The keys for effective distribution of intergranular voids of peapod-like MnO@C core-shell for lithium ion batteries

Abstract

Conversion reaction-based transition metal oxides have shown high reversible capacity compared to conventional intercalation reaction-based materials. However, their practical applications have been impeded by a poor cycle life resulted from their low electrical conductivity and huge volume changes. During the past decade, remarkable advances have been achieved in the preparation of nanostructured transition metal oxides for conversion reaction anodes. Among the various shaped nanomaterials, core-shell structure with a carbon shell showed excellent electrochemical performance. Herein, we prepared peapod-like MnO@C nanowires as one special type of core-shell structure, and we elucidated the structure-properties relationship in peapod-like MnO@C nanowires for Li-ion batteries. The morphology of the manganese oxide particles inside the carbon layer could be simply controlled by adjusting the parameters in the carbonization process. The optimized composites exhibited excellent cycling performance without decreasing the capacity, and outstanding rate properties. The optimized structure can maximize the advantages such as structural durability against the stress involving huge volume changes, as well as minimize the side reaction at the surface.