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The ongoing demand for supercapacitors with high energy density, stability, and a wide range of working potential for device applications is a great challenge to researchers. In this study, we have explored suitability of nanocomposites based on functionalized BNs (mK-BN/mH-BN), CNTs, and polyaniline (PANI) as supercapacitor electrodes to address this demanding issue. We have also focused on the enhancement of the electrochemical activity of BN with surface functionalization. FTIR and XPS analysis confirmed successful incorporation of oxygen functionality on the BN surface. Morphological analysis indicated exfoliation of BN after modification and homogeneous growth of PANI-coated CNTs on exfoliated modified BN. Among the ternary nanohybrids, the mK-BN/CNT/PANI composite achieved highest specific capacitance of 515 F g−1 and an energy density of 46 W h kg−1 in a three-electrode system. Furthermore, cyclic stability of mK-BN/CNT/PANI is found to be ∼98% after the completion of 10 000 charging–discharging cycles. For device application, the mK-BN/CNT/PANI based asymmetric supercapacitor showed efficient electrochemical activity with an enhanced energy density of 62 W h kg−1 and capacitance retention of ∼91% after 5000 cycles. The comparative electrochemical efficiency of the electrode material has also been examined in two different organic electrolytes. All these excellent electrochemical characteristics demonstrated the high potentiality of mK-BN/CNT/PANI for real-time supercapacitor applications. [ABSTRACT FROM AUTHOR]

Boron nitride's (BN) large band gap does not permit carrier transport at ambient conditions. We show that BN sheets can be exfoliated by functionalization with oxy-groups to introduce additional acceptor and donor energy levels appropriate for energy storage devices. Further, the incorporation of heteroatoms into transition metal sulfides enhances capacitance via Faradic redox reactions and their cyclic stability. The functionalized boron nitride (m K -BN) and Carbon Nanotubes (CNTs) are intertwined with a Zn-doped Cadmium-Sulfide (Zn–CdS) nanostructure to increase the surface area-charge storage. In a supercapacitor application, Zn–CdS/m K -BN/CNT exhibits a 787 F/g specific capacitance (SC) in an aqueous (aq.) electrolyte. Further, the Zn–CdS/m K -BN/CNT was deployed as a cathode material in an asymmetric supercapacitor device (ASC) coupled with an ionic electrolyte (IE), (NHEt 3)+(NO 3)−, offered a SC of 173 F/g with an approximate 99% stability due to the enhanced charge mobility. The reported functionalization of BN induces additional energy levels making the material ideal for energy storage devices and will directly impact the next-generation of advanced supercapacitor electrode materials. [ABSTRACT FROM AUTHOR]

Abstract Single pot solvothermal synthetic procedure was followed for easy synthesis of n-TiO 2 /n-Gr composite for supercapacitor. FTIR, XRD, XPS and FESEM were executed to access the chemical nature, interaction, growth and morphology of the samples. In both three and two electrode arrangement, n-TiO 2 /n-Gr leads to 937.5 F/g and 633.75 F/g specific capacitance (SC) respectively. Enhanced SC may be due to facile electron carry-over in n-TiO 2 deposited n-Gr surface. This superior SC complemented with high energy density (ED) of 46.25 Wh/kg and power density (PD) 3999.51 W/kg. This composite also retains about 87% retention of SC after 5000 successive charge–discharge rounds. However, in organic electrolyte (1 M TEABF 4 in acetonitrile) with two-electrode testing configuration, the composite showed an energy density of 225.33 Wh/kg with high power density of 1599.7 W/kg. N doped in both TiO 2 and graphene enhanced the compatibility and electrochemical performances of electrode material and makes it a potential candidate for supercapacitor. Graphical abstract Image 1 Highlights • The paper first time reported template free, facile synthesis of n- TiO 2 /n-Gr composite. • The n- TiO 2 /n-Gr showed specific capacitance 937.5 Fg-1 at 0.6 A g−1. • Electrochemical study is performed in both three and two electrode system. • The two-electrode system shows a high energy density 225.33 W h Kg−1 at 1 A g−1. • 87% retention of specific capacitance also exhibited even after 5000 cycles of GCD. [ABSTRACT FROM AUTHOR]

Alternative finding of toxic pollutant materials in proper utilization is a great challenge. Toxic and pollutant cigarette smoke having different π-conjugated organic components may work well as a precursor for carbon dots (CDs). In this work, cigarette smoke aerosol has been used for the synthesis of CDs and CDs have been further used for the fabrication of supercapacitor electrode. This methodology could be able to mitigate the two major problems-energy crisis and environment pollution. The smart combination of EDLC-type CDs deposited boron nitride (BN) and pseudocapacitive type Zn-doped MoS 2 was able to enhance the supercapacitive performances. Heteroatom doping into MoS 2 enhances the capacitive performances through the effective Faradic reactions. CDs and CDs deposited BN (CDs@BN) have been characterized using different characterization techniques. Zn-doped MoS 2 has been uniformly grown on the CDs decorated BN (Zn–MoS 2 /CDs@BN) resulting in the stabilization of the electrode system. Zn–MoS 2 /CDs@BN nanohybrid delivered a specific capacitance (Sp.C) of 397 F/g in three-electrode system. Further, the asymmetric supercapacitor (ASC) device using Zn–MoS 2 /CDs@BN as cathode demonstrated wide potential range (up to 1.8 V) with a volumetric energy density of 3.42 mW h/cm3 and retaining a capacitance of ∼89% after 10,000 charging-discharging processes. Moreover, a flexible ASC device was made-up using viscous ionic electrolyte and it was able to glow a red LED, while it was bended in different angles. The methods described here will give a straightforward approach for using toxic-pollutant cigarette smoke to fabricate supercapacitor electrodes in order to compensate the upcoming energy crisis in a sustainable way. Cigarette smoke aerosol derived carbon dots decorated boron nitride supported Zn-doped MoS 2 for high performance flexible asymmetric supercapacitor device in low-cost viable ionic electrolyte. [Display omitted] • For waste to wealth perspective, synthesis of CDs using toxic pollutant cigarette smoke aerosol for flexible asymmetric supercapacitor device. • Synthesis of CDs induced BN supported Zn-doped MoS 2 using a facile hydrothermal method for the enhancement of electrochemical efficiency. • Zn–MoS 2 /CDs@BN, as positive electrode for the asymmetric supercapacitor achieved an enhanced energy density of 119 W h/kg with ∼91% retention of specific capacitance. • ASC device revealed decent volumetric energy density of 3.42 mW h/cm3. • Fabrication of flexible asymmetric supercapacitor in low-cost viable ionic electrolyte. [ABSTRACT FROM AUTHOR]