International Journal of Energy Research, Vol.45, No.4, 6002-6014, 2021
Enhanced performance of Li-S battery by constructing inner conductive network and outer adsorption layer sulfur-carbon composite
A liquid phase deposition method is performed to prepare acetylene black/sulfur (AB/S) composites, and in-situ polymerization is utilized to synthesize polypyrrole (PPY) on the surface of AB/S. The coral-like structured AB provides huge micropores and vast specific surface area for bonding sulfur, and supplies a 3D conductive matrix for enhancing the conductivity of composite. A plenty of ion channels served by PPY layer can promote the Li+ migration and alleviate the electrode polarization. In addition, the dissolution and diffusion of lithium polysulfides in the electrolyte can be restrained by PPY coating. The volume variation of cathode in the charge-discharge process can be relieved by the high elastic PPY layer combined with the 3D matrix of AB. The Li-sulfur battery (LSB) with the AB/S@PPY cathode exhibits an extraordinary cycle stability and rate adaptability with the specific capacities of 1207.1 mAh g(-1) at the initial discharge process and 884.4 mAh g(-1) even after 100 cycles at 0.2 C. Furthermore, an excellent specific capacity of 675.3 mAh g(-1) has been delivered by the AB/S@PPY electrode at a high discharge rate of 2 C.