Enhancing the electrochemical performance of micron-scale SiO@C/CNTs anode via adding piezoelectric material BaTiO3 for high-power lithium ion battery

Abstract

Silicon monoxide (SiO)-based negative materials have attracted widespread attention due to the low working potential and high specific capacity. However, the large volume dilation (about 200%) is adverse to the electrochemical performance of battery during the charge-discharge process. To overcome the disadvantage of volume change, much effort has been paid to minimize the volume expansion. Unfortunately, the volume change is inescapable no matter how to modify the SiO-based materials. Therefore, utilizing the characteristics of volume expansion to improve the electrochemical properties of SiO-based material is the most desirable method. Piezoelectric materials can generate local piezoelectric field when suffer from the mechanical stress, which serves as a driving force to accelerate the transmission speed of Li ion, result in the improve of electrochemistry performance. In this work, SiO@C/BaTiO3/Carbon nanotubes composites are successfully synthesized and served as anode materials for lithium ion batteries (LIBs). The SiO and BaTiO3 are dispersed uniformly in amorphous carbon matrix, the large volume expansion of SiO can transfer to the BaTiO3 via the carbon matrix. When the BaTiO3 nanoparticles poled, the piezoelectric potential is generated, which can promote the mobility of Li ion. Carbon nanotubes provides the transmission channel to accelerate the diffusion of Li ion, which is benefited to the constitution and structure of composite, the SiO@C/BaTiO3/Carbon nanotubes exhibit excellent electrochemical performance with a high charge capacity of 711 .7 mAh g−1 and a high capacity retention of 92.4% after 200 cycles at 100 mA g−1. Experimental results suggest that the piezoelectric material BaTiO3 can enhance the electrochemical properties of SiO-based materials.