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Core-shell hierarchical structured composites have demonstrated great advantages in numerous energy storage devices. In particular, structured composites with rationally structural components and controllable morphology are the most effective in enhancing electrochemical properties. In this work, MnO 2 @NiCo 2 O 4 @Ti 3 SiC 2 /CC (carbon cloth) core-shell hierarchical structured composites were designed and successfully synthesized via electrospinning followed by a two-step hydrothermal reaction. The Ti 3 SiC 2 /CC nanofibers and core-shell nanoarrays were able to improve the specific capacitance and cycling stability. In the three-electrode system, the specific capacitance of MnO 2 @NiCo 2 O 4 @Ti 3 SiC 2 /CC was observed as 1938.2 F/g at a current density of 1 A/g, while the rate capability retention was observed as 81.7% between 1 and 10 A/g. Furthermore, a superior cycling stability was observed following 5000 cycles with a specific capacitance retention rate of 55.4%. Employing MnO 2 @NiCo 2 O 4 @Ti 3 SiC 2 /CC as the all solid-state supercapacitor positive electrode exhibited a high energy density of 58.0 W h/kg at the power density of 800 W/kg. Results demonstrate the potential of the MnO 2 @NiCo 2 O 4 @Ti 3 SiC 2 /CC as an electrode material with phenomenal electrochemical properties for supercapacitors. [ABSTRACT FROM AUTHOR]

Bimetallic carbides have aroused wide attention for energy-storage applications recently. In this work, one-dimensional Fe 2 MoC/CNFs (Fe 2 MoC/C nanofibers) are successfully synthesized via a facile electrospinning method for the first time. To obtain the most integrated structure between the Fe 2 MoC nanoparticles and carbon nanofibers, we explore the optimal heating rate during the carbonization treatment. Fe 2 MoC/CNFs exhibits an integrated one-dimensional structure under 800 °C with a heating rate of 5 °C/min. As revealed in the experimental results, Fe 2 MoC/CNFs possesses a high specific surface area of 196.9 m2/g, a high specific capacitance of 347.8 F/g at the current density of 1 A/g, an excellent rate capability of 91% capacitance retention from 1 A/g to 40 A/g, and shows superior cycling stability with the capacitance retention of about 85.6% and Coulombic efficiency of about 100% after 5000 cycles. An asymmetric supercapacitor coin-cell device using Fe 2 MoC/CNFs as the positive electrode displays an energy density of 14.5 Wh/kg at a power density of 300 W/kg and an outstanding cycling life of 93% retention after 5000 cycles. The impressive electrochemical performance indicates that the Fe 2 MoC/CNFs composite is a promising material for efficient supercapacitors. Image 1 • Fe 2 MoC nanofibers can be prepared via a facile electrospinning method. • Fe 2 MoC/CNFs-5 exhibits a superior rate capability and cycle stability. • ASC coin-cell device shows a promising energy and power density. [ABSTRACT FROM AUTHOR]