Porous structure of fixed sulfur and networked electronic channels in three-dimensional skeletal structure of polyaniline and MOF-derived materials

Abstract

Lithium-sulfur batteries (LSBs) are favored for their high specific capacity and energy density, but they have problems, such as electrode volume expansion and poor electrical conductivity, that need to be solved. In this work, a three-dimensional (3D) interconnection network structure (3CPC) material was designed and synthesized from the composite of polyaniline (PANI) and metal–organic-skeleton-derived nitrogen carbon (NC). PANI conductive fiber acts as a bridge between NC and insulating sulfur to promote electron transfer. A large number of mesopores and micropores in the 3D spatial network structure effectively fixed sulfur. Results show that the 3CPC@S cathode materials have excellent electrochemical properties. The initial discharge-specific capacity of the 3CPC@S cathode material reached 1220.1 mAh g−1 at a current density of 0.1 C. Its reversible capacity was 1018.7 mAh g−1 after 100 cycles, corresponding to a capacity retention rate of 83.5%. The material frame was used to provide electronic channels, and the physical structure was combined to carry out sulfur fixation to improve the electrochemical performance of the cathode material. This method provides a new idea for improving the volume expansion and conductivity of LSB electrode.