A multi-functional model based on confined assembly of polyaniline on the surface of multiwalled carbon nanotubes as framework for high-performance lithium-sulfur battery

Abstract

Lithium-sulfur (Li-S) battery is one of the most promising energy storage devices but suffer from insufficient cyclability and low utilization of sulfur caused by insulative nature of sulfur and the shuttle effect of Li-S battery. To address the abovementioned issues, a strategy based on confined assembly of polyaniline (PANI) on multiwalled carbon nanotubes (MWNTs) drive by the π-π electronic interaction is proposed to prepare MWNTs@PANI model. Benefit from the doping characteristic of PANI, various multifunctional dopants can be introduced to adjust the aggregation structure of PANI and construct a functionally improved model, and most importantly, the various functional groups of dopants provide an extra boost for suppression of the shuttle effect. Benefit from the unique microstructure and multi-functional groups, the cathode based on MWNTs@PANI model delivers the initial discharge capacity of 1309 mAh g−1 at 0.1C, and exhibits a stable capacity of 672 mAh g−1 even after cycling for 250 times at 1C. The assembled soft-packed cell shows an ultrastable open-circuit voltage at various bending states. These results indicate that the MWNTs@PANI model can easily introduce various functional groups to address the challenge from the shuttle effect, which is supposed to accelerate the practical progress of high-performance Li-S battery.