Manganese oxide/carbon yolk-shell nanorod anodes for high capacity lithium batteries.

ABSTRACT

Transition metal oxides have attracted much interest for their high energy density in lithium batteries. However, the fast capacity fading and the low power density still limit their practical implementation. In order to overcome these challenges, one-dimensional yolk-shell nanorods have been successfully constructed using manganese oxide as an example through a facile two-step sol-gel coating method. Dopamine and tetraethoxysilane are used as precursors to obtain uniform polymer coating and silica layer followed by converting into carbon shell and hollow space, respectively. As anode material for lithium batteries, the manganese oxide/carbon yolk-shell nanorod electrode has a reversible capacity of 660 mAh/g for initial cycle at 100 mA/g and exhibits excellent cyclability with a capacity of 634 mAh/g after 900 cycles at a current density of 500 mA/g. An enhanced capacity is observed during the long-term cycling process, which may be attributed to the structural integrity, the stability of solid electrolyte interphase layer, and the electrochemical actuation of the yolk-shell nanorod structure. The results demonstrate that the manganese oxide is well utilized with the one-dimensional yolk-shell structure, which represents an efficient way to realize excellent performance for practical applications.