Effect of Polypyrrole Coating on Lithium Storage for Hollow Sb Microspheres

In this work, we synthesize hollow Sb microspheres (Sb HMSs) coated with polypyrrole (PPy) film (PPy@Sb HMSs) via a replacement reaction and ultrasound-assisted chemical polymerization. Using the synthesized PPy@Sb HMSs as electrode material in lithium-ion battery (LIB) cells, we study the electrochemical performance of the LIB cells. The LIB cells with PPy-20@Sb HMSs as the active material in the working electrode deliver a higher reversible capacity of 418.3 mAh g−1 after 100 cycles than 305.4 mAh g−1 of the LIB cells with Sb HMSs as the active material in the working electrode after 70 cycles at a current density of 0.1 A g−1, while the reversible capacity of the LIB cells with PPy-25@Sb HMSs as the active material in the working electrode is smaller than that of the LIB cells with Sb HMSs as the active material in the working electrode under the same cycling conditions. PPy coating on Sb HMSs can improve the cycling stability of Sb HMSs since PPy functions as a barrier to ensure the formation of a stable layer of solid electrolyte interphase; PPy coating of a large amount on Sb HMSs causes the decrease of specific capacitance due to smaller specific capacitance of PPy than Sb.