Polyoxotungstates-supported NiII/CoII-containing 3D inorganic-organic hybrids as supercapacitor electrodes toward boosting capacitor performance

Abstract Herein, five new polyoxotungstates (POTs)-based NiII/CoII-containing 3D inorganic-organic hybrid compounds, [H5(SiW9VIW3VO40)3Ni8(H2O)12(atrz)12]·12H2O (SiW12-Ni8), [H2(PW9VIW3VO40)3Ni8(H2O)12(atrz)12]1/3·4H2O (PW12-Ni8), [H11(CoW9VIW3VO40) 3Ni8(H2O)12(atrz]12]·12H2O (CoW12-Ni8), [H11 (CoW9VIW3VO40) 3Co8(H2O)12(atrz)12]·12H2O (CoW12-Co8), [H2(PW9VIW3VO40)3Co8(H2O)12(atrz)12] 1/3·4H2O (PW12-Co8) (atrz = 4-amino-1,2,4-triazole) have been synthesized via hydrothermal reaction and explored as pseudocapacitive electrode materials. Single-crystal X-ray diffraction displays these compounds have isostructural three-dimensional (3D) configuration and possess a (3,4)-connected (83)4(72. 82)3 topology structrue. Compared to others, CoW12-Ni8 as electrode materials shows the highest specific capacitance (526.1 F g−1 at 1.0 A g−1) and only experiences 16% capacitance loss at a high charge/discharge current density of 10 A g−1 after 1000 cycles. The capacitance ability of these POTs-based compounds is mainly dominated by the substituted heteroatoms (Co, Si, or P) in POTs and the coordinated metal (NiII or CoII) in the adjacent building blocks. This work may develop a new path to optimize the performance of POTs-based energy functional materials.