Sulfides are the second most abundant compounds after oxides, hosting metals essential for energy application and storage such as copper, lead or zinc. The extraction of those commodity metals provides access to energy critical elements such as silver, molybdenum, rhenium or indium, as by-products. There is however an interest in reconsidering metal extraction methods from sulfides. In particular, methods that prevent SO₂ emissions during processing or that can integrate with the power grid are of appeal. In addition, new extraction techniques with the potential to selectively recover one critical elements independently of the existing smelters are needed to reshape the existing supply chain and allow more recycling. Sulfides are known to electrochemists for their use in sodium polysulfide-based batteries, but little is discussed about their unique properties in the molten state. The presentation reports recent results obtained for both semiconducting and partially ionic melts. The semi-conductor properties prove valuable for high temperature thermoelectricity while the ionic nature of certain sulfides enables to conduct metal extraction by electrolysis. The results prove that a path toward high-temperature electricity harvest or usage thanks to molten sulfides is possible. They also reveal the need for dedicated experimental and modeling efforts to accelerate the rate of generation of thermodynamic and physical chemical data for molten sulfides.