Search

3D bicontinuous nanoporous copper (NPC) with tunable structure was facilely synthesized by one-step chemical dealloying of Ti-Cu amorphous alloys with minor Co addition (0, 4 and 6 at.%). As-dealloyed NPC shows a sandwich-like hierarchical porous structure with micropore in the inner layer and mesopore in the outer layer. The pore size of NPC can be adjusted by the Co content and corrosion time. In addition, the minor Co element in the matrix alloy can promote the formation of more uniform pore and ligament of NPC, which was evaluated by the surface diffusivity of NPC. The formation mechanism of NPC was discussed using phase separation theory. The NPC/Cu2O composite consists of a large number of 3D continuous ligaments and few tetrahedral Cu2O particles grown on the NPC substrate. As catalysts, NPC/Cu2O composite exhibits excellent degradation performance for methyl orange (MO) dye in the dark assisted by the ultrasonic irradiation due to hierarchical porous structure and the synergistic effect of Cu ligaments and Cu2O particles. The relationship between the efficient MO degradation rate of NPC/Cu2O catalysts and temperature has been discussed. Fenton-like reaction shows that NPC/Cu2O catalysts supplemented with hydrogen peroxide (H2O2) can generate HO· radicals, which resolve MO dye molecules into H2O, CO2 and inorganic species.

Here, mesoporous NiCo2S4 nanosheet fibre‐shaped electrode was prepared using Ni–Co layered double hydroxide (LDH) grown on nickel wire as precursor. NiCo2S4 nanosheet electrode displayed excellent electrochemical properties with specific capacitance of 1974.55 mF/cm2 at 2 mA/cm2 and 86.2% capacitance retention after 5000 cycles, which were far higher than those of Ni‐Co LDH precursor. Our work provides new strategy to improve the performance of LDH used for supercapacitor.

The present study explores the antecedents of frontline employees’ boundary-spanning behaviors in the hospitality industry. Based on social exchange theory and role theory, a conceptual model was b...

Transition metal phosphides (TMPs) are a hopeful noble-metal-free catalysts for water splitting. In this study, we used a three-dimensional nanostructure on nickel substrate to easily synthesize a nickel–cobalt phosphide electrocatalyst (NixCoyP, x = 1, 1.5, 2; y = 1, 1.5, 2) through hydrothermal reaction and in situ phosphorylation. The NiCo1.5 P exhibited relatively excellent oxygen evolution activity performance, and it only needed the overpotentials of 123 mV for HER in 1 M KOH to perform the current densities of 10 mA cm−2. It is worth mentioning that the Ni2CoP exhibited better bifunctional electrocatalyst characteristics. As to water splitting, the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) require 197 and 253 mV overpotentials separately to provide a current density of 10 mA cm−2. Its relatively excellent electrochemical performance can be ascribed to the high-density sea urchin-like three-dimensional structure, which provides greater specific surface area and more active site. Besides, Ni2CoP also shows long-term durability lasting 80,000 s, and on this basis, there is no distinct deactivation. This work emphasizes that Ni2P and CoP play a vital role relative to the good activity of HER. Moreover, the unique morphology with self-supported structure provides a larger specific surface area, making it possible the exposure of higher amount of active sites for HER. These self-supported electrocatalysts that do not require a binder could also make the electrode more active and stable. This work, therefore, presents a strategy that is controllable and feasible strategy for the synthesis of bimetallic phosphides with unique morphology and high HER and OER activity.

Functionalized carbon nanomaterials are potential candidates for use as anode materials in potassium-ion batteries (PIBs). The inevitable defect sites in the architectures significantly affect the physicochemical properties of the carbon nanomaterials, thus defect engineering has recently become a vital research area for carbon-based electrodes. However, one of the major issues holding back its further development is the lack of a complete understanding of the effects accounting for the potassium (K) storage of different carbon defects, which have remained elusive. Owing to pressing research demands, the construction strategies, adsorption difficulties, and structure-activity relationships of the carbon defect-involved reaction centers for the K adsorption are systematically summarized using first principles calculations. Carbon defects affect the ability to trap K by affecting the geometry, charge distribution, and conductive behavior of the carbon surface. The results show that carbon doping with pyridinic-N, pyrrolic-N, and P defect sites tend to act as trapping K sites because of electron-deficient sites. However, graphite-N and sulfur doping are less capable of trapping K. In addition, it has been proved using calculations that the defects can inhibit the growth of the K dendrite. Finally, using the molten salt method, we prepared the undoped and nitrogen-doped carbon materials for comparison, verifying the results of the calculation.

