Facile synthesis and performance of polypyrrole-coated hollow Zn ₂SnO₄ boxes as anode materials for lithium-ion batteries

Polypyrrole-coated hollow Zn₂SnO₄ boxes (hollow Zn₂SnO₄@PPY nanocomposites) had been prepared by a microemulsion polymerization. The structural, morphological and electrochemical properties were methodically investigated by means of XRD, TGA, BJH (pore size distribution analysis), SEM, TEM, and electrochemical measurements. Results show that the hollow Zn₂SnO₄ boxes with the uniform and cube like structure are coated by PPY. Electrochemical measurement suggests that hollow Zn₂SnO₄@PPY composites exhibit better cycling properties and lower initial irreversible capacities as anode materials for lithium-ion batteries. At a current density of 60 mA/g in the voltage about 0.01-3.0 V, the first discharge-charge capacities of hollow Zn ₂SnO₄@PPY composites are 1105.2 mAh/g and 556 mAh/g. After 50 cycles, a specific charge capacity of 478.4 mAh/g remained and the coulombic efficiency reaches 98.2%, revealing better capacity retention compared with hollow Zn₂SnO₄ boxes.