Tailoring rGO-NiFe2O4 hybrids to tune transport of electrons and ions for supercapacitor electrodes

• Published in: Journal of alloys and compounds Vol. 811; p. 152011
• Main Authors: Cai, Yong-Zhu, Cao, Wen-Qiang, Zhang, Yan-Lan, He, Peng, Shu, Jin-Cheng, Cao, Mao-Sheng
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 30-11-2019; Elsevier BV
• Subjects: Capacitance; Commercialization; Electrochemical analysis; Electrode materials; Electrodes; Electrodes material; Electron transport; Graphene; Nanoparticles; Nickel ferrites; NiFe2O4 nanocrystal; Reduced graphene oxide; Spinel; Substrates; Supercapacitor; Supercapacitors; Tailoring; Transition metal oxides; Transition metals; Supercapacitor; Electrodes material; Reduced graphene oxide; Tailoring; NiFe2O4 nanocrystal
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2019.152011

Spinel transition metal oxide is a promising pseudocapacitive materials but the instability gives it narrow practical application. It is shown herein, that an effective remedy for these problems can be achieved by introducing highly conductive two dimensional (2D) reduced graphene oxide (rGO) substrate on which NiFe2O4 nanoparticles are well distributed. The rGO-NiFe2O4 hybrids with different NiFe2O4 contents were tailored to explore the source of the improvement in capacitance performance. It is found that rGO nanosheets in the hybrid can be used as a conductive substrate to accelerate the electron transport. Moreover, NiFe2O4 nanoparticles with a certain volume can simultaneously prevent the restacking of rGO and increase the pseudocapacitance. The G-N3 (30 wt% NiFe2O4) hybrid holds enhanced specific capacitance up to 210.9 F g−1 at 0.5 A g−1 far above that of pristine NiFe2O4 (50 F g−1), and exhibits superior cycle stability with no obvious capacity loss even after 5000 cycles. This research indicates that a tailoring method can promote the electrochemical performance of NiFe2O4, and hopefully accelerate the commercialization of spinel transition metal oxides as electrode materials for supercapacitor.
•Precisely regulated structures of rGO-NiFe2O4 nanohybrids are successfully achieved.•Island-like distributed NiFe2O4 can avoid stacking of rGO and aggregation of NiFe2O4.•Good electron conductivity and facile ion diffusion were achieved simultaneously.•The gravimetric capacity of hybrids electrode is four times that of pure NiFe2O4.