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

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.

Automated summary

Four new polyoxometalate-based metal-organic frameworks were synthesized and characterized using single crystal X-ray diffraction. These materials exhibit good electrochemical performance in lithium ion batteries, with stable reversible capacities and excellent rate performance.