Synthesis of spherical porous carbon by spray pyrolysis and its application in Li-S batteries

摘要

A spherical porous carbon (SPC) with high specific surface area is prepared by spray pyrolysis at 800 °C followed by removing silica template. The prepared SPC is employed as a conductive matrix in the sulfur cathode (S-SPC) for lithium-sulfur secondary batteries. The BET surface area of the prepared SPC sample is as high as 1,133 m~2 g~(-1) and the total pore volume is 2.75 cm~3 g~(-1). The electrochemical evaluations including charge-discharge tests, cyclic voltammograms (CV), and electrochemical impedance spectrum suggest that the prepared S-SPC composite presents superior electrochemical stability when compared to the S-SP cathode. The as-prepared S-SPC composite shows improved cycle performance. The reversible discharge capacity is about 637 mAh g~(-1) after 50 cycles, which is much better than that of the as-prepared sulfur-Super P carbon black composite. Itmay be attributed to the high porosity and excellent conductive structure of the SPC.