Transition-metal phosphates/phosphides, as an emerging kind of prominent electroactive material, have drawn extensive attention in the fields of energy conversion and storage owing to their high el...

Potassium-ion capacitors (PICs) have drawn appreciable attention because PICs can masterly integrate the virtues of the high energy density of battery-type anode and high power density of capacitor-type cathode. However, the sanguine scenario involves the incompatible capacity and sluggish kinetics in the PIC device. Herein, we report the synthesis of nitrogen and phosphorus-doped network porous carbon materials (NPMCs)

In the present paper, starch was used as raw material to prepare carbon material with low-temperature hydrothermal route and hierarchical three-dimensional cross-linked porous carbon was successfully synthesized with the help of a small amount of graphene for high-performance supercapacitors. It's found that presence of graphene is a crucial condition for the formation of 3D porous carbon and graphene acts as a skeleton in the porous carbon. This kind of carbon material exhibited very high surface area of 1887.8 m2 g−1 and delivered excellent electrochemical performance. Its specific capacitance can reach 141 F g−1 at 0.5 A g−1 and more importantly, after 10,000 cycles 98.6% of initial specific capacitance can be maintained. To explore the practical application of the 3D porous carbon, an asymmetric supercapacitor coin-type device was assembled with 3D porous carbon and graphene as electrode materials in organic electrolyte. The constructed device exhibited high energy density of 48.5 Wh·kg−1 at a power density of 1.5 kW kg−1 and still maintains 39.625 Wh·kg−1 under the high power density (15 kW kg−1). These results will promote the rapid development of 3D porous carbon prepared by low-temperature route and the application in supercapacitors.

Flexible wire-shaped supercapacitors have attracted wide interest due to the increasing demand for portable and wearable electronics. Due to the complex functioning atmosphere of wearable electronics, their mechanical stability and electrochemical stability under different bending states are required. In this work, the self-made Ag-coated cotton wire was adopted as the collector and zinc–cobalt layered double hydroxide nanosheets were successfully electrodeposited on this wire (Ag-CW@ZnCo-LDH) by a facile chronopotentiometry with a constant current of 0.02A. Ag-CW@ZnCo-LDH electrode displayed a high specific capacitance of 1732.4 F g−1 at 1 A g−1 and 61.7% of capacitance retention after 2000 cycles at 10 A g−1. Flexible wire-shaped symmetric supercapacitor was fabricated by two same Ag-CW@ZnCo-LDH electrodes, which exhibited a working potential window of 1.2 V. The as-assembled WSSC showed a good electrochemical performance with specific capacitance of 16.3 F g−1 and energy density of 1.33 Wh kg−1 at power density of 1224 W kg−1. In addition, its CV curves barely deviated at all bending angles, manifesting the outstanding mechanical stability and great potential for practical application.

Flake-like NiCo bimetal-organic framework (NiCo-MOF) is prepared via a simple one-step hydrothermal process. By combining the advantages of composition designing and distinctive micro/nanostructures, the flake-like NiCo-MOF constructed with two-dimensional (2D) nanosheets can be a promising candidate as active material for high-performance supercapacitors (SCs) in the aspect of enhanced specific capacitance and stability. In a three-electrode system using 1 m KOH as electrolyte, the fabricated flake-like NiCo-MOF electrode exhibits high-specific capacitance (1107.3 F g− 1 at 1 A g− 1), good rate performance (76.7% retention of its highest capacitance at 10 A g− 1) and long-term cycling stability (70.1% capacity retention after 5000 cycles at 15 A g− 1). Furthermore, an energy storage device based on reduced graphene oxide and flake-like NiCo-MOF shows a maximum energy density of 30.81 Wh kg− 1 at a power density of 749.9 W kg− 1 with high capacitance retention of ~ 85.3% (up to 5000 cycles at 15 A g− 1).

