Self-Assembled Hierarchical Silkworm-Type Bimetallic Sulfide (NiMo₃S₄) Nanostructures Developed on S-g-C₃N₄ Sheets: Promising Electrode Material for Supercapacitors

Abstract

An electrode material composed of bimetallic sulfides on g-C 3 N 4 typically enhances the energy storage capacity of devices due to the merits of each component, but it still suffers from low energy density over long cycles. Although Ni-based bimetallic sulfides have become good electrode materials for supercapacitors, practical applications of these materials are hindered due to unsatisfactory cycling stability. Here, we demonstrate a simple two-step in situ approach to prepare bimetallic sulfide nanobulbs on a sulfur-doped graphitic carbon nitrate matrix for a NiMo 3 S 4 @S-g-C 3 N 4 composite, which is further used for supercapacitor devices. A small amount of sulfur doping to g-C 3 N 4 enhances the conducting channels for electron transportation. An NMS@S-gC nanocomposite clearly shows the formation of small nanobulbs that are formed as silk warm-type hierarchical morphology structures and these were wrapped on the surface of S-gC porous nanosheets. The device made up of these composites exhibited a maximum specific capacitance of 142.4 F g −1 , a high energy density of 41.4 Wh kg −1 , and a power density of 723.5 W kg −1 at a current density of 1 A g −1 . Meanwhile, in a three-electrode device configuration, the working electrode demonstrates a specific capacitance of 934.2 F g −1 at 1 A g −1 , which is 1.6 times greater than that of bare NiMo 3 S 4 . Moreover, the capacitance retention of the device is about 91% even after 5000 cycles at 8 A g −1 . The results obtained in this investigation surpassed most reported metallic sulfides on g-C 3 N 4 . Hence, this work could give a different pathway for the synthesis of electrode materials for energy storage devices.

Ni–Co Nanorods Decorated on MNS Nanoflowers to Form Heterostructures on Ni Foam for Fostering the Performance of Asymmetric Supercapacitors

“…The MNS@NiCo NS sample shows peaks at 23.3, 26.2, 27.8, 33.7, 36.7, 37.8, and 57.9°, which can be indexed to the planes of (111), ( 200), ( 210), (211), and (311) of the MNS phase (JCPDS: 01−088−1802). 34 In addition, the XRD spectra of MNS demonstrate two smaller peaks correlated to the (111) and (200) planes of the NiS 2 phases (PDF#65−3325). 30 Noteworthy, the NMS@NiCo NSs show no distinct peaks, predominantly caused by the weaker crystallization of the as-developed nanorods.…”

“…The XRD patterns of MNS samples show peaks of nickel sulfide and moly sulfide in addition to (MNS) NiMo 3 S 4 , confirming that the possible secondary phase formations and the desired MNS phase formation are successfully produced. The MNS@NiCo NS sample shows peaks at 23.3, 26.2, 27.8, 33.7, 36.7, 37.8, and 57.9°, which can be indexed to the planes of (111), (200), (210), (211), and (311) of the MNS phase (JCPDS: 01–088–1802) . In addition, the XRD spectra of MNS demonstrate two smaller peaks correlated to the (111) and (200) planes of the NiS 2 phases (PDF#65–3325) .…”

Ni0.5Co0.5S nano-chains: a high-performing intercalating pseudocapacitive electrode in asymmetric supercapacitor (ASC) mode for the development of large-scale energy storage devices

“…51,52 Bimetallic sulfides are regarded as a promising class of electrode materials for high-performance energy storage devices due to their exceptional electrochemical activity and capacity compared to most mono-metal sulfides. [53][54][55][56][57][58] Due to their distinctive physical, chemical, electrical, and optical properties, as well as their numerous potential applications in catalysis and electrochemical supercapacitors, Ni-Co-S compounds with different stoichiometric compositions, such as NiCo 2 S 4 , [59][60][61][62] CoNi 2 S 4 , [63][64][65] Ni 1.5 Co 1.5 S 4 , 66,67 Ni x Co 3−x S 4 , 68,69 (Ni 0.5 Co 0.5 ) 9 S 8 , 70 and Ni x Co 1−x S 2 , [71][72][73] have drawn significant attention. Electrochemical activities can be maximized by altering the active material compositions, fine-tuning the electronic struc-tures, and adjusting the active sites of materials.…”

“…51,52 Bimetallic sulfides are regarded as a promising class of electrode materials for high-performance energy storage devices due to their exceptional electrochemical activity and capacity compared to most mono-metal sulfides. [53][54][55][56][57][58] Due to their distinctive physical, chemical, electrical, and optical properties, as well as their numerous potential applications in catalysis and electrochemical supercapacitors, Ni-Co-S compounds with different stoichiometric compositions, such as NiCo 2 S 4 , [59][60][61][62] CoNi 2 S 4 , [63][64][65]…”

High-performance flexible solid-state asymmetric supercapacitor with NiCo2S4 as a cathode and a MXene-reduced graphene oxide sponge as an anode

“…Many transition metal suldes (TMSs) are well-studied as active cathode materials for supercapacitors because of their high electrochemical activity and theoretical specic capacitance. [13][14][15] However, single TMSs have certain limitations, including reduced specic capacity under high current densities and insufficient cycling stability. To effectively address these issues, it is vital to develop mixed metal suldes consisting of a signicantly high number of redox sites, enhanced capacitance, and superior electrical conductivity compared to single transition metal suldes and transition metal oxides.…”