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- [PMo₈^VMo₄^VIO₃₇(OH)₃Zn₄]­[BPP]₂·2­[pyridine]·H₂O (d-1) and l-[PMo₈^VMo₄^VIO₃₇(OH)₃Zn₄]­[BPP]₂·2­[pyridine]·H₂O (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.