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As a new generation of energy storage devices, lithium-ion capacitors (LICs) rationally combine high energy density and high power density, providing an alternative solution for multi-functional electronic equipment and state grid system. However, the dynamic mismatch between the battery-type anode and the capacitor-type cathode seriously limits its development and application. Herein, a high performance LIC simultaneously using carbon materials derived from Ethylenediaminetetraacetic Acid Ferric Sodium Salt (EDTA-Na-Fe) was prepared. By calcination of EDTA-Na-Fe in an inert atmosphere, nitrogen-doped carbon frameworks (NCF) can be obtained which possess a high reversible capacity and excellent rate-capability. Using this NCF as the anode and cathode of the LICs, the hybrid devices with a wide voltage window of 0.5-4.0 V are obtained. The employment of the same materials as the anode and cathode can largely simplify the fabrication process. The energy density of LICs can reach 193.4 Wh·kg-1 at a power density of 225 W·kg-1. This reasonable dynamic matching strategy can be helpful for the application of LICs.

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We successfully synthesized N -doped carbon frameworks embedded with ZnCo nanoparticles on the surface of Ag NWs (Ag@ZnCo/NCF nanohybrids) by pyrolyzing AgNW@ZIF-8@ZIF-67 precursors. The synergistic effect among the components of Ag@ZnCo/NCF contributed to the enhancement of electrocatalytic performance on overall water splitting. Metal-organic frameworks (MOFs)-derived catalysts exhibit highly-efficient hydrogen or oxygen evolution performance on water splitting. However, it is an urgent problem to construct bifunctional electrocatalysts for both hydrogen and oxygen evolution performance. Herein, we adopted Ag nanowires as templates to prepare one-dimensional Ag nanowire@ZIF-8@ZIF-67 precursors (1D AgNW@ZIF-8@ZIF-67). Through pyrolysis, AgNW@ZIF-8@ZIF-67 precursors transformed into nitrogen-doped carbon frameworks (NCF) embedded with zinc-cobalt (ZnCo) nanoparticles on the surface of Ag NWs (denoted as Ag@ZnCo/NCF nanohybrids). The nanohybrids were consisted of Ag NWs with good conductivity and ZnCo/NCF nanohybrids with rich accessible active sites. Benefiting from their large specific surface area, accessible active sites and synergistic effect among components, Ag@ZnCo/NCF nanohybrids exhibit lower overpotentials of 139 mV and 279 mV at the current density of 10 mA cm−2 for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in alkaline solution, severally. Compared with other catalysts, Ag@ZnCo/NCF nanohybrids possess smaller Tafel slope, indicating their higher catalytic activity. This work provides a new perspective for designing low-cost and highly efficient bifunctional electrocatalysts for overall water splitting. [ABSTRACT FROM AUTHOR]

[Display omitted] • The ultrafine Co nanoparticles (12–15 nm) improve rate performance. • The introduction of N-doping and Co particles improves ion/electron conduction. • The coexistence of the micro-mesopores helps to accelerate kinetics. • The LIC has high energy density (125.28 Wh kg−1) and power density (10 kW kg−1). In this work, we propose to prepare a nitrogen-doped nanocomposite (Co@N-C) by one-step carbonization of the zeolite imidazole ester framework structure material (ZIF-67). Among them, the composite material uses porous carbon dodecahedron as the supporting framework, and the metal Co nanoparticles (12–15 nm) are encapsulated inside the carbon framework. The prepared nanocomposite demonstrates excellent electrochemical performance, and the electrode kinetic analysis shows extremely high pseudo-capacitance contribution and good cycle stability, almost no fluctuations during the cycle. Moreover, our assembled hybrid lithium-ion capacitor (LIC) has superb energy–density (125.28 Wh kg−1) and power-density (10 kW kg−1), and excellent cycle life (91.74% was retained after 1000 cycles), which is ascribed to the combined effect between the ideal component and multilayer structure of the prepared nanohybrid. This research work provides an effective solution for energy storage systems that take into account both high power and high energy density. [ABSTRACT FROM AUTHOR]

• Ru doped ZIF-8-based nitrogen carbon precursor was synthesized by one-pot method. • The low load of noble-metal Ru (0.39 wt%) and carbon nanotubes on the surface. • A cheaper and facile synthetic approach to fabricate low-noble metal catalyst is proposed. Hydrogen is one of the most desirable alternatives to fossil fuel due to its cleanliness, renewability and large energy density. Efficient and durable electrocatalyst toward hydrogen evolution reaction (HER) is an urgent need for the sustainable development and long-term environmental conservation. The noble metal(Pt/Ru/Ir) has a favorable performance for HER but the high price and the low reserve hinder its further application. Meanwhile, the non-noble metal electrocatalysts can hardly achieve a satisfactory stability and efficiency. Therefore, this paper reports a Ru embedded N-doped carbon framework material as low-noble metal catalyst which has low loading of Ru (0.39 wt%) and exhibits the desirable overpotential of 181 mV at 10 mA cm−2 in alkaline and 298 mV at 10 mA cm−2 in acidic solution. Besides, it retains 94. 1% current density after durability potentiostatic tests for 30,000 s while the commercial 20 wt% Pt/C can only retain 84. 2%, which suggests a superior stability. [ABSTRACT FROM AUTHOR]

Layered transition metal sulfides have drawn great research attention due to their excellent properties for energy storage and conversion devices. However, there is a need to innovate effective approaches to enhance the performance of metal sulfides for modern energy storage devices. Herein, a rational surface engineering strategy was adapted to design tungsten disulfide nanosheets coated polyetherimide (WS 2 @PEI) nanocomposite by facile sol-gel method combined with a subsequent pyrolysis. The WS 2 @NC nanocomposite exhibits excellent lithium-ion storage properties as compared to pristine WS 2 nanosheets. The origin of enhanced performance of WS 2 @NC nanocomposite is carbon-sulphur (C–S) bonding with WS 2 , offered by thermally stable polyetherimide (N–C). The increased strength of charging is subjected to C–S and N–C bindings, which significantly enhanced the active sites and defects in WS 2 @NC nanocomposite framework. The thin porous carbon layer provided elasticity to control the volume expansion during the lithium ions (Li+) insertion/deinsertion, while nitrogen and sulphur components offered more active sites and defects in the nanocomposite for reversible adsorption of Li+ ions. Thus, the WS 2 @NC nanocomposite could deliver high reversible specific capacity of 712 mAh g−1 at 0.1 A g−1 after 100 cycles and 417.6 mAh g−1 even at high current density of 0.8 A g−1 with 99% average coulombic efficiency. Image 1 • WS 2 @NC was designed via sol gel method followed by pyrolysis yield WS 2 @NC. • The tailored capacity of WS 2 @NC depends on the C–S and N–C bonding. • The porous carbon layer provided elasticity for volume expansion and reversible Li+ ions adsorption. • The WS 2 @NC exhibited reversible capacity of 712 mAh g−1 at 0.1 A g−1 with coulombic efficiency of ≥95%. [ABSTRACT FROM AUTHOR]