Ternary Composite Nanosheets with MoS₂/WS₂/Graphene Heterostructures as High‐Performance Cathode Materials for Supercapacitors

Abstract

A new class of ternary heterostructures consisting of a reduced graphene oxide, molybdenum disulfide, and tungsten disulfide (rGO‐MoS2‐WS2) is prepared through a simple chemical method. According to Raman and X‐ray photoelectron spectroscopy, a MoS2/WS2 heterostructure is uniformly formed on the conductive rGO support. Furthermore, rGO‐MoS2‐WS2 possesses s large surface area of 109 m2 g−1 and a hierarchical pore architecture. When serving as the electrode for supercapacitors, rGO‐MoS2‐WS2 exhibits pseudocapacitive behavior in a KOH solution. It is found that rGO‐MoS2‐WS2 displays a specific capacitance (Cs) of 365 F g−1 at 1 A g−1, which is much higher than those of single TMD (MoS2 or WS2)‐based composites. The enhanced electrochemical performance of rGO‐MoS2‐WS2 is attributed to the lower internal resistance through heterostructure formation, the wide range of TMD oxidation states, and uniform distribution of the few‐layered TMD nanosheets on the rGO surface. Furthermore, the optimal loading amount of MoS2/WS2 heterostructure in the composite is investigated. To demonstrate its practical application, rGO‐MoS2‐WS2 is used as a positive electrode for an asymmetric supercapacitor (ASC). The maximum energy density of the ASC device is 15 Wh kg−1 at a power density of 373 W kg−1. Furthermore, the device remains approximately 70 % of the initial Cs value after 3000 cycles, which shows the excellent cycling stability.

Porous and Hierarchically Structured Ammonium Nickel Molybdate/Nickel Sulfide/Reduced Graphene Oxide Ternary Composite as High Performance Electrode for Supercapacitors

“…The Ragone plot of the device (Figure d) exhibits a maximum energy density of 24.2 Wh kg −1 at the power density of 1.75 kW kg −1 and retains 14.9 Wh kg −1 at the high power density of 4 kW kg −1 . The energy densities of ANM‐NiS‐rGO//rGO are comparable to those of ternary composite based HSCs including rGO‐MoS 2 ‐WS 2 //rGO (15 Wh kg −1 at 373 W kg −1 ), NiCo 2 S 4 @rGO//AC (21.9 Wh kg −1 at 417 W kg −1 ), NiCo 2 S 4 @NiO//AC (10.36 Wh kg −1 at 720 W kg −1 ), CoMoS 4 //rGO (27.2 Wh kg −1 at 400 W kg −1 ), NiCo 2 O 4 @NiMoO 4 //AC (21.7 W h kg −1 at 157 W kg −1 ), NiCo 2 S 4 @NiMoO 4 /NF//AC (21.4 Wh kg −1 at 58 W kg −1 ) . Another important key factor of the HSC device is its self‐discharge characteristics.…”

“…Firstly, the formation of thin ANM nanosheets improves the electrode performance because it is well known that morphological effect plays a critical role in electrochemical properties . Secondly, the high conductivity of graphene sheets facilitates electron transport in the ternary composite and the electrons can be easily delivered to active materials . Thirdly, highly active NiS nanoparticles provide the additional capacitive contribution for SCs .…”

Layered molybdenum disulfide coated carbon hollow spheres synthesized through supramolecular self‐assembly applied to supercapacitors

“…According to the Equation 4 and Equation 5 in supporting information, the flexible supercapacitor exhibits an energy density of 34.0 Wh kg −1 at a power density of 611.6 W kg −1 . As shown in Figure 6H, even at 5556.2 W kg −1 , it still remains 15.4 Wh kg −1 , which is better than most TMD and Mo‐based asymmetric supercapacitors (Table S2), such as rGO//MoS 2 @HCS (13.7 Wh kg −1 ), 57 AEG//MoS 2 /GF (16 Wh kg −1 ), 58 rGO//rGO‐MoS 2 ‐WS2‐4 (15 Wh kg −1 ), 59 and C//NiCo 2 S 4 (22.8 Wh kg −1 ) 60 . The comparison of the electrochemical parameters of asymmetric supercapacitor can be found in Table S2 in Supplementary Material.…”

A 3D Carbon Foam Derived from Phenol Resin via CsCl Soft‐Templating Approach for High‐Performance Supercapacitor

“…Even after 10 000 cycles, its specific capacitance does not change or change very little. However, its specific capacitance and energy density are smaller than Faraday capacitor, which limits its further application …”