Encapsulation of SeS₂ into Nitrogen-Doped Free-Standing Carbon Nanofiber Film Enabling Long Cycle Life and High Energy Density K-SeS₂ Battery

K-SeS2 batteries could provide a low-cost and high energy density energy storage system, because the earth-abundant element potassium (K) shows a low reduction potential and a high gravimetric capacity. But the K-SeS2 battery has never been reported because of the lack of high-performance electrode materials. Herein, we design an advanced K-SeS2 battery by encapsulation of SeS2 in the nitrogen-doped free-standing porous carbon matrix...