Hollow cotton carbon based NiCo2S4/NiMoO4 hybrid arrays for high performance supercapacitor

• Published in: Journal of energy storage Vol. 59; p. 106553
• Main Authors: Ren, Bo, Zhang, Xin, An, Hongze, Ding, Shuang, Zhang, Hong, Zeng, Xu, Wang, Xiao'e, Fan, Meiqing, Yang, Xiaodong
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.03.2023
• Subjects: Asymmetric supercapacitors; Cotton carbon; Hollow; NiCo2S4/NiMoO4 arrays; NiCo2S4/NiMoO4 arrays; Cotton carbon; Hollow; Asymmetric supercapacitors
• ISSN: 2352-152X; 2352-1538
• DOI: 10.1016/j.est.2022.106553

The design and preparation of new electrode materials with high conductivity and high energy density has become a frontier and key issue in the research of improving the performance of supercapacitor (SCs). Through the synergistic action of biomass carbon and transition bimetallic sulfide, the defects of pseudocapacitor electrode materials such as low conductivity and low energy density can be solved. On hollow cotton carbon (CC), a novel hybrid NiCo2S4/NiMoO4 arrays developed using a simple two-step hydrothermal procedure is reported. A series of characterization methods were used to characterize the samples. Experimental results demonstrated that the CC was hollow and the NiCo2S4/NiMoO4 arrays had uniformly grown on its surface. The sample demonstrated a high specific capacitance (2323 F·g−1 at a current density of 5 mA·cm−2) and outstanding electrochemical stability (90 % retention after 10,000 cycles), according to the electrochemical characteristics. Additionally, a hybrid asymmetric supercapacitor was assembled using CC/NiCo2S4/NiMoO4 (CNCNM) as the positive electrode, CC as the negative electrode, PVA/KOH as the separator and Nickel foam as current collector. The supercapacitor displayed a high energy density (86.52 Wh·kg−1 at 1006.65 W·kg−1), high specific capacitance (341.5 F·g−1 at 5 mA.cm−2), excellent cycling performance (85 % retention after 10,000 cycles), and a low charge transfer resistance. The energy storage capability was studied and a blue LED light (1.8 V) could be lit for 30 min by two similar devices connected in parallel. Cotton carbon (CC) has a highly hollow structure, which can provide large specific surface area, shorten the ion transport path, facilitate rapid charge transmission and enhance the material conductivity. In this paper, core-shell NiCo2S4@NiMoO4 arrays supported on the surface of cotton carbon (CNCNM) were prepared. A hybrid asymmetric supercapacitor was fabricated using CC/NiCo2S4/NiMoO4 (CNCNM) as the positive electrode, CC as the negative electrode, and PVA/KOH as the separator. The supercapacitor displayed a high energy density (86.52 Wh·kg−1 at a power density of 1006.65 W·kg−1), high specific capacitance (341.5 F·g−1 at a current density of 5 mA.cm−2), low charge transfer resistance, excellent cycling performance (85 % retention after 10,000 cycles), and a low charge transfer resistance. [Display omitted] •NiMoO4 nanosheets decorated on NiCo2S4 nanorods.•The hybrid arrays stand on hollow cotton carbon surface.•The CNCNM electrode has good electrochemical properties.•A supercapacitor was fabricated using CNCNM as cathode and CC as anode.•The device has a high energy density and good stability.