Incorporation of Carbon Quantum Dots for Improvement of Supercapacitor Performance of Nickel Sulfide

Abstract

A facile hydrothermal method is adopted for the synthesis of hierarchical flowerlike nickel sulfide nanostructure materials and their composite with carbon quantum dot (NiS/C-dot) composite. The composite material exhibited good performance for electrochemical energy-storage devices as supercapacitor with a specific capacity of 880 F g –1 at a current density of 2 A g –1 . The material remained stable up to the tested 2000 charge–discharge cycles. Carbon quantum dots of size 1.3 nm were synthesized from natural sources and the favorable electronic and surface property of C-dots were utilized for improvement of the supercapacitor performance of NiS. The results from Tafel analysis, double-layer capacitance, and the impedance measurement reveal that the incorporation of C-dots inside the NiS matrix has improved the charge-transfer process, which is mainly responsible for the enhancement of the supercapacitive property of the composite materials.

Direct solvent free synthesis of bare α-NiS, β-NiS and α-β-NiS composite as excellent electrocatalysts: Effect of self-capping on supercapacitance and overall water splitting activity

“…The peaks located at 853.4 and 871.4 eV can be assigned to the Ni 2p 3/2 and Ni 2p 1/2 states of Ni 2+ respectively, whereas those observed at 859.2 and 878 eV are the corresponding satellite peaks (Fig. 5a) 64,65 . For the S 2p spectrum, the peak at 160.8 eV corresponds to S 2p 3/2 , and suggests that the sulfur species in NISE-1 exist as divalent ions (S 2− ).…”

Flexible Molecular Precursors for Selective Decomposition to Nickel Sulfide or Nickel Phosphide for Water Splitting and Supercapacitance

“…This indicates an approximately 3‐fold increase in the charge storage capacity of our orthorhombic NiS sample. Additionally, Sahoo et al . synthesized a nickel sulfide‐based supercapacitor by incorporating carbon quantum dots.…”

“…Likewise, whenN iP-1 and NiP-2 were compared, NiP-1 provided ah igher specific capacitance of 1043 Fg À1 at 0.5 Ag À1 .R ani et al [26] recently investigated a nickel sulfide-basedn anocomposite for its electrochemical per- formance and recordedas pecific capacitance of 428 Fg À1 at 10 mV s À1 whereas our NiS-2 sample gave as pecific capacitance of 1441 Fg À1 at 10 mV s À1 .This indicates an approximately 3-fold increasei nt he charge storagec apacity of our orthorhombic NiS sample. Additionally,S ahoo et al [27] synthesized a nickel sulfide-baseds upercapacitor by incorporating carbon quantum dots.Aspecific capacitance of 880 Fg À1 at ac urrent density of 2Ag À1 was reported, which is much lower than the one of our synthesized NiS-2 sample, which showed as pecific capacitance of 1149 Fg À1 at ac urrent density of 2Ag À1 .T he data clearly show av astly improved electrocatalytic performance of the nickel sulfide samples synthesized in this work. Additionally,t he powera nd energy densities of all the samples were calculated by using galvanostaticc harge-discharge data.…”

One-pot hydrothermal synthesis of molybdenum nickel sulfide with graphene quantum dots as a novel conductive additive for enhanced supercapacitive performance

“…[28][29][30][31][32][33][34][35] There are some recent studies on the effect of GQD inclusion on different types of metal oxides/ sulfides for supercapacitor applications. [36][37][38][39] The synergistic effect is one of the major factors that contribute to the enhanced electrochemical performance of electrodes, whereas transition metal sulfides doped with metals take advantage from each component because nickel and molybdenum sulfides provide richer redox chemistry compared to the corresponding individual binary sulfides, which possess a higher theoretical capacity. To the best of our knowledge, we are the first to report the effect of GQD inclusion on molybdenum doped nickel sulfide (MNS) for supercapacitor applications in a binder-free approach.…”