Hierarchical porous n,O Co-doped carbon/Se composite derived from hydrothermal treated chitosan as li–Se battery cathode

Abstract

Seeking for the porous carbon with suitable structure and morphology has been a key to improve the lithium storage performance of carbon/selenium composite. In this work, the hierarchical porous N,O Co-doped carbon has been prepared by an initial hydrothermal carbonisation and subsequent activation route using the chitosan as raw material. The carbon obtained at 600°C possessing primary micropores and surface macropores presents high specific surface area (809. 3 m2 g−1) and low porous size, and the selenium with amorphous structure is uniformly encapsulated into the micropores of this carbon to form carbon/selenium composite. As the cathode materials of lithium ion battery, this composite delivers a discharge capacity of 446.9 mAh g−1 at rate of 0.24 C after 100 cycles. At a high rate of 4.8 C, this composite still shows a stable discharge capacity of 342.8 mAh g−1. These results suggest that this composite May be promising for practical applications for lithium-selenium battery.