ZIF-67 derived NiCoP nanosheets on carbon cloth as a flexible cathode for high-performance solid-state asymmetric supercapacitors

Herein, unique bimetallic phosphide of NiCoP with nanosheet structure coated on carbon cloth (NiCoP@CC) was synthesized. Three-dimensional cobalt-based ZIF-67 (Co-ZIF-67) with dodecahedron morphology was first grown on carbon cloth, and then the NiCoP nanosheets were formed through a synthesis procedure involving Ni2+- induced template scarification of the Co-ZIF-67 and the phosphorization calcination. Impressively, the resulting NiCoP@CC electrode shows a remarkable specific capacity of 1149.2 C g-1 (6.09 C cm-2) at 1 A g-1 and superior cycle performance (the capacity retains 99.7 % after cycled for 10,000 cycles at 6 A g-1), owing to the optimized ZIF-67-template modification, unique morphology, good electronic conductivity, superiority of the bimetallic phosphides, and the battery type feature. Further, a solid-state asymmetric supercapacitor (ASC) was fabricated by using the obtained NiCoP@CC as the cathode and using active carbon (AC) as the anode. The assembled ASC device delivers a high specific energy of 78.5 Wh kg-1 at the specific power of 799.5 W kg-1, and remains 90.3 % capacity retention over 10,000 cycles at 8 A g-1, demonstrating its high potential for applications in the field of high-capacity supercapacitors. These results illustrate the promise of NiCoP@CC as a promising cathode material in supercapacitor.

Automated summary

In this study, a unique NiCoP nanosheet structure was successfully synthesized and coated on carbon cloth, exhibiting excellent capacitance performance and cycle stability. A solid-state asymmetric supercapacitor (ASC) was fabricated using the NiCoP@CC as the cathode and active carbon as the anode, demonstrating high specific energy and long cycle life, indicating its potential in high-capacity supercapacitor applications.