Se–C Bond in SnSe2–Porous Biomass Carbon Boosting Fast and Durable Potassium Storage

Potassium-ion batteries (PIBs) have gained considerable attention as a result of the affordable price and abundant availability of potassium. However, a highly stable anode material to reversibly store K+ ions during the charge and discharge process still needs to be developed for the commercialization of PIBs. In this work, different ratios of the Sn precursor and biomass-derived porous carbon (PC) were used for the "direct coordination reaction on PC", followed by carbonization and selenization to fabricate four different SnSe2@C@PC-x (where x = 1, 2, 3, and 4) materials. Among them, SnSe2@C@PC-3 consisting of large interlayer spacing SnSe2 presented a three-dimensional (3D) porous structure with a high surface area and inherent Se-C bond formation between SnSe2@C and PC and provided abundant active sites and fast transfer channels for electrons/K+, leading to high capacity and excellent reaction kinetics. Thus, SnSe2@C@PC-3 displayed strongly improved long cycling performance, especially at a high current density, compared to that of SnSe2@C@PC-1, SnSe2@C@PC-2, SnSe2@C@PC-4, and pristine SnSe2@C. This work provides new insight into enhancing the cycling stability of metal selenides as anode materials for PIBs