Design and Evaluation of a Three Dimensionally Ordered Macroporous Structure within a Highly Patterned Cylindrical Sn-Ni Electrode for Advanced Lithium Ion Batteries

A 3-dimensionally ordered macroporous (3DOM) structure within a highly patterned cylindrical Sn-Ni alloy electrode was tailored by using various monodispersed polystyrene (PS) templates via a colloidal crystal templating process coupled with an electroplating process. The pore size and the wall thickness in the inverse opal 3DOM structure were increased with increasing the size of the PS template beads used in this study. The electrochemical performance of prepared electrodes was examined in order to reveal the correlation between the rate capability and the 3DOM structure. Except the electrode with 1.2 mu m pores, the discharge capacities gradually decreased with increasing the current density, showing a capacity conservation ratio of 87% for the electrode with 0.5 mu m pores and that of 84% for the electrode with 3.0 mu m pores when the current density increased from 0.05 mA cm(-2) to 2.0 mA cm(-2). The reason for this difference is attributed to the fact that the wall thickness of less than 0.5 mu m in the electrode with 1.2 mu m pores has a short Li+ diffusion distance in solid-state walls. In addition, it is expected that high regularity of 3DOM structure plays a great role on rate capability. Consequently, the 3DOM structure prepared from 1.2 mu m PS template beads was favorable for improving the rate capability.