Cobalt sulfide aerogel prepared by anion exchange method with enhanced pseudocapacitive and water oxidation performances

This work introduces the anion exchange method into the sol-gel process for the first time to prepare a metal sulfide aerogel. A porous Co9S8 aerogel with a high surface area (274.2 m2 g−1) and large pore volume (0.87 cm3 g−1) has been successfully prepared by exchanging cobalt citrate wet gel in thioacetamide and subsequently drying in supercritical ethanol. Such a Co9S8 aerogel shows enhanced supercapacitive performance and catalytic activity toward oxygen evolution reaction (OER) compared to its oxide aerogel counterpart. High specific capacitance (950 F g−1 at 1 A g−1), good rate capability (74.3% capacitance retention from 1 to 20 A g−1) and low onset overpotential for OER (220 mV) were observed. The results demonstrated here have implications in preparing various sulfide chalcogels.