Decoration of indium tin oxide nanoparticles with different crystal structures and morphologies on polypropylene separator for Li‐S battery

Abstract

A variety of materials have been applied for the modification of cathode or separator for lithium-sulfur batteries so as to overcome the intrinsic problems of lithium-sulfur batteries. Here, indium tin oxide with different crystal structures and morphologies has been used for the modification of commercial polypropylene (PP) separators for lithium-sulfur batteries to prohibit the polysulfides shuttle and promote the Li-S cell performances. Indium tin oxide with cubic bixbyite (c-ITO) and hexagonal corundum (h-ITO) are firstly fabricated by different hydrothermal reactions and then coated on PP separator to obtain c-ITO@PP and h-ITO@PP separators. Then, c-ITO@PP and h-ITO@PP separators are used in Li-S coin cells to improve the electrochemical properties. The experimental data suggest that the cells equipped with c-ITO@PP or h-ITO@PP modified separator exhibit better electrochemical performances than the cell with unmodified PP separator and super P modified separator, which demonstrate that the c-ITO and h-ITO show better polysulfides adsorption ability than the pure carbon materials. Furthermore, the cycle retention of the Li-S cell using h-ITO@PP separator is superior than that of the one using c-ITO@PP separator. This result is supposed to be mainly induced by the more oxygen vacancies in h-ITO which is proved by the X-ray photoelectron spectroscopy study, and the UV-vis spectroscopy of Li2S6 adsorption further demonstrate the better polysulfides adsorption ability of h-ITO.