic effect of CuS and NiCo 2 O 4 , which promotes electron transport and electrolyte ion diffusion. [ABSTRACT FROM AUTHOR]

• The controllable synthesis of nano-hexahedron porous carbon was obtained. • The capacitance retention of nano-hexahedron porous carbon is up to 100% at 5 A g−1 after 10,000 cycles. • The symmetrical supercapacitor exhibits a high energy density of 9.04 Wh kg−1 at a power density of 350 W kg−1. The nano-hexahedron porous carbon was prepared by directly carbonizing a Zn-based zeolitic imidazolate framework (ZIF-8) at designed temperatures. After carbonization, the nano-hexahedron porous carbon shows a large specific surface area of 1142 m2 g−1 at a pore diameter of approximate 3 nm, a high capacitance of 187 F g−1, a remarkable rate-capability of 75.9%, and an unchangeable capacitance retention after 10,000 cycles. Furthermore, the symmetrical supercapacitor exhibits a high energy density of 9.04 Wh kg−1 at a power density of 350 W kg−1 and a notable capacitance retention of 80.2% after 5000 cycles. All results have suggested that the nano-hexahedron porous carbon is adaptable to the assembly of effective electrode materials for supercapacitors. [ABSTRACT FROM AUTHOR]