Casting amorphorized SnO ₂ /MoO ₃ hybrid into foam-like carbon nanoflakes towards high-performance pseudocapacitive lithium storage

We report an amorphorization-hybridization strategy to enhance lithium storage by casting atomically mixed amorphorized SnO ₂ /MoO ₃ into porous foam-like carbon nanoflakes (denote as SnO ₂ /MoO ₃ @CNFs, or SMC in short), which are simply prepared by annealing tin(II)/molybdenum(IV) 2-ethylhexanoate within CNFs under ambient atmosphere at a low temperature (300 °C). The SnO ₂ /MoO ₃ loading amount within CNFs can be easily adjusted by controlling the Sn/Mo/C precursors. When examined as lithium ion battery (LIB) anode materials, the amorphorized SnO ₂ /MoO ₃ @CNFs with carbon content of 32 wt% (also denote as SMC-32, in which the number represents the carbon content) deliver a high reversible capacity of 1120.5 mA h/g after 200 cycles at 200 mA/g and then 651.5 mA h/g after another 300 cycles at 2000 mA/g, which is much better than that of the crystalline SnO ₂ /CNFs (carbon content of 34 wt%), MoO ₃ /CNFs (carbon content of 22.7 wt%), or SnO ₂ /MoO ₃ @CNFs (with lower carbon contents of 11 and 25 wt%). The electrochemical measurements as well as the ex situ structure characterization clearly suggest that combination of amorphorization and hybridization of SnO ₂ /MoO ₃ with CNFs synergistically contributes to the superior lithium storage performance with high pseudocapacitive contribution.