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Nickel ferrite owns a lot of advantages as electrode materials for supercapacitor, such as high energy density and excellent theoretical capacity. Whereas, the electrochemical performances of NiFe 2 O 4 in terms of rate performance and cycle stability are not satisfactory due to the low conductivity. While carbon fiber is a kind of material with high conductivity. Hence, NiFe 2 O 4 @ slit modified hollow carbon fiber is obtained through the coaxial electrospinning method. The slits on hollow carbon fibers are beneficial to the contact of inner NiFe 2 O 4 nanoparticles with electrolyte. Results of electrochemical tests show that at a current density of 1 A/g, the specific capacitance of NiFe 2 O 4 @ slit modified hollow carbon fiber is calculated to be 225.4 F/g, higher than that of NiFe 2 O 4 nanoparticles of 134.8 F/g. Moreover, a better cycle and rate performances (100 % vs 80 %; 71.9 % vs 47.5 %) are achieved. This work displays that slit modified hollow carbon fiber can improve the electrochemical performance of NiFe 2 O 4 efficiently. [Display omitted] • Carbon fibers are introduced to enhance the rate and cycle performances of NiFe 2 O 4. • Slits are obtained utilizing Al 2 O 3 sacrificial hard templates. • Slits are beneficial to the contact of NiFe 2 O 4 and electrolyte. [ABSTRACT FROM AUTHOR]

As the precursor of MXenes (2D transition metal carbides, carbon nitrides and nitrides), MAX phase materials have attracted ever-increasing attention in electrochemical applications. In this work, we have successfully hybridized a MAX phase, Ti 2 SnC, with various ratios of carbon nanofibers (CNFs) via electrospinning. The results show that the Ti 2 SnC/CNFs compounds possess a stable lithium ion storage ability as an anode material, reaching a stable specific capacity of up to 367.5 mAh·g−1 after 500 charge/discharge cycles at the current density of 1.0 A g−1, which are drastically better than some other MAX phase materials such as Ti 3 SiC 2 and Nb 2 SnC. This strategy provides a new pathway for the improvement of the electrochemical stability of MAX phase, which has a wide application prospect. • Ti 2 SnC/CNFs was successfully prepared by an electrospinning method. • CNFs retard the volume expansion of Ti 2 SnC during the charge/discharge process. • Ti 2 SnC/CNFs performed stable lithium ion capacitance (367.5 mAh·g−1 at 1.0 A g−1). [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]