Enhancing interfacial electron transfer by gradiently constructing polyaniline electron bridge between MOF and MnOx for high performance flexible supercapacitors

Abstract

Tailoring the dynamic construction of hetero-junction has emerged as a promising strategy for accelerating interfacial electron transfer for high performance flexible supercapacitors (FSCs), which remains a huge challenge. Here we engineer the O_v-CoFe-MOF/MnO_x hetero-junction with the gradiently constructed polyaniline (PANI) electron bridge to accelerate the interfacial charge transfer and improve the active site utilization. This configuration promotes the surface dynamic reconstruction by the formation of dual built-in electric field and provides high loading of the outing MnO_x layer by the strong interface adaptability. And, the optimal electronic structure modification of both O_v-CoFe-MOF and MnO_x enhances reaction kinetics. And, the superior O_v-CoFe-MOF@90PANI@MnO_x electrode achieved high area specific capacitance of 1193.18 mF/cm² and maintained high capacitance retention of 92.15% over 30,000 cycles. Importantly, the FSCs assembled with O_v-CoFe-MOF@90PANI@MnO_x electrodes show high energy density of 354 mWh/cm² and keep high capacitance retention of 89.47% after 25,000 cycles, along with high flexibility at varied bending angles. The combination of two FSCs in a series can illuminate the LED arrays, indicating the potential value in practical applications. Furthermore, this study introduces an effective design for regulating electron transfer by constructing the PANI electron bridge, paving the way for the more promising energy storage devices.