One-Dimensional Co-Carbonate Hydroxide@Ni-MOFs Composite with Super Uniform Core-Shell Heterostructure for Ultrahigh Rate Performance Supercapacitor Electrode.

Abstract

The insufficient contact between two phases in the heterostructure weakens the coupling interaction effect, which makes it difficult to effectively improve the electrochemical performance. Herein, a Co-carbonate hydroxide@ Ni-metal organic frameworks (Co-CH@Ni-MOFs) composite with super uniform core-shell heterostructure is fabricated by adopting 1D Co-CH nanowires as structuredirecting agents to induce the coating of Ni-MOFs. Both experimental and theoretical calculation results demonstrate that the heterostructure plays a vital role in the high performance of the as-prepared materials. On the one hand, the construction of super uniform core-shell heterostructure can create a large number of interfacial active sites and take advantages of the electrochemical characteristics of each component. On the other hand, the heterostructure can increase the adsorption energy of OH- ions and promote the electrochemical activity for improving the reversible redox reaction kinetics. Based on the aforementioned advantages, the as-fabricated Co-CH@Ni-MOFs electrode exhibits a high specific capacity of 173.1 mAh g-1 (1246 F g-1 ) at 1 A g-1 , an ultrahigh rate capability of 70.3% at 150 A g-1 and excellent cycling stability with 90.1% capacity retention after 10 000 cycles at 10 A g-1 . This study may offer a versatile design for fabricating a MOFs-based heterostructure as energy storage electrodes.