Search

A three-model fluorescence “ON–OFF–ON” system, from a tris-bis(urea) anion ligand (LMe) to anionocage 1Me and then to the host–guest complex, in response to anion coordination and halogenated hydrocarbon encapsulation, was established.

A facile solid-state Matryoshka-doll-like microwave strategy is developed to synthesize the composites of NiSe2 and N–C in just 20 minutes. The microwave functionalized NiSe2/N–C SIB anode displays an excellent cycling stability (2000 cycles at 1.0 A g−1).

CoFe alloy nanoparticles (NPs) encapsulated in a three-dimensional (3D) honeycomb-like porous N-doped graphitic carbon (CoFe/N-GC) framework were fabricated by a facile polymer thermal treatment method.

With a high energy density, lithium-sulfur batteries (LSB) are regarded as one of the promising next-generation energy storage systems. However, many challenges hinder the practical applications of LSB, such as the dendrite formations/parasitic reactions on the Li metal anode and the "shuttle effect" of lithium polysulfides of the LSB cathode. Herein, a novel diluted medium-concentrated electrolyte (DMCE) is developed by adding 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether (TTE) into a dual salt medium-concentrated electrolyte (MCE) consisting of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI)-lithium bis(fluorosulfonyl)imide (LiFSI)/tetrahydrofuran (THF)-dipropyl ether (DPE). The optimized DMCE electrolyte is capable of protecting the Li metal anode and suppresses the dissolution of polysulfides and the "shuttle effect", delivering a high coulombic efficiency (CE) of Li plating-stripping up to 99.6% even at a low concentration of Li salt (1.0-2.0 m). Impressively, compared with the cells cycled in the MCE electrolyte, the LiS cells with the DMCE-2.0 m electrolyte have delivered an enhanced initial capacity of 682 mAh g

Extensive studies on trirutile Li0.5FeF3 phase have been commissioned in the context of the Li–Fe–F system for Li-ion batteries. However, progress in electrochemical and structural studies has been...

This work involves the preparation and characterization of poly(styrene-b-isoprene-b-styrene)-poly(dimethylsiloxane-co-methylhydrosiloxane) (SIS-c-PDMS-co-PMHS) crosslinked membranes towards CH4/N2 separation. SIS-c-PDMS-co-PMHS was synthesized via a simple hydrosilylation reaction with various PDMS-co-PMHS contents. The structure of crosslinked membranes was investigated by Fourier transform infrared spectroscopy, indicating the degree of hydrosilylation reaction. The morphology of sample membranes was observed in detail by means of Scanning Electron Microscope analysis. Thermodynamic stability and the crosslinked behavior of crosslinked membranes were explored by thermogravimetric analysis and Soxhlet extraction experiments. Furthermore, single gas (CH4, N2) permeability was measured using the time-lag method. The CH4 permeability of crosslinked membranes with 70 wt% PDMS-co-PMHS could reach 503 Barrer at 25 °C and 1 bar, which is significantly greater than that of SIS (25.9 Barrer), while the CH4/N2 ideal selectivity hardly changed. Notably, CH4 permeability further improved by 77.6% (893.4 Barrer) as the temperature increased to 55 °C. For the CH4/N2 (50/50 vol%) mixed gas, the SIS-c-PDMS-co-PMHS-70 sample membrane exhibited ideal gas separation performance relative to that of the pure SIS membrane (CH4: 447.4 vs. 24.2 Barrer，N2: 188.1 vs. 9.46 Barrer).

Herein, we present an ultrafast microwave approach for fabricating MoS2/MoO2@CNT nanocomposites toward supercapacitor electrodes with excellent cycle stability. The surface chemistry, crystalline structure and morphology of the as-produced nanocomposites were characterized by FTIR, XRD, XPS, EDS and SEM. It was found that MoS2/MoO2 nanoparticles could grow uniformly on the surface of CNTs, and the CNTs can provide a transport path for ions in electrolytes and reduce energy loss, thus leading to enhanced electrochemical performance of the resultant nanocomposites. Electrochemical results showed that the capacitance of the nanocomposite electrode was increased by 187.1% after 25 000 cycles at a current density of 5 A g−1, indicating outstanding cycling stability. Also, the maximum capacitance of the optimized MoS2/MoO2@CNT electrode can reach 228.4 F g−1 at 0.5 A g−1. Moreover, an asymmetric supercapacitor (MoS2/MoO2@CNT//AC) was assembled which exhibited a maximum energy density of 11.88 W h kg−1 and a power density of 2 kW kg−1, respectively. Intriguingly, the asymmetric supercapacitors could successfully light three LED lights for 5 minutes, showing their great practical application potential in portable supercapacitors.

