3D pill-structured Ti-MOF@S composite cathodes for high-performance Li–S batteries

Abstract

Li–S batteries are gaining increasing popularity because of their outstanding benefits, namely, low cost, large theoretical capacity, and high theoretical energy density. However, the strong “shuttle phenomenon” of lithium polysulfides significantly reduced the performance and hampered commercial applications of Li–S batteries. Herein, a novel 3D pill-structured Ti-MOF@S composite with a stable framework was developed. The stable framework can inhibit large volume expansion of sulfur during the lithiation process to prevent the collapse of the cathode structure. The inherent rich porous structure of the Ti-MOF can adsorb the polysulfides to alleviate the “shuttle phenomenon”. When the 3D porous Ti-MOF@S composite was used as a cathode of Li–S batteries, it showed an outstanding initial capacity of 1249 mA h g⁻¹ at 0.5C and good reversibility of 99.9% coulombic efficiency after 100 cycles.