A Pair of Rare Three-Dimensional Chiral Polyoxometalate-Based Metal–Organic Framework Enantiomers Featuring Superior Performance as the Anode of Lithium-Ion Battery

Two rare three-dimensional (3D) chiral polyoxometalate-based metal–organic framework (POMOF) materials, d - [PMo 8 V Mo 4 VI O 37 (OH) 3 Zn 4 ][BPP] 2 ·2[pyridine]·H 2 O ( d - 1 ) and l -[PMo 8 V Mo 4 VI O 37 (OH) 3 Zn 4 ][BPP] 2 ·2[pyridine]·H 2 O ( l - 1 ) (BPP = 1,3-bis(4-pyridyl)propane) were prepared with achiral ligand under solvothermal conditions. They are the first 3D chiral POM-based frameworks based on a Zn-ε-Keggin unit and achiral ligands. The CD spectra and structural analyses indicate that the two polyoxometalate-based metal–organic frameworks are enantiomers. The alternate connection of Zn-ε-Keggin cluster and BPP ligands generate helical infinite chains, while each single spiral chain is further interlinked to adjacent neighboring units to produce a 3D regular ordered chiral architecture with a qtz topology. Compound 1 (mixtures of d - 1 and l - 1 ) exhibited excellent stability in both acid and base aqueous solutions. When compound 1 was used as an anode electrode material of rechargeable Li-ion batteries (LIBs), outstanding reversible capacity of 1004 mA h g –1 was obtained after 100 cycles along with cycle stability and outstanding rate performance. Such a high reversible capacity has previously never been reported for the LIB anodes within the pristine POM-based crystals.