•Hollow CuO/Co3O4 hybrids are synthesized from bimetallic-Schiff base polymer precursors.•The capacitance of the CuO/Co3O4 hybrids keeps a growth tendency after 2000 cycles.•A synergetic effect is found for the hybrids in electrochemical energy storage process.Hollow CuO/Co3O4 hybrids, which inherited from its coordination polymer precursor consisting of sheets layer and nanoparticles layer composites, were synthesized and characterized by SEM, EDX, XRD and XPS. To assess its electrochemical capacitive performances, cyclic voltammetry, galvanostatic charging-discharging measurements and A.C. impedance tests were performed successively. The CuO/Co3O4 hybrids had higher capacitance and lower charge transfer resistance than bare Co3O4 nanostructures, revealing that it provided a protection layer and produced a synergistic effect due to the existence of CuO layer. The distinct synergistic effect could be further confirmed by endurance cycling tests. The capacitance of the CuO/Co3O4 hybrids was 111% retained after 500 cycles at a charging rate of 1.0 A g−1 and remained an intense growth trend after 2000 cycles at scan rate of 200 mV s−1.Hollow CuO/Co3O4 hybrids are synthesized and display a peculiar synergetic effect on the resulting performances, which can further be evaluated and confirmed by series of electrochemical measurements.

•MnCo2O4.5 and MnNi6O8 nanoparticles have been synthesized by a simple coordination-polymer approach.•The capacitance retention of Mn/Co-600 electrode is more than 92.9% after 1000 continuous cycling.•MnCo2O4.5 nanoparticles exhibit excellent electrochemical performance.Two types of ternary metal oxides, MnCo2O4.5 and MnNi6O8 nanoparticles have been separately synthesized through chemical transformation from the corresponding bimetallic coordination polymer particles precursor under high-heating conditions. Series of electrochemical measurements are performed to examine the MnCo2O4.5 and MnNi6O8 electrodes, and the result shows that MnCo2O4.5 structure, especially for Mn/Co-600, has much higher capacitance than that of MnNi6O8 nanoparticles, indicating MnCo2O4.5 electrode is more suitable for applying in neutral electrolyte system. The Mn/Co-600 electrode exhibits a specific capacitance of 158 F g−1 at 5 mV s−1, good rate capability of 53.8% with a 20 times current density increase, good cycle performance (92.9% capacitance retention after 1000 cycles) and high power density (a specific power of 5760 W kg−1 at 4.0 A g−1) with low charge transfer resistance value of 1.8 Ω.

Two nanoscale metal–organic frameworks (NMOFs), namely Co–Im and Co–Py, have been firstly prepared in poor solvent through a precipitation method. XRD, TGA and EA results show that as-synthesized NMOFs are isostructural with the reported crystal structure of {[Co(H2IDC)2(H2O)2]·2DMF}n and {[Co(H2PDC)(PDC)]·3H2O}n molecules. High temperature calcining of these Co-based NMOFs can result in pseudo-capacitive Co3O4 electrodes. Series of electrochemical measurements indicated that the as-prepared Co3O4 material could deliver a maximum specific capacitance of 233 F g−1, good stability over 1500 cycles with the capacitance retention of 89.8% and low charge-transfer resistance of 1.22 Ω.Co3O4 nanoparticles are synthesized from annealing Co-based NMOFs and display pesudocapacitance behaviors, which can further be evaluated and confirmed by series of electrochemical measurements.

Three nanoscale Ni-Schiff-base coordination polymer particles have been firstly prepared in poor solvent (DMF) through a precipitation method. XRD, TGA and EA results show that as-synthesized compounds are either amorphous or crystalline. High temperature annealing of these Ni-based compounds can result in pseudo-capacitive NiO electrodes. Series of electrochemical measurements illustrated that the as-prepared NiO material, especially for NiO nanospheres could deliver a maximum specific capacitance of 153 F g−1 and good stability over 1000 cycles with the capacitance retention of 100%, indicating the morphology and resistance effect on the diffusion-controlled redox reaction between the OH− ions and the NiO samples.NiO nanostructures have been synthesized from Schiff-base building blocks. Among them, NiO nanospheres show higher capacitance than the other two electrodes with 100% retained capacitance after 1000 cycles at a constant scan rate.

High nitrogen-doped carbon/Mn3O4 composites were synthesized by annealing nitrogen-rich Mn-based coordination polymer particles, and investigated by electron microscopy, X-ray diffraction, and electrochemical experiments. To assess the performance of high nitrogen-doped hybrids as electrode materials in supercapacitors, cyclic voltammetry and galvanostatic charging–discharging measurements are performed. High nitrogen-doped carbon/Mn3O4 composites are charged and discharged faster and have higher capacitance than carbon/Mn3O4 nanostructures with low nitrogen amounts and other reported ones. The capacitance of the high nitrogen-doped carbon/Mn3O4 is 94% retained after 1000 cycles at a constant current. These improvements can be attributed to the nitrogen-doped carbon matrix, which promotes fast Faradaic charging and discharging of the Mn3O4 motifs. The nitrogen-doped carbon/Mn3O4 composites could be a promising candidate material for a high-capacity, low-cost, and environmentally friendly electrode for supercapacitors.

