Direct growth of nickel terephthalate on Ni foam with large mass-loading for high-performance supercapacitors

It is always of great significance to explore novel electrode materials for supercapacitors, one of the next-generation energy storage devices. In this work, we have successfully fabricated a nickel terephthalate (Ni–Tp) complex on Ni foam with high mass-loading via a facile hydrothermal route, which can be directly used as an electrode for supercapacitors. More significantly, the electrochemical properties would be substantially improved by the electrochemical deposition of polyaniline (PANI) nanofibers on the surface. The resulting Ni–Tp/PANI electrode shows much higher specific capacitance, rate capability and cycling stability than the pristine Ni–Tp electrode. The electrochemical measurements demonstrate that the obtained Ni–Tp/PANI electrode possesses a specific capacitance of 10.327 F cm−2 (938.845 F g−1) at a current density of 20 mA cm−2 (1.818 A g−1) and cycling stability with a capacitance retention of 85.4% after 3000 cycles at a current density of 50 mA cm−2. An asymmetric supercapacitor is constructed by integrating the Ni–Tp/PANI sample as the positive electrode and activated carbon as the negative electrode. The fabricated device can reach a specific capacitance of 59.498 F g−1 at a current density of 0.556 A g−1 (10 mA cm−2) and an energy density of 19.853 W h kg−1 at a power density of 430.556 W kg−1 with a voltage window of 1.55 V. For the achieved high electrochemical performance, Ni–Tp can be expected to be a favorable candidate for supercapacitors.