N, S co-doped lignin graded porous carbon as efficient Pt-free counter electrodes for dye-sensitized solar cells

Pt counter electrodes are essential components of dye-sensitized solar cells (DSSCs). However, their high cost and poor stability limit the development of these cells. In the quest for alternative materials to replace Pt, this study utilized sodium lignosulfonate as the primary raw material and successfully prepared N, S co-doped hierarchical porous carbon by adjusting the ratio of thiourea. This carbon was then fabricated into a counter electrode to replace Pt. The results showed that the N, S co-doped hierarchical porous carbon exhibited superior electrochemical performance compared to single-atom doped carbon. When used as the counter electrode in DSSCs, it achieved a power conversion efficiency of 8.62%, which is higher than the 7.98% efficiency of Pt. Furthermore, it demonstrated greater stability than Pt in stability tests. These findings confirm that N, S co-doped hierarchical porous carbon could replace Pt, thereby advancing the scientific understanding of DSSCs and promoting their application and development.