A facile approach for the fabrication of temperature-dependent NiO/Co3O4 composites, such as nanoparticles, mixed morphology and nanorod arrays, has been presented. The as-synthesized NiO/Co3O4 composites, especially for the uniform nanorod array structure, show a good rate capability even at high current densities and an excellent long-term cycling stability (more than 90% retained after 3000 cycles). This improvement can be attributed to the uniform morphology and synergistic effect of NiO and Co3O4 as individual constituents, which promote fast Faradaic charging–discharging reactions and act as an “ion reservoir” that can shorten the diffusion distance. These NiO/Co3O4 composites can be a promising candidate material for high-capacity and low-cost electrodes for supercapacitors.

•NiO nanoparticles of 19, 31 and 48 nm average diameter are synthesized from CPPs with different crystallinity.•Capacitance of NiO nanoparticles is size-dependent.•NiO nanoparticles exhibit wonderful capacitive properties.NiO nanoparticles of 19, 31 and 48 nm average diameter are synthesized by simple calcination of Ni-based coordination polymer precursors with different crystallinity, and are investigated for electrochemical energy storage. Electrochemical properties are firstly characterised by cyclic voltammetry (CV) and galvanostatic charge–discharge measurements; it is found that a specific capacitance of 140 F g−1 is achieved with the 19 nm NiO nanoparticles at 2.5 A g−1. Larger nanoparticles of 31 and 48 nm diameter exhibit specific capacitances of 114 and 101 F g−1, respectively, indicating a size-dependent capacitive performance enhanced with decreasing particles size, which is further be confirmed by the results of electrochemical impedance spectroscopy (EIS) and an endurance-life test.NiO nanoparticles of 19, 31 and 48 nm average diameter are synthesized and display a size-dependent capacitive performance enhanced with decreasing particles size, which can further be evaluated and confirmed by series of electrochemical measurements.

Wire-like coordination polymer architectures, coupled with polyvinylpyrrolidone (PVP) additive, have been synthesized under mild conditions. The morphology of the final coordination polymer was dependent on the synthetic parameters, such as solvents and the amount of PVP. A possible assembly mechanism for the composite nanowires, based on several characterization methods, has been proposed to interpret the growth process. In addition, the newly synthesized Ag-based polymer particles may act as novel antimicrobial agents and metal-based anticancer drugs in the future owing to their potent antibacterial and in vitro anticancer activities against the four selected cancer lines MCF-7, HeLa, H1299 and A549.

•Co-based coordination polymer particles with particles and nanoflake arrays shapes have been synthesized.•Co3O4 has been easily obtained by chemical transformation from CPPs.•C/CoO composites can be generated through transformation method in N2 atmosphere.•Co3O4 exhibit wonderful capacitive performance.A straightforward approach has been developed to fabricate Co3O4 nanostructures based on hollow-structured coordination polymer precursors, which have been synthesized from Co2+ and organic building blocks. The coordination polymer precursors and the transformation products have characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). The pseudo-capacitive behavior of Co3O4 nanostructures has been conducted by cyclic voltammetry, galvanostatic charge–discharge studies and electrochemical impedance spectroscopy. The result suggests that porous Co3O4 rods have smaller charge transfer resistance and faster ion diffusion rate in comparison with Co3O4 particles, and show better cycle properties at charging–discharging intensity of 3 A g−1.Co3O4 nanostructures are synthesized from annealing the uniform Co-based coordination polymer particles and display a pesudocapacitance behavior, which can further be evaluated and confirmed by series of electrochemical measurements.

High nitrogen-doped carbon/Mn3O4 composites were synthesized by annealing nitrogen-rich Mn-based coordination polymer particles, and investigated by electron microscopy, X-ray diffraction, and electrochemical experiments. To assess the performance of high nitrogen-doped hybrids as electrode materials in supercapacitors, cyclic voltammetry and galvanostatic charging–discharging measurements are performed. High nitrogen-doped carbon/Mn3O4 composites are charged and discharged faster and have higher capacitance than carbon/Mn3O4 nanostructures with low nitrogen amounts and other reported ones. The capacitance of the high nitrogen-doped carbon/Mn3O4 is 94% retained after 1000 cycles at a constant current. These improvements can be attributed to the nitrogen-doped carbon matrix, which promotes fast Faradaic charging and discharging of the Mn3O4 motifs. The nitrogen-doped carbon/Mn3O4 composites could be a promising candidate material for a high-capacity, low-cost, and environmentally friendly electrode for supercapacitors.