Graphite-like polyoxometalate-based metal–organic framework as an efficient anode for lithium ion batteries

Abstract

A new polyoxometalate (POM) pillared metal–organic framework (POMOF), [Cu₂₄(Trz)₁₆(H₂O)Cl₄(HPMo₁₂O₄₀)] (Cu-POM, Trz = 1,2,3-triazole), was synthesized and characterized. Crystal analysis reveals that the Keggin POMs are inserted into copper–triazole layers with a graphite-like structure generating a POM-supported porous three-dimensional framework. Owing to the combination of the multi-electron redox property of POM units and the open porous framework, Cu-POM can be utilized as an anode material for lithium ion batteries (LIBs), and exhibits a reversible capacity of 525 mA h g⁻¹ at a current density of 100 mA g⁻¹ after 100 cycles. Moreover, to illustrate lithium storage, the impedance spectra of compound Cu-POM during the first and 100th charge process have also been studied. The study of Cu-POM in this work might guide the development of POM-based electrode materials for LIBs.