Perovskite quantum dots Revolutionize Lithium-Sulfur battery Performance: Cathode catalytic Breakthrough with CsPbBr3

Abstract

Lithium-sulfur batteries (LSBs) are considered one of the most promising energy storage devices, but some challenges such as the low conductivity of the sulfur cathode and the shuttle effect of polysulfides have hindered their commercialization. Here, we have developed a composite catalytic material (PTI-CsPbBr₃) with CsPbBr₃ halide perovskite quantum dots loading on a polyaniline (PANI) modified with TiO₂ (PTI) substrate as the sulfur host for the LSB. CsPbBr₃ perovskite quantum dots (CsPbBr₃ QDs), as nanoscale perovskite materials, combine the inherent excellent charge transport properties and structural stability of perovskite with the unique size and surface effects of quantum dots. The special octahedral framework structure results in a large number of unsaturated coordination sites on the surface, creating abundant active centers which is beneficial for enhancing the catalytic activity of the material. Moreover, the small size of CsPbBr₃ QDs effectively mitigates the significant polarization issues caused by larger grain sizes in traditional perovskite materials so as to exhibit excellent interactions with lithium polysulfides (LiPSs). Then, they can significantly reduce the activation energy of LiPSs decomposition reactions in order to accelerate the conversion reaction rate of LiPSs. Therefore, the PTI-CsPbBr₃/S composite cathode at a ratio to 30:1 exhibits excellent LiPSs adsorption and catalytic properties for high-performance lithium-sulfur batteries. Even at a high sulfur loading (6 mg·cm⁻²) and a current density of 0.5C, it still remains stable for 500 cycles with a capacity attenuation rate of only 0.15 % for a single cycle.