Surfactant-assisted fabrication and supercapacitor performances of a 12-phosphomolybdate-pillared metal–organic framework containing a helix and its SWNT nanocomposites

Abstract

A new polyoxometalate-pillared metal–organic framework crystalline compound with multi-fold helical chains, [Ni₇(1,2,4-tri)₁₂(H₂O)₁₀][HPMo₁₂O₄₀]·10H₂O (NiPMo₁₂), was successfully synthesized by a surfactant-assisted hydrothermal method for the first time and characterized by single crystal X-ray diffraction analyses, IR, PXRD, Raman spectroscopy, SEM and TEM. Further, combination of the reversible multi-electron redox behaviours and electron storage performances of NiPMo₁₂ with the good electrical conductivity of single-walled carbon nanotubes (SWNTs) gives the NiPMo₁₂/SWNTs nanocomposite excellent electrochemical performance and stability as an electrode material for supercapacitors (SCs), and the NiPMo₁₂/SWNTs nanocomposite has a specific capacity of ca. 815.6 F g⁻¹ at a 1 A g⁻¹ current density and cycling stability with 96.5% specific capacitance after 6000 cycles in 2 M H₃PO₄. The successful surfactant-assisted syntheses of POM-based crystalline materials or their nanocomposites might attract extensive research interest for developing new high-performance electrode materials for SCs.