Cu-MOFs derived three-dimensional Cu1.81S@C for high energy storage performance

Significant volume changes and slow ionic transport during charge/discharge processes restrict the improvement of electrochemical performance for CuxS (x = 1-2). Herein, a new strategy by introducing Cu-BTC (copper(II)benzene-1,3,5-tricarboxylate) as a processor to derive three-dimensional Cu1.81S@C using green sulfurization and calcination methods is proposed. Benefiting from the high electrical conductivity, multistage pore size structure and stable structure brought by the conductive carbon skeleton after calcination, Cu1.81S@C-650oC exhibits a high specific capacitance of 291.1 F g-1 at a current density of 1 A g-1 and a superior rate capability of 83.6 % at a current density of 10 A g-1. In addition, the assembled asymmetric supercapacitor (Cu1.81S@C-650oC//AC ASC) also shows impressive performances, such as an energy density up to 16 Wh kg-1 at a power density of 352 W kg-1 and an excellent cycling stability of 93.1 % over 5000 cycles at a current density of 2 A g-1. This work demonstrates that the Cu-BTC-derived Cu1.81S@C is an attractive material with potential applications in energy storage devices.