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Polyimide-based nitrogen-doped ordered mesoporous carbon was successfully synthesised utilising SBA-15 as a hard template. By controlling the molar ratio of 4,4′-oxydianiline to pyromellitic dianhydride during copolymerising and carbonisation, nitrogen-doped ordered mesoporous carbon (NOMCx) with various nitrogen content and pore distribution were obtained. When the molar ratio of 4,4′-oxydianiline to pyromellitic dianhydride was 6, NOMC6 presented the highest content of nitrogen (7.94 wt%) and moderate specific surface area (890 m2 g−1). Accordingly, NOMC6 showed a high specific capacitance of 282 F g−1 at 0.1 A g−1, and excellent cycle stability (no capacitance loss over 10,000 cycles) in 1 M H2SO4. The synthesised ordered mesoporous carbons do not show a significant decrease of capacitive performance in the current density range of 2 to 20 A g−1. Furthermore, a symmetrical supercapacitor consisting of two NOMC6 electrodes exhibited an energy density of 4.77 Wh kg−1 at power density of 500 W kg−1 (1 A g−1).

To meet the demand for high-power-density and long lifespan surpercapacitors (SCs), the Ni–P@Ni HL/CC-1h with a core–shell structure (Ni–P sphere as the core and nanoflake with the Ni and Ni–P heterogeneous layer as shell) was constructed via a facile strategy. The strategy included hydrothermal synthesis of Ni–P spheres with large Ni surface layer on carbon cloth (Ni–P@Ni HL/CC) and subsequent chemical dealloying using HCl as etching solution in order to remove the redundant Ni substances. The morphology, composition, and electrochemical performances of raw Ni–P@Ni HL/CC and the corresponding samples obtained by different dealloying times (0.5, 1, and 2 h) were characterized. Interestingly, the Ni–P@Ni HL/CC-1h presents a unique structure with a nanoflake shell and a porous core, which can provide a large number of exposed active sites, accelerate electrolyte ion diffusion and support ultra-long cycling. Furthermore, the Ni species existing in the outer flake can increase the conductivity and promote the capacitance during the charge–discharge processes. The Ni–P@Ni HL/CC-1h exhibited high specific capacity of 280.8 C g−1 at current density of 1 mA cm−2, high rate retention of 76.2% at 20 mA cm−2. The maximum specific capacity could reach 388.8 C g−1 at 8 mA cm−2, and maintained the 92.6% retention after 3000 cycles. Moreover, the Ni–P@Ni HL/CC-1h//AC all-solid-state asymmetric supercapacitor (ASC) exhibited high specific capacity, 86.0% retention after 10,000 cycles and high energy density of 27.6 Wh kg−1 at power density of 942.8 W kg−1.

Metal-organic frameworks featuring controllable morphologies and tunable compositions and pore structures are widely used as precursors for supercapacitors electrode materials. A zinc/cobalt-based zeolitic imidazolate framework was utilized as a precursor to synthesize N, S-codoped porous carbon supported CoS2 nanocomposites, using a two-step (carbonization and sulfurization) procedure. The as-prepared materials maintained the rhombic dodecahedral structure of the precursors, and carbon nanotubes were rooted onto the nanocomposite surface. The N, S-codoped porous carbon supported CoS2 nanocomposite hybrid electrode exhibited excellent electrochemical performance: high specific capacitance (635.8 F/g at 1 A/g), good rate capability (544.2 F/g at 10 A/g), and long-term cycling stability (88.0% retained after 2000 cycles). Moreover, the energy density of the N, S-codoped porous carbon-supported CoS2 nanocomposites//activated carbon asymmetric supercapacitor reached 14.1 Wh/kg at the power density of 0.71 kW/kg, and its capacitance remained 92.2% after 2000 cycles in the 0–1.4 V potential range.

A polyaniline/molybdenum trioxide/activated carbon cloth (PANI/MoO3/ACC) composite was successfully synthesized via facile hydrothermal and in-situ polymerization reactions. The morphology and microstructure of the PANI/MoO3/ACC composite were investigated by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The electrochemical performance of the as-prepared electrode was evaluated by cyclic voltammetry, galvanostatic charge-discharge measurements, and electrochemical impedance spectroscopy. The coating PANI layer in PANI/MoO3/ACC increases the electrochemical activity of MoO3 and accelerates the ion diffusion and electron transfer. Due to synergistic effects between the components, PANI/MoO3/ACC exhibits a specific capacitance of 1050 F g−1, significantly higher than that of MoO3/ACC (296.7 F g−1) and PANI/CC (500.0 F g−1) at a current density of 0.5 A g−1 in 1 M H2SO4 aqueous electrolyte, as well as good cycling stability for 2000 cycles with 71% retention. It also displays lower ion diffusion and charge transfer resistance, as evidenced by the electrochemical impedance data. PANI/MoO3/ACC exhibits excellent electrochemical performance and is thus a promising electrode material for supercapacitors.