Nickel sulfide-based materials have shown great potential for electrode fabrication owing to their high theoretical specific capacitance but poor conductivity and morphological aggregation. A feasible strategy is to design hybrid structure by introducing highly-conductive porous carbon as the supporting matrix. Herein, we synthesized hybrid composites consisting of interconnected NiS-nanosheets and porous carbon (NiS@C) derived from Zeolitic-imidazolate frameworks (ZIFs) using a facile low-temperature water-bath method. When employed as electrode materials, the as-prepared NiS@C nanocomposites present remarkable electrochemical performance owing to the complex effect that is the combined advantages of double-layer capacitor-type porous carbon and pseudocapacitor-type interconnected-NiS nanosheets. Specifically, the NiS@C nanocomposites exhibit a high specific capacitance of 1827 F g−1 at 1 A g−1, and excellent cyclic stability with a capacity retention of 72% at a very high current density of 20 A g−1 after 5000 cycles. Moreover, the fabricated hybrid supercapacitor delivers 21.6 Wh kg−1 at 400 W kg−1 with coulombic efficiency of 93.9%, and reaches 10.8 Wh kg−1 at a high power density of 8000 W kg−1, along with excellent cyclic stability of 84% at 5 A g−1 after 5000 cycles. All results suggest that NiS@C nanocomposites are applicable to high-performance electrodes in hybrid supercapacitors and other energy-storage device applications.

In this work, NiSe@Ni3S2 core-shell composite material was prepared with Ni foam as a substrate. Due to their unique structure, the NiSe@Ni3S2 composite shows a superior specific capacitance of 1215 F g−1, which is better than pure NiSe. Meanwhile, the NiSe@Ni3S2 electrode demonstrates a wonderful cycling performance with 91.25% retention after 5000 cycles. The positive electrode materials and the negative electrode materials were designed employing the asymmetric supercapacitor (ASC) and the activated carbon (AC), respectively (ASC was created using NiSe@Ni3S2 composite).When the optimal potential window of 1.8 V and the power density of 839 W kg−1, the maximum energy density of 38 W h kg−1 was reached. In addition, after 5000 charge-discharge cycles, the NiSe@Ni3S2/NF//AC ASC devices exhibit a favorable cycling performance of 81.8% capacitance retention. These outstanding electrochemical performances demonstrate feasible testimony to verify that the NiSe@Ni3S2 composite shows unlimited latent force at the research field of energy storage devices in the future.

Three-dimensional bicontinuous nanoporous copper (NPC) with a pore size of 10–60 nm was fabricated by dealloying titanium–copper–cobalt amorphous ribbons in 0.23 M hydrofluoric acid (HF) solution for 1–12 h. It is found that dealloyed ribbons show sandwich-like layered structure in the cross-section and the pore size in the outer layer is larger than that in the core layer. The NPC ribbons, polarised in 1 M potassium hydroxide (KOH) solution for 30 min, delivered an excellent electrochemical performance with a specific capacitance of 202.3 mF/cm2 at the current density of 5 mA/cm2 in 1 M KOH electrolyte and good cycling stability of 90% capacitance retention after 5000 cycles at 20 mA/cm2.

A transition metal phosphide is an excellent candidate for supercapacitors due to its superior electrical conductivity and high theoretical capacity. In addition, compared with traditional 3D nano-materials, 2D nanosheets possess a greater specific surface area and shorter electron transport distance. In this study, a reasonable approach is proposed for the synthesis of ZIF-67 nanosheets on nickel foam with subsequent phosphorization by chemical vapor deposition (CVD) to obtain flake-like CoP combined with Ni2P (NCP/NF), in which nickel foam serves as the current collector as well as the resource of Ni to form Ni2P. Benefiting from the nanosheet array of CoP, the NCP/NF can improve the capacity of Ni2P from 0.57 C cm−2 to 1.43 C cm−2 at 1 mA cm−2. Furthermore, the NPC/NF/reduced graphene oxide (RGO) asymmetric supercapacitor (ASC) shows an energy density of 26.9 μW h cm−2 at a power density of 0.896 mW cm−2, and excellent cycling performance with a capacity retention of 93.75% after 5000 cycles at 10 mA cm−2.

Herein, paint residue (PR), a kind of industrial waste, is firstly used as a raw material for the synthesis of the activated carbon (AC) for supercapacitors via a simple and traditional two-step strategy before rinsing. The hydrofluoric acid greatly affects the structure of the AC, thereby affecting the performance of the supercapacitor. As evaluated in a three-electrode 6.0 M KOH system, the material exhibits a high gravimetric capacitance of 254 F g−1 at a current density of 1.0 A g−1, and excellent cycling stability with 100% retention after 10000 cycles. A voltage window of 0–1.4 V due to its high oxygen and heteroatom contents in a symmetrical supercapacitor from PR, which demonstrates a comparatively higher energy density of 15.22 Wh kg−1 at a power density of 1081 W kg−1, with good rate capability of 70% retention at 10 A g−1. The favorable capacitive performances make this environmentally unfriendly residue PR act as a new resource of carbonaceous materials for high-performance supercapacitors.

