A high-performance electrode based on low cobalt content Co0.12Ni1.88S2 growing on honeycomb-like NiCo(HPO4)2·3H2O for hybrid supercapacitors

Abstract

It is desirable to design highly electrochemically active materials for practical hybrid capacitors to fulfill the demand of rapid development of portable and wearable electronics. In this work, ternary Co0.12Ni1.88S2 with low cobalt content is electrodeposited on honeycomb-like NiCo(HPO4)2·3H2O modified carbon cloth (CC@Ni–Co–P@Co0.12Ni1.88S2). The as-prepared CC@Ni–Co–P@Co0.12Ni1.88S2 can avoid the introduction of inactive components. Besides, the honeycomb-like Ni–Co–P modifier provides many active sites for Co0.12Ni1.88S2 deposition and improves its utilization efficiency. Significantly, in the three-electrode system, the CC@Ni–Co–P@Co0.12Ni1.88S2 shows specific capacitance of 1.06 F/cm2, which is three times higher than that of CC@Co0.12Ni1.88S2 without Ni–Co–P modification. Surprisingly, the hybrid supercapacitors based on CC@Ni–Co–P@Co0.12Ni1.88S2 cathode and active carbon anode also delivers excellent long-term cycle stability with capacitance retention of 94.8% after 10,000 cycles. This rational structure design provides a choice for achieving high utilization of high-quality active materials.