Dynamic Cross‐Linking of Organosulfur and Organoselenium in a Biphasic Cathode for Balanced High‐Performance Lithium Batteries

ABSTRACT Sulfur and organosulfur compounds have emerged as promising cathode materials for high‐energy lithium batteries owing to their high theoretical capacity, element abundance, and structural tunability. However, either sulfur or organosulfur cathodes are difficult to achieve high capacity, cyclic stability, and redox kinetics at the same time due to the inherent trade‐off. Herein, a solid–liquid biphasic organochalcogen cathode is reported to overcome this performance trade‐off for next‐generation lithium batteries. The in situ cross‐linking between an organosulfur polymer and a small‐molecule organoselenium compound significantly enhances the charge transfer and ionic diffusion kinetics of the cathode. Furthermore, the small‐molecule organoselenium and intermediate products could be immobilized within the cathode by the polar functional groups within organosulfur, resulting in cycling performance that is markedly superior to that of cathodes using inorganic elemental sulfur paired with organoselenium. Benefiting from this complementary effect, the optimized cathode exhibited ultra‐long cycle stability with capacity decay of 0.017% per cycle within 2,700 cycles at 2 mA g −1 and achieved a high areal capacity of 11.36 mAh cm −2 . This biphasic organochalcogen cathode strategy provides a rational design paradigm for lithium‐organic batteries with excellent comprehensive performance.