Chromatin is a unique structure of DNA and histone proteins in the cell nucleus and the site of dynamic regulation of gene expression. Soluble factors are known to affect the chromatin structure and function via activating or inhibiting specific transcription factors. Forces on chromatin come from exogenous stresses on the cell surface and/or endogenous stresses, which are regulated by substrate mechanics, geometry, and topology. Forces on chromatin involve direct (via adhesion molecules, cytoskeleton, and the linker of nucleoskeleton and cytoskeleton complexes) and indirect (via diffusion and/or translocation processes) signaling pathways to modulate levels of chromatin folding and deformation to regulate transcription, which is controlled by histone modifications and depends on magnitude, direction, rate/frequency, duration, and modes of stresses. The rapid force transmission pathway activates multiple genes simultaneously, and the force may act like a "supertranscription factor." The indirect mechanotransduction pathways and the rapid force transmission pathway together exert sustained impacts on the chromatin, the nucleus, and cell functions.

Design and fabrication of novel electrode materials with excellent specific capacitance and cycle stability are urgent for advanced energy storage devices, and the combinability of multiple modification methods is still insufficient. Herein, Ni

The large volume expansion and poor electrical conductivity of copper phosphide (Cu

In this paper, thermal stability of Sn-0.7Cu-10B-xNi/Co (SCB-xNi/Co, x = 0.05, 0.10 and 0.15, in wt.%) interface during multiple reflows was investigated. Both (Ni,Co)Sn3 and (Cu,Ni)6Sn5 phases were formed at the SCB-xNi/Co interface after the initial reflow. With the increase of reflow number, the thermal stability of intermetallic compounds (IMCs) layer at high temperature was significantly different. The content of Ni atoms determined the thermal stability of IMCs layer in the interface reaction process. At the IMCs layer at the SCB-0.15Ni/Co interface, Ni atoms were enriched excessively, but they were present in a dispersive distribution at SCB-0.05Ni/Co and SCB-0.10Ni/Co interfaces. Ni atoms occupied sublattice sites of Co atoms in CoSn3 phase, which could improve the high-temperature stability of IMCs layer, so the IMCs layer had the strongest thermal stability at the SCB-0.15Ni/Co interface.

Transition metal oxide materials prepared by dealloying method have attracted more and more attention and researches due to their high theoretical specific capacitance. In this study, nanoporous NiO@CoO composite electrodes were facilely synthesized by the melting and in situ corrosion, which exhibits an excellent electrochemical performance. The superior performance is ascribed to the reasonable pore size distribution (average pore diameter of 5.1 nm) and high specific surface area (50.75 m2 g−1) of the NiO@CoO, which provides a fast channel for electrolyte ions, shorten the free path of ion transfer and provide sufficient active sites for redox reactions. Moreover, the as-prepared material demonstrates a highest specific capacitance of 18.4 F cm−2 at a current density of 10 mA cm−2, and exhibits an excellent cycling stability with 93.9% retention after 5000 cycles at 30 mA cm−2. In a word, owing to the porous structure and pseudocapacitance effect, the NiO@CoO composite electrode has an ultra-high performance, which proves that this study has a great research value in the field of supercapacitors.

In this article, a novel supercapacitor electrode of pistil-like MnCo2O4.5@PANI nanorods supported by nickel foam with enhanced specific capacitance and cycle performance is fabricated thro...

