Multifunctional-regions integrated with Mn-Co-Ni ternary hydroxides as self-assembled electrodes for high-performance hybrid supercapacitors

Abstract

High-performance supercapacitors require elaborate design for electroactive materials with hierarchical structure and multiple components. In the present work, hierarchical nanoarrays composed of MnCoNi LDH@CoNi LDH (MCNL@CNL) with enoki-mushroom-like structure were constructed by integrating the structural regions with complementary functions. The self-assembled electrodes were fabricated upon MCNL@CNL with MnCo LDH@ZIF-67 as precursor and nickel foam as supporter, which achieved a specific capacitance of 2126.7 F/g at 0.5 A/g. The assembled hybrid supercapacitor exhibited the maximum energy density and power density of 51.4 Wh/kg and 7500 W/kg within the voltage range of 0–1.5 V, respectively, and it provided cycling stability with high capacitance retention (104.1%) and Coulombic efficiency (101.1%) after 10,000 cycles. Based on the characterizations results, MCNL@CNL electrode endowed with fast mass transfer, high conductivity and rich electroactive sites was produced, and its induced synergy effect facilitated charge transfer and promoted specific capacitance. Moreover, the hierarchical structure and rough surface of the fabricated MCNL@CNL accelerated the ions/electrons diffusion, and the cross-growing nanosheets on the surface enhanced the affinity. This work provides a novel approach to designing and fabricating self-assembled electrodes with high-performance and lifetime for supercapacitors.