Polyoxomolybdate-Polypyrrole/Reduced Graphene Oxide Nanocomposite as High-Capacity Electrodes for Lithium Storage

A nanocomposite polyoxomolybdate (PMo₁₂)-polypyrrole (PPy)/reduced graphene oxide (RGO) is fabricated by using a simple one-pot hydrothermal method as an electrode material for lithium-ion batteries. This facile strategy skillfully ensures that individual polyoxometalate (POM) molecules are uniformly immobilized on the RGO surfaces because of the wrapping of polypyrrole (PPy), which avoids the desorption and dissolution of POMs during cycling. The unique architecture endows the PMo₁₂-PPy/RGO with the lithium storage behavior of a hybrid battery-supercapacitor electrode: the nanocomposite with a lithium storage capacity delivers up to 1000 mAh g^-1 at 100 mA g^-1 after 50 cycles. Moreover, it still demonstrates an outstanding rate capability and a long cycle life (372.4 mAh g^-1 at 2 A g^-1 after 400 cycles). The reversible capacity of this nanocomposite has surpassed most pristine POMs and POMs-based electrode materials reported to date.