Construction of 3D carbon dots/Prussian blue analogue-derived phosphide nanocomposites on Ni foam for high-performance supercapacitors

Abstract

A desirable electrode material with rational architecture and superior composition is the key to optimize the electrochemical performance of supercapacitor. Prussian blue analogues are a kind of promising precursors for electrode preparation with the features of adjustable compositions and rigid frame structure. In this work, carbon dots/nickel iron phosphide nanoparticles grown on Ni foam have been delicately designed and synthesized from PBAs for the application of cathode of hybrid supercapacitors (HSC). Introduction of CDs is found that not only favors the nanocubes growth of PBAs precursor but also alleviates aggregation of the nanocubes during calcination and phosphorization. The uniform coverage of carbon dots on the phosphides offers hydrophilic interfaces beneficial to the interaction between electrodes and electrolyte and improves the chemical stability of the electrodes. With these assets, the optimum electrode exhibits remarkable areal capacitance (2589 mF cm−2 at a current density of 2 mA cm−2), noteworthy rate performance and excellent cycling stability. Moreover, the as-fabricated hybrid supercapacitor shows a high energy density and power density, as well as high stability. These results indicate that the CDs/NiFeP-NF electrode has the desirable potential to be a candidate for energy storage devices. The structure modulation in this work may provide a new avenue for development of PBAs-based phosphides materials in the field of energy conversion and storage.