Tuning MnO2 to FeOOH replicas with bio-template 3D morphology as electrodes for high performance asymmetric supercapacitors

By Xiaoying Liu, Tianxu Zheng, D. Jiang, Zheng Zhou, C. Liu, Xianming Zhang, Yuxin Zhang, Dusan Losic. Chemical Engineering Journal, 2019

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Abstract Controlled synthesis of tunable Mn-iron-oxide (Mn-FeOx) hybrids with unique three-dimensional (3D) porous structure based on diatoms for high performance supercapacitors is demonstrated. Successful transition process from MnO2 to FeOOH on diatomite was performed by two-step hydrothermal method and resultant replicas with 3D diatom morphology were obtained via etching process. The fabricated MnFeOx-0 diatom replica without transition was composed by MnO2 nanosheets and exhibited a high specific capacitance (228.6 F g−1 at 1 A g−1), good rate capability (74.6% retention after current density were increased to 10 A g−1), high coulombic efficiency (about 93.1% at 10 A g−1), and steady cycling performance (94.3% capacitance retention after 4000 cycles). MnFeOx-110 replica with FeOOH nanorods owned 224.6 F g−1 at 1 A g−1, high coulombic efficiency about 80% at 10 A g−1 and steady cycling performance about 92.5% retention after 4000 cycles. Finally, an asymmetric supercapacitor was assembled based on MnO2 nanosheets as the positive electrode and FeOOH nanorods as the negative electrode, which delivered a wide potential of 2 V with maximum energy density of 51.5 Wh kg−1 and power density of 9.1 kW kg−1. Considering that the two replicas owned great energy storage property, it opens an opportunity for rational design of the diatom morphology samples applied to high-performance supercapacitors.

Subfields: Electronic, Optical and Magnetic Materials, Environmental Engineering, Renewable Energy, Sustainability and the Environment

View Paper: https://www.semanticscholar.org/paper/40d11d2ff51d03647c6be33ec4b44d161be459a3