Two nanoscale Nb containing polyoxometalates based on {PWNbO} clusters and chromium cations.

Two novel mixed-addenda Nb/W polyoxometalates are successfully fabricated, and investigated as anode materials for lithium-ion batteries. For the CsK{Cr(HO)[PWNbO]}·60HO sample, a reversible capacity (466.6 mA h g) and stable cycle performance are obtained.