Synthesis of two new polyoxometalate-based organic complexes from 2D to 3D structures for improving supercapacitor performance.

As an emerging energy-storage technology, research on supercapacitors is vital for advancing new energy applications, which rely on the development of electrode materials with superior properties. In this study, two novel polyoxometalate-based metal-organic complexes (POMOCs), Ag(imbta)(PMoMoO) (PMo-Ag-imbta, 1) (imbta = 1-imidazole-1-methylene-1-benzotriazole) and Ag(pybta)(PMoMoO)(PMo-Ag-pybta, 2) (pybta = 1-pyridine-3-methylene-1-benzotriazole), were synthesized a hydrothermal method utilizing Ag, imbta/pybta and [PMoO], respectively. In 1, Ag, imbta, and [PMoO] form 2D layers coordination bonds. At the same time, Ag forms a 1D chain with [PMoO]. In 2, Ag and pybta form four separate Ag-pybta spiral chains. In addition, the coordination interaction between Ag and [PMoO] not only induces the construction of the Ag-PMo 2D network that promotes electron transport in 2 but also facilitates the development of the 3D structure characterized by the four-helix winding. Meanwhile, there are many holes in 2, which are conducive to ion transport. In a three-electrode system, 2-GCE demonstrated superior capacitive performance (668 F g at 1 A g) compared to 1-GCE (420 F g at 1 A g), along with excellent cycling stability (91.4% retention after 1000 cycles). Notably, the specific capacitance of 2-GCE at 5 A g was four times higher than that of PMo. This study advances the development of novel crystalline electrode materials for energy storage applications.