A reduced graphene oxide/nitrogen, phosphorus doped porous carbon hybrid framework as sulfur host for high performance lithium-sulfur batteries

Abstract Lithium-sulfur (Li-S) batteries have attracted ever-increasing attentions because of intrinsically high theoretical energy density. However, the insulating property of sulfur and severe polysulfides shuttle effect tremendously hinder their practical applications. Herein, a N, P dual-doped 3D hierarchical porous hybrid carbon is successfully prepared for advanced Li-S batteries based on the combination of reduced graphene oxide (rGO) and goat hair derived biomass carbon (rGO/GPC) by a simple one-pot pyrolysis process. A proper amount of rGO (3%) decorated biomass carbon (rGO/GPC-2) possesses a N, P dual-doped 3D robust porous framework and good electrical conductivity, which can effectively improve the sulfur utilization and immobilize the polysulfides through both physical restriction and chemical adsorption. The as-fabricated rGO/GPC-2-S composite used as Li-S batteries cathode delivers a high initial capacity of 1420 mAh g−1 at 0.1 C and maintains a reversible capacity of 503mAh g−1 after 500 cycles at 1.0 C with an ultralow capacity decay of 0.070% per cycle and excellent rate performance with 500 mAh g−1 at 2.0 C. The enhanced electrochemical performance is attributed to the positive synergistic effect of N, P-dual doped polar porous structure and nonpolar highly conductive hybrid carbon matrix.