In this work, a unique Ppy@NiCo 2 S 4 core-shell heterostructure material is prepared taking polypyrrole (Ppy) nanotubes as skeleton through a simple and environmentally friendly hydrothermal method. The heterostructured structure with Ppy nanotubes (NTs) as the core and intertwined flake-like NiCo 2 S 4 as the outer shell, holds a large specific surface area (217 m 2 g −1 ), convenient charge transport channel, high specific capacitance (908.1 F g −1 at a current density of 1 A g −1 ), and excellent cycling performance (87.7% of initial value is retained after 2000 cycles). What’s more, an asymmetric supercapacitor is fabricated by employing Ppy@NiCo 2 S 4 core-shell heterostructured material as positive and nitrogen-doped carbon nanotubes (N-C NTs) as negative electrode. This Ppy@NiCo 2 S 4 //N-C asymmetric supercapacitor effectively provides a high energy density over 50.82 Wh kg −1 with a high power density of 160 W kg −1 and preeminent cyclic stability of 126.6% after 2000 cycles. Due to the introduction of one-dimensional flexible Ppy inner core, as-designed the core-shell heterostructure composite may be promising in the flexible energy storage devices.

In this work, a unique N–C@NiMoO4 composite with a double-shelled hollow microtube structure has been developed through a simple and low-cost growth process. The composite contains a NiMoO4 outer shell with high electrochemical activity and hollow nitrogen-doped carbon nanotubes (N–C NTs) with high conductivity, resulting in a high performance electrode material. The existence of N–C NTs effectively prevents the accumulation and agglomeration of the NiMoO4 nanosheets during the formation of a uniform outer shell, providing a higher specific surface area (258.2 m2 g−1). The electrochemical study displays that the C@NiMoO4 composite has a specific capacitance as high as 1242 F g−1 at a current density of 1 A g−1, and about 82.9% cycling stability after 2000 cycles. Moreover, the as-fabricated C@NiMoO4//N–C asymmetric supercapacitor (ASC) can achieve a maximum high energy density of 44.6 W h kg−1 at a power density of 250.4 W kg−1. These results imply that the C@NiMoO4 composite with a double-shelled hollow tube-structure is a promising candidate for high performance supercapacitors.

In this study, hierarchical CuCo2O4@CuCo2O4 nanowire arrays have been directly fabricated on Ni foam via a two-step method that involves hydrothermal and calcination processes. The CuCo2O4 nanowires are fully covered by porous CuCo2O4 nanosheets. The as-prepared double-metal oxide hierarchical nanowire arrays exhibit superior redox reactivity for supercapacitors. The unique hierarchical nanowire arrays own a specific capacitance of up to 888.9 F g−1 at 2 mA cm−2, which is much higher than the specific capacitance values of simple CuCo2O4 nanowire arrays. The hierarchical CuCo2O4 nanostructure shows superior cycling stability, retaining 101.77% of the initial capacitance after 2000 cycles. Moreover, by employing CuCo2O4@CuCo2O4 as the positive electrode and active carbon (AC) as the negative electrode, an asymmetric supercapacitor (ASC) device was fabricated and it displayed an excellent electrochemical performance. The enhanced electrochemical performance is mainly due to its unique hierarchical structure, which provides good ion and electron transfer, a large number of active sites, and the synergistic effect. In view of their outstanding electrochemical performance and the cost-effective fabrication process, this unique integrated nanoarchitecture may offer great promise as superior electrodes for high-performance supercapacitors.

In this study, we have developed a facile in situ growth process to prepare three-dimensional (3D) interconnected CuS nanowalls on Ni foam, which have a large number of nanosheets on both sides of the nanowalls. The fabrication route contains the replacement process of Cu submicrometer-sized cubes on Ni foam and subsequent in situ growth process of interconnected rough CuS nanowalls (RCuS) on Ni foam via a hydrothermal method. The RCuS electrode displays excellent performance, demonstrating a specific capacitance of 1124 F g−1 at a current density of 15 mA cm−2 and 912.5 F g−1 at 30 mA cm−2 with a good cycling ability (∼90.7% of the initial specific capacitance remained after 2000 cycles), which is much higher than that of the CuS electrode through a simple hydrothermal (HCuS), taking copper dichloride as the copper source. The excellent electrochemical performance may be attributed to the high conductivity, large specific surface, and strong bonding between nanowalls and the Ni foam. The demonstrated high specific capacity and remarkable rate performance of the CuS nanowalls, together with the flexibility of the nickel foam substrate, make the 3D nanostructured electrode ideally suited for low-cost, high-performance supercapacitors.