reactive coating of metallic and selenophilic AgSe on Se/C cathode materials for high performance Li-Se batteries.

A facile methodology to fabricate a metallic and selenophilic AgSe coating on a Se/nitrogen-doped mesoporous carbon composite, has been successfully developed based on the redox reaction between Se and AgNO under ambient conditions. The reactive growth of AgSe on Se ensures the complete encapsulation of Se by the AgSe coating, which endows the AgSe coating with the dual effects of physical entrapment and chemical binding to effectively confine polyselenide intermediates within the cathodes. With the further assistance of mesopore confinement of the nitrogen-doped carbons, the AgSe-coated Se/nitrogen-doped mesoporous carbon composites present much improved electrochemical performances with a high initial discharge capacity of 652 mA h g, a high coulombic efficiency of 95.4% and a high reversible capacity of 382 mA h g after 100 cycles. These encouraging results suggest that the reactive construction of metallic and chalcogenophilic coating layers on the chalcogen ( S, Se and Te)-based electrode materials should be a promising and easy to scale-up method for practical applications of lithium batteries in light of the very simple reaction processes involved.