Free-standing N-doped carbon cathode for Li-S battery.

Abstract

A free-standing carbon cathode is attractive in that it can increase the proportion of active material without any current collector, conductive material, and binder. This study introduces a free-standing carbon cathode derived from CO2 with very high porosity for lithium-sulfur battery. The free-standing carbon cathode, while having its very porous structure, shows very excellent elasticity, providing potential as a standalone electrode material in industry. In addition, in the process of making free-standing carbon through electrospinning of polyacrylonitrile (PAN) and NaBH4, the very rich N atoms, 19.38wt% of pyridinic N and 16.24% of pyrrolic-N, exist on the surface, which greatly improves the lithium sulfide adsorption ability and electrical conductivity. As a result, a capacity of 700 mAh g−1 is exhibited for 500 cycles at 0.2 C and 650 mAh g−1 is secured at 5C. Even with a very high active material loading amount of 6.11 mg cm−2, it maintained an areal capacity of 3.1 mAh cm−2 for 500 cycles at 0.2 C with the original free-standing form maintained.