Flower-like Bi4Ti3O12/Carbon nanotubes as reservoir and promoter of polysulfide for lithium sulfur battery

Abstract

Lithium-sulfur battery (LSB) is considered as the candidate of the new generation of rechargeable power conservation equipment due to its preferable theoretical specific energy and theoretical energy density. However, LSB is constrained by their inherent shortcomings containing notorious shuttle effect and poor conductivity of sulfur and discharge products (Li2S/Li2S2). In order to overcome these obstacles, flower-shaped bismuth titanate embedded with carbon nanotubes (BTO/CNT) is designed as efficient sulfur host materials. The BTO/CNT composites can provide abundant voidage to support the sulfur, and its large contact surface can accelerate the catalytic transformation of lithiumsulfide. Importantly, bismuth titanate (BTO) as ferroelectric materials can spontaneously polarize to induce an inner electric field, which can not only accelerate the lithium polysulfides (LiPS) conversion due to its catalytic activity, but also enhance the chemical interaction for heteropolar LiPS based on the Lewis acid and bases interaction to alleviate the shuttle effect of LSB. Furthermore, the embedded CNT constructs a conductive network greatly improving electrode electrical conductivity. In view of these advantages, BTO/CNT as sulfur host delivers impressive cyclic stability with attenuation rate of 0.037% per cycle capacity over 1000 cycles with sulfur loading around 1.0 mg cm−2 at 1 C, suggesting enormous potential for excellent-performance Li–S batteries.