Ni embedded carbon nanofibers/ Ni-Al LDHs with multicomponent synergy for hybrid supercapacitor electrodes

Preparation of multi-component composites is an effective strategy to obtain novel and highly efficient electrode materials. Herein, to achieve the synergistic effect of compositions and microstructures, hybrid materials made of Ni embedded carbon nanofibers/Ni-Al layered double hydroxides (Ni-Al LDH) were prepared in this work. Ni embedded carbon nanofibers were first fabricated ingeniously via the combination of electrospinning and thermal treatment, which provided a great number of active sites and increased the space for ion transportation. Subsequently, we combined Ni embedded carbon nanofibers with a nanostructured Ni-Al LDH via a hydrothermal process. It was reasoned that Ni embedded carbon nanofibers could help optimize microstructures of Ni-Al LDH, which could alleviate the aggregation problem and improve the rate performance of Ni-Al LDH. A series of composites were made and evaluated. It was found out that, the 3 % Ni embedded carbon nanofibers/ Ni-Al-LDH (3 %-Ni-CNA) electrode achieved an outstanding specific capacity of 1228.2 C g−1 at 1 A g−1, an excellent rate performance of 68.1 % of initial capacity even at 20 A g−1,and a long-cycle lifetime with 88.6 % of initial capacity retention after 10,000 cycles at 8 A g−1. In addition, an asymmetric supercapacitor device based on 3 %-Ni-CNA and AC was constructed and demonstrated a high energy density of 74.9 W h kg−1 at 800 W kg−1 It is noteworthy that the capacity of the device achieved 91.4 % retention after 10,000 cycles at 6 A g−1. Hence, the 3 %-Ni-CNA could be an ideal material for the hybrid supercapacitors and other energy storage applications. At the same time, it provides a novel mentality for improving the electrical conductivity of electrodes and constructing nanomaterials with heterostructures