Hierarchical porous carbon/selenium composites derived from abandoned paper cup as Li-Se battery cathodes.

Abstract Paper cup composed of crude cellulose is a common waste in daily life. In this paper, hierarchical porous carbons have been successfully prepared by an initial hydrothermal treatment and subsequent activation route from abandoned paper cup, and then paper cup derived carbons are used as scaffolds to fabricate serial carbon/Se composites. The optimal composite presents unique 3D porous structure, with amorphous selenium uniformly confined into the micropores of carbon. As the cathode materials of Li-Se battery, this composite reveals an initial reversible discharge capacity of 517.2 mAh g−1 at 0.2C, and a capacity value of 431.9 mAh g−1 can be retained after 60 cycles. Even at a high rate of 4C, a capacity value of 295.8 mAh g−1 can be obtained. By comparison, the improved electrochemical performance of the optimal composite should be attributed to reasonable porous structure and effective encapsulation of amorphous selenium. Graphical abstract Image 1 Highlights • Synthesis of porous carbon/Se composite from abandoned paper cup. • Porous carbon/Se composite delivers a stable discharge capacity of 295.8 mAh/g at 4C. • The structure-function of different carbon/Se composites is studied. [ABSTRACT FROM AUTHOR]