Lichen-like anchoring of MoSe on functionalized multiwalled carbon nanotubes: an efficient electrode for asymmetric supercapacitors.

In the present study, we have developed a composite electrode of MSNT using a simple and scalable two-step scheme to synthesize a composite electrode material comprising MoSe/multiwalled carbon nanotubes (MoSe/MWCNTs) for supercapacitor applications. First, a MWCNT thin film was deposited on a stainless steel substrate by using a "dip and dry" coating technique. Subsequently, MoSe was deposited onto the MWCNT thin film using the successive ionic layer adsorption and reaction method. The lichen-like growth of MoSe on the MWCNT network provided dual charge storage and an effective ion transfer path. The composite electrode of MSNT has been studied systematically with different electrolytes and concentrations of electrolyte. As a result, the MoSe/MWCNT (MSNT) electrode exhibited excellent electrochemical properties such as a specific capacity of 192 mA h g and a capacitance retention of 88% after 2000 cycles in 1 M LiCl electrolyte. The results demonstrated the huge potential of the MSNT composite electrode for practical application in supercapacitors. The aqueous symmetric cell fabricated using the MSNT composite as both the anode and cathode showed an energy density of 17.9 W h kg. Additionally, the energy density improved by designing an asymmetric device of MSNT//MnO and notably, it reveals two-fold improvement in the energy density compared to a symmetric MSNT cell. The MSNT//MnO-based asymmetric cell exhibited a maximum specific capacitance of 112 F g with a high energy density of 35.6 W h kg.