Transition metal phosphides have been regarded as reliable supercapacitor electrode materials and extensively researched. In this work, a facile three-step way has been taken to synthesize NiCoP@NiCoP core–shell nanoarrays directly grown on carbon cloth, which was used as a high-performance supercapacitor electrode. Compared with the NiCo-LDH precursor and NiCoP nanowire and NiCoP nanosheet, NiCoP@NiCoP core–shell composite shows higher electrochemical performance owing to the integration of the advantages of phosphides and core–shell structure. To be specific, the as-fabricated NiCoP C–S electrode exhibits great electrochemical performance with high specific capacitance (1492.5 F g−1 at 1 A g−1), good rate performance (68.82% of the initial specific capacitance at 15 A g−1) and outstanding cycling stability (maintains 80.9% of the initial capacitances after 5000 cycles at 10 A g−1). Moreover, the assembled NiCoP C–S//rGO asymmetric supercapacitor device delivers a high energy density of 48.13 Wh kg−1 at the power density of 1125 W kg−1 and it still retains 20.94 Wh kg−1 at a high power density of 11250 W kg−1, indicating its great possibility of practical application.

A facile one-step hydrothermal route has been developed to directly synthesize CoNi2S4 nanoparticles on carbon fiber cloth (CC) to study the synergistic effect of bimetallic sulfides and carbon substrate on the electrochemical performance of supercapacitor electrode. The integrated binder-free CoNi2S4/CC electrode possesses an outstanding specific capacitance of 1165 F g−1 at 1 A g−1, and excellent rate capacitance (75.3% retention at 10 A g−1) in a three-electrode system, which is 27.2% and 32.2% higher than that of pure CoNi2S4 electrode. Detailed electrochemical tests and results showed that the surface capacitance effect ratio of the CoNi2S4/CC electrode is higher than that of pure CoNi2S4 electrode because of the introduction of CC. The CC substrates can provide a channel for electrolyte electrons and ions to promote reaction kinetics and shorten the diffusion distance of the redox reaction, thereby improving the performance of the pseudocapacitor CoNi2S4. Besides, the assembled asymmetric supercapacitors based on CoNi2S4/CC electrode and reduced graphene oxide electrode displayed a high specific energy density of 33.2 Wh kg−1 at 800 W kg−1, remarkable electrochemical stability (87.1% retention after 10,000 circulations) and high rate stability.

The interface reaction between the Sn-0.7Cu-10Bi-0.15Co and Co substrate during multiple reflow cycles and the growth and evolution rhythm of intermetallic compounds (IMCs) were investigated. The results showed that as the reflow cycles increased in number, different growth morphologies and evolution rules of the IMCs layer including its primary growth, dissolution and secondary growth appeared. In the primary stage of multiple reflows, Co could be continuously diffused from the Co substrate to the IMCs/solder interface to provide enough Co for the growth of IMCs layer. As the IMCs layer became thick, the diffusion of Co to the interface was inhibited, and the dynamic equilibrium of IMCs growth was broken. When the growth rate was higher than the dissolution rate, the IMCs layer grew as a whole and whereas the IMCs were dissolved. And under the action of adsorption force, the dissolved IMCs particles re-aggregated and grew.

Metal-organic frameworks (MOFs) have been used as a novel electrode material in terms of energy storage and conversion, owning to their stable porous architectures and exceptionally specific surface area. In this study, we have synthesized Ni-MOF and bimetallic Zn/Ni-MOF via a facile one-step hydrothermal method. Comparing with the pure Ni-MOF, the as-prepared Zn/Ni-MOF exhibits a superior energy storage capacity (878 F g−1 at 1 A g−1), better rate performance (536 F g−1 at 10 A g−1) and cycling stability (72% retention over 2500 charge/discharge cycles). In addition, the assembled asymmetric supercapacitor based on the Zn/Ni-MOF-1/NF//RGO shows a remarkable supercapacitive performance with the energy density of 30.51 Wh kg−1 at the power density of 800 W kg−1, and a superior cycling stability of 80.3% retention over 5000 cycles.

Transition metal phosphides (TMPs) are regarded as reliable supercapacitor electrode materials due to its high conductivity and excellent chemical activity. In this work, NiCo-LDH was synthesized via electrode position techniques, followed by one-step phosphating to convert the hydroxide into a phosphide. The obtained NiCoP shows 3D porous nanosheet stack structure, which provides a larger specific surface area and more active sites. The as-fabricated electrode exhibits good electrochemical performance with high specific capacitance (1142.84 F g−1 at 1 A g−1), good rate capabilities (62.07% of the initial specific capacitance at 10 A g−1), and outstanding cycle stability (maintains 74.5% of initial capacitances after 5000 cycles at 10 A g−1). Owning to superior electrical conductivity and excellent redox activity of phosphide, its voltage window and cycle stability are significantly improved compared with NiCo-LDH. In addition, NiCoP was used as the positive electrode and rGO as the negative electrode to fabricate the NiCoP//rGO asymmetric supercapacitor, which delivers a voltage window of 1.5 V and a high energy density of 14.7 Wh kg−1 at a power density of 753.6 W kg−1.

