Ultra-high rate capability of synergistically built dual-nanostructure of NiCo2S4/nickel foam as an electrode in supercapacitors
The microstructure of electrode materials and its synergism with current collectors has been a research focus in the area of Faraday supercapacitors (FSs), while the microstructure of current collectors has been neglected in most cases. To eliminate the electrochemical bottleneck of FSs, the comprehensive consideration on electrodes should simultaneously include both the microstructures of materials and current collectors, and their synergism. In this work, a dual-nanostructure of NiCo2S4/nickel foam is built to achieve an electrode with structure-synergistical contribution from materials and current collectors. The as-built electrode presents ultra-high rate capacity (1223.8 C g-1 at 2.5 A g-1; 53.40% capacity retention at ultra-high current density of 148.5 A g-1) and excellent cycling stability (94.56% capacity retention after 10000 charge-discharge cycles). The as-assemble asymmetrical supercapacitors show both high energy and power densities (76.7 Wh kg-1 at 425.7 W kg-1; 41.9 Wh kg-1 at 10643.3 W kg-1). These results demonstrate that the dual-nanostructure of electrode is valuable for achieving high performance supercapacitors.