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Hybrid materials PPy/Ni–Co LDH based on polypyrrole nanotubes and Ni–Co LDH from ZIF-67 templates were employed as electrode materials for supercapacitors, where Ni–Co LDH possesses a hollow structure. With the help of appreciative composition and a hollow structure, the optimum PPy/Ni–Co LDH shows an excellent performance with high specific capacitances (4.4 C cm−2 at 1 mA cm−2 and 3.35 C cm−2 at 20 mA cm−2). [ABSTRACT FROM AUTHOR]

Reasonable construction of electrodes materials with heterostructures is a very effective way to enhance the electrochemical performance. Herein, a series of hybrid electrodes materials (PPy/Ni–Co LDH) based on nickel-cobalt layered double hydroxide (Ni–Co LDH) with zeolitic imidazolate framework-67 (ZIF-67) as the template and polypyrrole (PPy) nanotubes have been synthesized. Various precursors PPy/ZIF-67 based on polypyrrole nanotubes with the same amount have been prepared, where the mass ratio of polypyrrole nanotubes to ZIF-67 are varied in the process of crystallization. As-synthesized precursors PPy/ZIF-67 serve as sacrificial templates and give birth to various hybrid electrodes materials PPy/Ni–Co LDH with the core-shell structure, where Ni–Co LDH is closely coated on the external surface of polypyrrole nanotubes. The experimental findings reveal the electrochemical performance of PPy/Ni–Co LDH becomes better and better with increasing masses of Ni–Co LDH. Benefiting from their core-shell structure and the synergy effect between polypyrrole nanotubes and Ni–Co LDH, the optimized sample displays a specific capacitance of 13.0 F cm−2 (1858.3 F g−1) at 1 mA cm−2 and a favorable rate capability. Furthermore, a symmetric coin-type hybrid supercapacitor based on the optimized sample has also been fabricated, and exhibits an energy density of 10.425 mWh·cm−2 at the power density of 0.25 mW cm−2. Hybrids PPy/Ni-Co LDH are used for supercapacitors and show high specific capacitances via synergistic effect between Ni-Co LDH and PPy. Image 1 • Polypyrrole inter-connected hollow Ni/Co LDH hybrids are prepared. • Their performance are better and better with increasing Ni–Co LDH masses. • The optimum sample displays a capacity of 13 F/cm2 and a favorable rate capability. • Their performance can attribute to the synergy effect between PPy and Ni–Co LDH. [ABSTRACT FROM AUTHOR]