One-step synthesis of Ni/Ni(OH)₂@Multiwalled carbon nanotube coaxial nanocable film for high performance supercapacitors

Ni/Ni(OH)₂@multiwalled carbon nanotube (MWCNT) coaxial nanocable (NMCNC) film was fabricated by an easy and low cost one-step electrophoretic deposition approach. The formation mechanism was discussed in details. For comparison, MWCNT film and Ni/Ni(OH)₂ film were also fabricated. Compared with its counterpart Ni/Ni(OH)₂ film, the NMCNC film exhibited more homogeneous and nanoporous morphology, much larger surface area and thus better capacitive performance. The NMCNC film showed a high specific capacitance of 1642 F g^-1 at a high current density of 5 A g ^-1. As the current was increased to 100 A g^-1, the NMCNC film could retain a relatively high capacitance of 895 F g^-1. After 1000 charge/discharge cycles at 5 A g^-1, the NMCNC film showed a capacitance retention rate of 81%. The excellent capacitive performance can be attributed to the structure advantages of the NMCNC film.