Growing hierarchical CoNi-based phosphates sandwiched Ni metal on carbon cloth for advanced supercapacitors

Abstract

The rational design of electrode materials plays an important role in the development of supercapacitors. Although CoNi-based phosphate as active material for supercapacitor shows great potential including high theoretical capacitance, low cost, and environmental friendliness, the further investigation of CoNi-based phosphate with structural design to achieve high performance is of great urgent. In this work, hierarchical CoNi-based phosphates sandwiched Ni are directly grown on carbon cloth (CC@CoNi-PO/Ni/CoNi-PO) as freestanding electrode for supercapacitors. The introduction of Ni into hierarchical CoNi-based phosphates with abundant redox active sites can improve the integral electrochemical performance. In three-electrode system, the CC@CoNi-PO/Ni/CoNi-PO sustains a cycling stability of 94.7% after 1000 cycle (20 mV s−1), which is better than those of CC@CoNi-PO (85.9%) and CC@CoNi-PO/CoNi-PO (91.8 %). Matched with activated carbon as negative electrode, the hybrid supercapacitor delivers considerable stability of 88.3% capacitance retention after 2000 cycles at 100 mA cm−2.

Keywords

• CoNi-based phosphates
• Supercapacitors
• Electrochemical performance
• Hierarchical structure
• Cycling stability