Polyoxometalate-based Cu/Zn-MOFs with diverse stereo dimensions as anode materials in lithium ion batteries

Abstract Four new polyoxometalate-based metal-organic frameworks (POMOFs) of NAU3–6 with various architectural structure features have been prepared through hydrothermal methods, and characterized by single crystal X-ray diffraction. Based on semblable 1D hamburger chains, NAU3 and 4 show 3D and 2D supramolecular networks due to the Van der Waals' forces by altering polyoxometalate anions. When the same SiW12O404− anions and disparate metal centers are employed in NAU5 and 6, NAU5 shows a fascinating 2D layer constructed by 1D folded chains, and NAU6 displays a 2D pillared layer with polyoxometalate anions as pillars. Directly employed the four crystalline POMOFs as the anode materials in lithium ion battery (LIB), NAU3–6 give obvious electrochemical performance divergences and the reversible capacities maintain stable at 575.8, 435.5, 314.8 and 362 mA h g−1, respectively. The NAU3 shows a high initial and reversible capacity of 1406.4 and 575.8 mA h g−1 at the current density of 100 mA g−1, especially providing an excellent rate performance of 58.1% at 1000 mA g−1. Further, the lithium storage mechanisms based on diverse structural features have also been meticulously investigated.