Construction and electrochemical properties of carbon nanotube composite Mn-MOFs materials electrode for high-performance flexible supercapacitors

Abstract

Metal organic frameworks (MOFs) as electrode materials for supercapacitors have attracted extensive attention due to their porous structure. However, the poor conductivity of MOFs limits the charge transfer. In this work, Mn-MOF/carbon nanotube (CNT) composites were grown directly on carbon cloth (CC) in one step by the traditional hydrothermal synthesis of MOFs to improve the electrical conductivity of Mn-MOFs. The structural and performance tests show that CNTs, as a conductive backbone, can connect Mn-MOFs to each other, which can obviously solve the problem of poor conductivity of MOF materials. The Mn-MOFs/CNTs/CC electrodes show a larger specific capacitance and excellent cycling stability by electrochemical tests. Compared to the original Mn-MOF electrode, the surface capacitance obtained increases from 188.8 mF·cm−2 to 385.8 mF·cm−2 at a current density of 0.8 mA·cm−2 and maintains a high capacitance retention of 118% after 5000 charge/discharge cycles at a current density of 5 mA·cm−2. This work confirms that the in- situ synthesis of MOFs and CNTs has promising applications in fabric-based flexible supercapacitors.