In this work, a novel hierarchical CuCo2O4@MnO2 composite with core-shell structure grown on RGO (coated on the surface of nickel foam (NF)) was synthesized via a facile hydrothermal route, in which MnO2 nanosheets uniformly wrapped around the surface of CuCo2O4 nanorods. RGO/CuCo2O4 composite was also prepared for comparison. Benefiting from their synergistic effect, RGO/CuCo2O4@MnO2 electrode delivered high specific capacitance of 850 F g−1 at 1 A g−1 in 2.0 M KOH electrolyte and an outstanding cycling stability with 94.2% retention over 3000 cycles, suggesting the great potential application of this material in advanced energy storage device.

Flexible electrodes for preparing core–shell structures are receiving increasing attention. A composite electrode material with NiCo2S4 as the core and Ni3S2 as the shell was successfully synthesized by hydrothermal synthesis and electrodeposition method. The prepared flexible NiCo2S4@Ni3S2 core/shell nanorod array has higher electrochemical performance, with specific capacitance of 5.714 F cm−2 at 2 mA cm−2 and excellent cycle stability. In addition, the prepared flexible hybrid supercapacitor has been assembled with NiCo2S4@Ni3S2 as the positive electrode and Fe2O3-rGO as the negative electrode, delivering an energy density of 5.9 mWh cm−3 at 171 mW cm−3. These results make the NiCo2S4@Ni3S2 a high-performance supercapacitor application candidate.

Adopting of hydroxides alone as electrode materials exhibit moderate performance due to its poor cycle stability and conductivity. In this study, an ultrathin nanostructure composed of nickel–cobalt layered double hydroxide (Ni–Co LDH) grown on carbon fiber cloth (CFC) has been prepared via a simple and efficient electrodeposition (ED) method without any binder or conductive agent, demonstrating an excellent cycle performance of Ni–Co LDH. The electrode delivers an extraordinary specific capacitance of 1540 F g−1 at a current density of 1 A g−1, with excellent rate capability of 1284.5 F g−1 even at 15 A g−1 as well as a great cycling stability of specific capacitance remaining 82.9% after 5000 cycles at 10 A g−1. Then, an asymmetric supercapacitor (ASC) device, with Ni–Co LDH as the positive electrode and rGO as the negative one, shows a perfect electrochemical performance. It is believed that in the future, this kind of electrode material will have a widespread application within the realm of electrochemical energy storage.

In this work, manganese was combined with ZIF-67 to form a multi-shell structure, and then the core-shell structure of Co3O4/MnCo2O4.5 as an electrode material was obtained by optimizing the thermal treatment, which perfectly inherited the rhombic dodecahedral shape of the ZIF-67 templates. Benefiting from the composition of core-shell structure and the synergistic effect of bimetallic manganese-cobalt oxides on shell surface, the Co3O4/MnCo2O4.5 reached a specific capacity of 636 F g−1 at a current density of 1 A g−1. Owing to a cycle life of 86% after 5000 charge and discharge cycles, its electrochemical performance had been improved significantly, compared with the Co3O4 acquired by pure ZIF-67 at a specific capacity of 320 F g−1 and a cycle life 79.9%. All of this confirmed the Co3O4/MnCo2O4.5 was an excellent electrode material for the pseudopotential capacitor.

In this study, bimetallic selenide NiCoSe2 has been successfully synthesized by using metal-organic framework (MOF) precursors. First, Ni-Co-ZIF (nickel and cobalt in the ZIF-67) with the same shape of ZIF-67 was synthesized as a precursor. Next, the NiCoSe2 with polyhedral morphology was produced by annealing the precursor with selenium (Se) powder at high temperature. The NiCoSe2 with a high surface area of 232.8 m2 g−1 exhibited a high specific capacitance of 300.2 F g−1 at 1 A g−1 in 2.0 M KOH electrolyte, and possessed an excellent cycling stability with almost no decrease in capacitance after 2000 cycles at 5 A g−1. These data suggested that this bimetallic selenide NiCoSe2 with polyhedral morphology could be a promising electrode material for supercapacitors.

