Preparation of lamellar carbon matrix for sulfur as cathode material of lithium-sulfur batteries

Sulfur is a promising cathode material for lithium batteries as it has high theoretical specific capacity and low cost. However, practical electrochemical performance of lithium-sulfur batteries needs to be improved. In this work, a new method is described to prepare carbon matrix for sulfur to improve electrochemical properties of sulfur electrodes. The carbon matrix is prepared by deoxidizing carbon precursor synthesized by carbonizing sucrose with concentrated sulfuric acid. Carbon matrix-sulfur composite has been characterized by scanning electron microscopy, transmission electron microscopy and Fourier transform infrared. Results indicate that carbon matrix-sulfur composite is composed of lamellas. The lamella contains a layer of carbon coating on the outside and chemical bonds of C-S. The formation of C-S bonds is promoted by deoxidizing carbon precursor. The carbon matrix-sulfur electrode exhibits improved discharge properties, which results from the appropriate structure. Carbon coating and C-S bonds confine sulfur and maintain contact between sulfur species and conductive carbon matrix.