Zn-MOF derived micro/meso porous carbon nanorod for high performance lithium–sulfur battery

Abstract

In order to solve the problems of poor cycling stability and low coulombic efficiency in lithium–sulfur battery, induced by the low conductivity of sulfur and the shuttle effect of soluble polysulfides, a unique micro/meso porous carbon nanorod (MPCN) was fabricated by carbonizing a zinc metal–organic framework (Zn-MOF) precursor, which was prepared by a facile aqueous solution method at room temperature. The mesopores in the MPCN are beneficial for the infiltration of electrolyte and the transportation of Li ions, and the micropores are sufficient to encapsulate sulfur and adsorb the soluble polysulfides. The MPCN–S cathode displays a discharge capacity of about 1000 mA h g⁻¹ at the current rate of 0.5C and retains 740 mA h g⁻¹ after 200 cycles with the coulombic efficiency up to 95%. Moreover, it still has a discharge capacity as high as 850 mA h g⁻¹ when the current rate increased to 2C, which demonstrates a nice rate capability.