Designing an asymmetric device based on 3D hierarchical tri-metal Co-Mn-Fe selenide/NF porous nano-flowers electrode for efficient energy storage

Abstract

The construction of high-performance supercapacitors (SC) requires the development of an electrode material with a highly porous structure. Further, rational engineering and designing electrodes with multi-component and promising architectures can substantially enhance their electrochemical performance. Transition metal dichalcogenides have recently received considerable attention due to their unique electronic structure and superior electrical conductivity, emerging as an application in conversion and energy storage devices. Herein, we present a novel hierarchical synthesis for a 3D hierarchical tri-metal Co-Mn-Fe selenide/NF (CMFSe/NF) nano-flowers with porous petals, in which the 3D tri-metal Co-Mn-Fe LDH/NF (CMF LDH/NF) nanoflowers uniformly grow on the whole surface of nickel foam (NF). A one-step ion-exchange selenidization process was used to convert the hierarchical Co-Mn-Fe LDH/NF to Co-Mn-Fe selenide/NF, which exhibits superior structural integrity. Simultaneously, the surface of the uniform nano-flowers becomes velvety and significantly porous, promoting the specific surface area and robustness structure and providing a fast electron pathway. Thanks to their three-dimensional interconnected architecture and nanoporous nature, the CMFSe/NF electrode shows an exceptional capacity of 671.2 C g−1 and outstanding rate performance, demonstrated by a 76.1 % capacity retention at 48 A g−1. The CMFSe/NF hybrid supercapacitor was constructed using activated carbon (AC) as the anode and the CMFSe/NF as the cathode in a solution of 6 M KOH. The constructed asymmetric supercapacitor device of CMFSe/NF (+)||AC(-) achieved a high capacity of 265.1 C g−1 at 1 A g−1, a prominent rate capability of ∼68.5 % at 48 A g−1, a high specific energy of 62.8 Wh kg−1, and a specific power up to 40,735.1 W kg−1.