One-step synthesis of nano-S/C@PANI composites for lithium-sulfur batteries with high rate and long lifespan

Abstract

Conductive polymers in combination with carbon matrix are an effective way for the confinement of lithium polysulfides and improved conductivity of sulfur. It can advance the commercial application of lithium-sulfur batteries to optimize preparation methods of conductive polymers in combination with carbon matrix in the process of loading sulfur. Here, a S/C@PANI composite is synthesized via an in situ one-step synthesis method using graphite as a conductive carrier and polyaniline as a conductive polymer. The effect of different preparation methods on the property of the as-prepared S/C@PANI composite is investigated. The S/C@PANI composite prepared via the one-step method delivers a specific capacity of 984 mA h g−1 at 0.1 C, especially 404 mA h g−1 at a high rate of 3 C, and maintains a discharge capacity of 465 mA h g−1 after 200 cycles at 0.5 C, responding to a capacity retention of 77.3%, showing excellent rate capability and good cycling performance. These exceptional performances are attributed to the booted electron transport pathways and suppressed shuttle effect of polysulfides resulting from the strengthening covalent coupling between polyaniline and graphite via one-step assembly synthesis. The one-step synthesis method used in this work offers a facile and efficient route for applying Li/S batteries.