ReS_2 nanosheets anchored on rGO as an efficient polysulfides immobilizer and electrocatalyst for Li-S batteries

摘要

Transition metal dichalcogenides (TMDs) have been widely studied as a promising sulfur host material in Li-S batteries due to their unique physical and chemical properties. Great efforts have been made to prepare carbon/TMDs, especially graphene/TMDs heterostructures as the cathodes of Li-S batteries. Recently, ReS2 shows a new 1T' phase and great potential in Li-S batteries because of its stable structure and a large amount of catalytic active sites. Herein, we prepared a new ReS2 nanosheets anchored on rGO (rGO/1T'-ReS2) composite as a lithium polysulfides (LiPSs) immobilizer and electrocatalyst for Li-S batteries. The unique pore structure and rGO incorporation can effectively mitigate volume expansion and enhance electronical conductivity. Moreover, the novel 1T' phase of ReS2 shows both efficient chemical adsorption function and large electrocatalytic active sites of LiPSs. These advantages have been demonstrated by both characterization techniques and theoretical calculations. As a result, the rGO/1T'-ReS2/S nanosheets display significantly enhanced coulombic efficiency, rate performance and cycling stability compared with the rGO/S nanosheets and the rGO/1T'-ReS2/S nanospheres.