Authors: Meiri Wang Huamin Zhang Yining Zhang Jing Li Fengxiang Zhang Wen Hu
Publish Date: 2013/04/25
Volume: 17, Issue: 8, Pages: 2243-2250
Abstract
A hierarchical porous carbon material as the conductive matrix in the sulfur cathode for rechargeable lithium batteries is prepared by an in situ twostep activation method using sucrose as the carbon source CaCO3 as the template and CH3COO2Cu·H2O CuAc2 as the additive The microstructure and morphology of the activated porous sulfur–carbon composite is characterized by means of Xray diffraction N2 adsorption–desorption and scanning electron microscopy The functioning mechanism of the additive on the pore formation is investigated using thermogravimetric analysis Our results establish that thermal decomposition of the nanoCaCO3 template results in the formation of the hierarchical porous carbon structure and addition of CuAc2 influences the carbonization process in an unhomogeneous way through the copper ion–sucrose reaction resulting in the volume increment of small mesopores The sample obtained shows better sulfur dispersion in the active porous carbon than that synthesized without CuAc2 involvement which is attributable to the modified pore structure and enlarged pore volume Thus a better utilization of sulfur is achieved and the initial discharge capacity increases from 1287 to 1397 mAh g−1 Furthermore the LiS battery shows improved cycle stability because of enhanced interaction between the sulfur and the small mesopore
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