Two-for-one strategy: Three-dimensional porous Fe-doped CoO cathode and N-doped carbon anode derived from a single bimetallic metal-organic framework for enhanced hybrid supercapacitor.

"Two-for-one" strategy is an effective method to construct two kinds of materials from a single precursor owing to the simplicity of fabricating procedure and reduction of manufacturing cost. However, such a strategy has seldom been utilized to produce both battery-type and capacitive electrodes of a hybrid supercapacitor (HSC) device. Here, we adopt the "two-for-one" strategy to fabricate three-dimensional (3D) porous iron-doped (Fe-doped) CoO and nitrogen-doped (N-doped) carbon via a single bimetallic metal-organic framework, FeCo-ZIF-67. Fe-doped amounts and carbonization temperature are used to adjust their individual electrochemical behaviors. The optimal 3D porous Fe-doped CoO and N-doped carbon possess a high capacitance of 767.9 and 277C g at 1 A g, respectively. Charge storage mechanism of Fe-doped CoO is further investigated via analysis of capacitive and diffusion-controlled contribution. A Fe-doped CoO//N-doped carbon HSC device achieves desirable specific energy (37 Wh kg) and power (750 Wkg), and satisfied cycling stability (90% retention after 4000 cycles). A light-emitting diode (LED) is successfully light by the HSC device, suggesting its potential application in the field of green energy conversion and storage devices.