**6.1 Carbon-MoS2 composite electrode materials**

MoS2/MWCNT nanocomposite synthesized by a hydrothermal method exhibited a large surface area and fast ionic transport properties and showed a high specific capacitance of 452.7 F g−1 with good cycling stability (95.8% retention after 1000 cycles), which is almost three times larger than the bare MoS2 (149.6 to 452.7 F g−1) [71]. Ali *et al.* fabricated MoS2/graphene composite from bulk MoS2 and graphite rod through facile electrochemical exfoliation method and exhibited high specific capacitance of 227 F g−1 as compared with the exfoliated MoS2 (70 F g−1) and exfoliated graphene (85 F g−1) at a current density of 0.1 A g−1 [72]. The high specific capacitance of MoS2/graphene composite is due to the synergistic effect between MoS2 and graphene. Ali *et al.* demonstrated the electrochemical performance of MoS2/CNT/GNF composite and compared the performance with MoS2/CNTs, MoS2/graphene nanoflakes [73]. It has been noticed that the electrochemical charge storage performance has been improved by incorporation of the carbon materials into the composite and the composite showed a maximum specific capacitance of 104 F g−1 at a current density of 0.5 A g−1 with capacitance retention of 75% after the 1000 cycle at a scan rate of 10 mV/s. Another interesting MoS2 rGO/MWCNT fiber electrode was fabricated by incorporating rGO nanosheets and MoS2 into aligned MWCNT, which operated at a stable potential window of 1.4 V and exhibited high coulombic efficiency of 100% over 7000 cycles in the bending state (**Figure 7(b-f )**) [74]. Zhang *et al.* reported an agarose induced technique to synthesize MoS2/carbon composite aerogel, which showed a high specific capacitance of 712.6 F g−1 at a current density of 1 A g−1 with cyclic stability of 97.3% over 13000 charge-discharge cycles (**Figure 7(g-j)**) [75]. The high specific capacitance of MoS2/carbon composite aerogel is because of 3D intercalated network with hierarchal porous and interlayer MoS2 expanded structures, which were beneficial for easy ion transportation. 3D graphene/MoS2 composite electrode material has been synthesized by Sun et al and co-workers through a simple and facile one-step hydrothermal process [76]. The as-synthesized composite electrode exhibited

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*Carbon-Based Nanocomposite Materials for High-Performance Supercapacitors*

gravimetric capacitance of 410 F g−1 at a current density of 1 A g−1 and an excellent cycling stability of 80.3% over 10,000 continuous charge-discharge cycles at 2 A g−1 current density. The outstanding electrochemical performance of 3D graphene/ MoS2 composite electrode is due to the 3D architecture of conducting network graphene and flower-like structure of MoS2, which enhances the electrolyte ions

WS2 nanoplates supported on carbon fiber cloth (WS2/CFC) have been synthesized by a facile solvothermal process and used as electrode material for SC [77]. The 3D network of CFC not only prevent the agglomeration of WS2 nanoplates but also enhances the ion transport efficiency due to low charge transfer resistance (Rct) of 0.1 Ω. The as fabricated WS2/CFC electrode exhibited a high specific capacitance of 399 F g−1 at 1 A g−1 current density with cyclic retention of 99% over charge-discharge 500 cycles, which is higher than compared with bare WS2. In addition, developing such composite of WS2 with the carbon fibre helps for fabricating wearable SCs which are in demand for wearable electronics. Yang *et al.* fabricated WS2@CNT hybrid film electrode by incorporating conducting CNTs into WS2. The WS2@CNT hybrid film with a unique skeleton structure showed a maximum specific area capacitance of 752.53 mF cm−2 at a scan rate 20 mV s−1 with very good cyclic stability by only loss of 1.28% capacitance after 10,000 cycles. In addition, a quasi-solid-state flexible SC made by WS2@CNT hybrid film exhibited excellent bendability under bending to 135 10, 000 times with the loss of 23.12% at scan rate of 100 mV s−1 [53]. Tu *et al.* have been synthesized WS2/RGO hybrid material by using a simple molten salt process, which showed a high specific capacitance of 2508.07 F g−1 at 1 mV s−1 scan rate with excellent capacitance retention of 98.6% over 5000 cycles, due to synergic effect of highly conducting RGO and large charge-accumulating sites of WS2 networks. Likewise, Xu *et al.* demonstrated 3D composite of WS2 nanoflakes and quantum dots on N and S co-doped reduced graphene oxide (WS2/N,S-rGO) crumpled nanosheets through a rapid solution combustion synthesis of the precursor and subsequent gas-solid phase sulfurization process, which presented a significant specific capacitance of 1562.5 F g−1 at 1 A g−1 current density, and a rate capability of 780 F g−1 at 40 A g−1 (**Figure 8(a-c)**) [78]. The high specific capacitance of WS2/N,S-rGO hybrids is because of synergistic effect between WS2 and N,S-rGO, where N,S-rGO provides larger contact surface area, excellent charge transport, and shorter ion diffusion path. Hierarchical MoSe2/C hybrid was successfully fabricated by facile one-step hydrothermal strategy, which composed of few-layered MoSe2 nanosheets and amorphous carbon obtained from the decomposition of the triethylene glycol. As fabricated hierarchical MoSe2/C electrode exhibited high specific capacitance of 878.6 F g−1 in comparison with the bare MoSe2 at current density of 1 A g−1 and maintained 98% of initial capacitance over 2000 cycles without obvious decrease. The superior electrochemical performances of MoSe2/C hybrid can be ascribed to hierarchical structure of MoSe2 and conducting nature of carbon, which help for providing large surface area for electrochemical reactions and enhancing charge carriers transfer at the electrolyte/electrode interface [79]. Liu *et al.* fabricated VACNTF@MoSe2/NF composite electrode through a combined chemical vapor deposition method and solvothermal methods by growing MoSe2 nanoflakes on the vertically aligned carbon nanotube array film (VACNTF) with binder-free nickel foam as current collector [80]. The as fabricated VACNTF@MoSe2/NF composite electrode exhibited high specific capacitance of 435 F g−1 at a current density of 1 A g−1 with outstanding cycling stability

*DOI: http://dx.doi.org/10.5772/intechopen.95460*

**6.2 Carbon-WS2 composite electrode materials**

diffusion process.

#### *Carbon-Based Nanocomposite Materials for High-Performance Supercapacitors DOI: http://dx.doi.org/10.5772/intechopen.95460*

gravimetric capacitance of 410 F g−1 at a current density of 1 A g−1 and an excellent cycling stability of 80.3% over 10,000 continuous charge-discharge cycles at 2 A g−1 current density. The outstanding electrochemical performance of 3D graphene/ MoS2 composite electrode is due to the 3D architecture of conducting network graphene and flower-like structure of MoS2, which enhances the electrolyte ions diffusion process.
