Effects of low-temperature carbon encapsulation on the electrochemical performance of SnO2 nanopowders

Carbon encapsulated SnO2 composites were prepared by a thermal evaporation and decomposition of malic acid (C4H6O5) at low temperature to demonstrate their potential use for application in lithium ion batteries. The solution-based chemical approach was effective for coating amorphous C layers on the surface of SnO2 nanopowders without significant oxygen reduction. The desirable crystalline structure and oxygen stoichiometry of SnO2 were maintained, while amorphous C homogeneously encapsulated SnO2 nanopowders. The strong enhancement on the anodic reversible capacity and cyclic performance was discussed for the C-encapsulated SnO2 composites. It is expected that the low-temperature processing can be a new general route for preparing composites with C from economic point of view.