One-Dimensional Co-Carbonate HydroxideNi-Mofs Composite with Super Uniform Core-Shell Heterostructure for Ultrahigh Rate Performance Supercapacitor Electrode

The insufficient contact between two phases in heterostructure weakens the coupling interaction effect, which makes it difficult to improve the electrochemical performance effectively. Herein, a novel Co-carbonate hydroxide@Ni-MOFs (Co-CH@Ni-MOFs) composite with super uniform core-shell heterostructure has been fabricated by adopting one-dimensional (1D) Co-CH nanowires as structure-directing agents and substrates 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 for 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 electrochemical characteristics of each component. On the other hand, the fabrication of 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 capacitance of 1246 F g −1 at 1 A g −1 , and an ultrahigh rate capability of 70.3% at 150 A g −1 as well as excellent cycling stability with 90.1% capacitance retention after 10000 cycles at 10 A g −1 . Furthermore, the asymmetric supercapacitor assembled by the Co-CH@Ni-MOFs and activated carbon exhibits a high energy density of 58.0 W h kg -1 at a power density of 800 W kg -1 and holds 29.9 W h kg -1 at high power density of 16000 W kg -1 . This study may offer a versatile design for fabricating MOFs based heterostructure with sufficiently contacted interfaces as energy storage electrodes