Metal-organic framework derived CoOOH with hierarchical leaf/particle structure grown on carbon cloth as flexible electrode for high-performance supercapacitor

The advancement of high-performance flexible supercapacitors has been fundamentally limited by the insufficient specific capacitance, inadequate cycling durability and low flexibility of traditional electrode materials. To address these issues, electrochemically converted CoOOH with high redox activity and hierarchical leaf/particle structure grown on carbon cloth (CC/CoOOH-LP) was fabricated through composition evolution of ZIF-67 precursors. By systematically deconvoluting the structure and critical phase-transition pathways governing electrochemical performance, the optimal pore hierarchy and phases was realized for CC/CoOOH-LP electrode, which exhibits high areal capacitance of 1515.1 mF cm −2 at 1 mA cm −2 with superior rate capability (retaining 940.1 mF cm −2 at 50 mA cm −2 ). The flexible asymmetric supercapacitor assembled from CC/CoOOH-LP and graphitic carbon nitride electrodes could achieve a high specific capacitance of 207.5 mF cm −2 at 5 mA cm −2 , stable performance upon mechanical bending and charge-discharge cycling (90.99 % capacitance retention over 5000 cycles). This work presents a rationally designed strategy for the preparation of electrochemically converted CC/CoOOH-LP electrode, which features a hierarchically porous structure, high flexibility and superior capacitive performance for flexible energy storage devices.