摘要
The use of poly(4-styrene sulfonic acid) (PSSA) to effectively disperse graphene in an aqueous sulfur (S) cathode slurry is proposed, and the cell performance of the resulting Li−S battery is investigated and compared to that of the battery prepared by adding as-received graphene. The addition of PSSA improves not only the dispersion of the as-received graphene, but also the homogeneity of the constituents in the S cathode slurry; accordingly, better electronic and ionic conductivities are obtained. The electrical impedance of the cell constructed using the S cathode with the as-received graphene is greatly reduced from 142.0 to 14.6 Ω when PSSA is added during the preparation of the cathode. Moreover, the addition of the PSSA-dispersed graphene to the S cathode significantly improves the capacity, cycle life, and coulombic efficiency during the charge-discharge process, since PSSA increases the contact between the dispersed graphene and the insulated S powder.