A supercapacitor electrode with ultrahigh areal capacity by using loofah-inspired bimetallic selenide-incorporated hierarchical nanowires

Nanostructure engineering on the electrodes remains challenging for high-performance supercapacitors to meet the ever-increasing demands. Inspired by the function and structure of the loofah which possesses an inner firm skeleton coupled with the outer crisscrossed fibers, herein, a novel loofah-like core-shell na-nostructure is synthesized with well-designed Co0.6Mn0.4Se nanowires dominated as the core, and MnO2 nanoflakes decorated as the shell. The bimetallic selenide exhibits high conductivity and rich electro-chemical activity owing to the coexisting metals component. It also serves as a robust support to hinder the agglomeration of MnO2 nanoflakes, forming a unique porous structure with great ability of self-adapting to volumetric changes. The optimized Co0.6Mn0.4Se/MnO2 electrode exhibits an ultrahigh areal capacity (3.91 F cm-2/0.60 mAh cm-2 at 2 mA cm-2) and an exceptional retention of 95.47 % after 8000 cycles. Both performances are superior to the MnCo2O4/MnO2 electrode without the loofah-like networks in our work. Moreover, the assembled Co0.6Mn0.4Se/MnO2//AC (active carbon) hybrid supercapacitor delivers a high energy density of-89.67 Wh kg-1 at a power density of 399.98 W kg-1, and a remarkable life span with-97.30 % retention after 12,000 charge/discharge cycles. The eye-catching results indicate that the in-tegrated Co0.6Mn0.4Se nanowires show great potential to engineering advanced electrodes. Further de-monstration of the all-solid-state flexible cell based on the bio-inspired Co0.6Mn0.4Se/MnO2 structure also proves its practical application in wearable electronics. (c) 2023 Elsevier B.V. All rights reserved.