Nitrogen-doped activated carbon (NAC) with a high specific surface area was successfully fabricated through graphitization derived from cotton and ammonia doping. The obtained NAC exhibits an enhanced specific capacitance of 156.4 F g−1 at 0.5 A g−1 and good cycling stability with capacitance retention of 95% after 5000 cycles. Hydrothermal route was used to synthesize CuCo2O4 nanoneedles with diameter of 20 to 50 nm. CuCo2O4 electrode showed good electrochemical performance with specific capacitance of 390 F g−1 at 0.5 A g−1 and high stability. Based on the two electrodes, an all-solid-state asymmetric supercapacitor (ASC) was assembled, which can achieve specific capacitance of 26.2 F g−1 at 1 A g−1, energy density of 8.2 Wh kg−1 at a power density of 750 W kg−1 and still retains 5.6 Wh kg−1 at power density of 7500 W kg−1. Two ASCs in series successfully illuminated 52 LEDs connected in parallel, indicating the practical application of the device.

Herein, we design and construct the hierarchical NiCo2O4@Ni0.85Se core-shell architecture directly growing on Ni foam as advanced materials for supercapacitor. The composite materials deliver excellent electrochemical performance with a high specific capacitance of 1454 F/g and superior cycle life with 88.5% retention after 10000 cycles, which ascribed to the synergistic effect of pure NiCo2O4 and Ni0.85Se. Furthermore, the NiCo2O4@Ni0.85Se//AC asymmetric supercapacitor were fabricated with a highest energy density of 29.3 W h kg−1 at power density of 799 W kg−1. It is expected that the NiCo2O4@Ni0.85Se will be a kind of promising electrode materials for supercapacitor.

In this paper, activated porous carbon (AC) derived from bagasse was prepared by carbonization and activation using KOH. Then, a hydrothermal route was employed to fabricate ultrathin manganese oxide (MnO2) nanosheets/activated porous carbon (AC) composite (MnO2/AC). AC and MnO2/AC composite were employed as negative and positive electrode materials for a supercapacitor, respectively. An AC electrode delivers excellent electrochemical properties with a specific capacitance of 89 F g−1 at 1 A g−1 and super cycling stability of 89% capacitance retention after 5000 cycles. For a MnO2/AC composite, its specific capacitance can reach 492.5 F g−1 at 1 A g−1, but its cycle performance (78.4% capacitance retention after 5000 cycles) is lower than that of AC (89%). In view of the good electrochemical performance of AC and MnO2/AC composite, a MnO2/AC//AC all-solid-state asymmetric supercapacitor (ASC) was assembled. The constructed ASC exhibits high specific capacitance of 69.375 F g−1 at 1 A g−1 and delivers a high energy density of 24.67 Wh kg−1 at a power density of 814.8 W kg−1. Two ASCs in series can power one LED for more than 70 s. This work demonstrates that MnO2/AC//AC asymmetric supercapacitor shows good practical value.

Tumorigenic cells, when facing a hostile environment, may enter a dormant state, leading to long-term tumor survival, relapse, and metastasis. To date, the molecular mechanism of tumor cell dormancy remains poorly understood. Methods: A soft, 3-dimentional (3D) fibrin gel culture system was used to mechanically select and grow highly malignant and tumorigenic melanoma tumor-repopulating cells (TRCs). We cultured control melanoma TRCs, TRCs with Sox2 knockdown, TRCs with Sox2 knockout, and a 2D control for in vitro and in vivo experiments. Western blotting, immunofluorescence, and flow cytometry analysis were performed to examine TRC dormancy and exit from dormancy. Results: Under a low-expression condition, we show that Sox2, a stemness molecule participates in dormancy regulation of highly tumorigenic cells that can repopulate a tumor (TRCs). Intriguingly, complete depletion of Sox2 via knockout results in dormancy exit and growth resumption of melanoma TRCs in culture and elevation of melanoma TRC apoptosis. Mice that are injected subcutaneously with Sox2-depleted melanoma TRCs do not form tumors and survive much longer than those injected with melanoma TRCs. We found that complete depletion of Sox2 promotes nuclear translocation of phosphorylated STAT3, where it binds to the p53 gene promoter, thus activating the p53-caspase3 cascade. Conclusion: These findings provide a novel insight into the role of the Sox2 gene in tumor cell stemness, tumor dormancy, and apoptosis.