Electrodeposition of Cu-Doped MoS₂for Charge Storage in Electrochemical Supercapacitors

Abstract

Cu-doped MoS 2 thin films were prepared by one-step electrodeposition from 10.0 mM (NH 4 ) 2 MoS 4 , 5.0 mM CuSO 4 , 0.10 M KCl and 0.50 M KSCN at pH 6.95, followed by annealing for three hr. at 500 • C in Ar. Cyclic voltammetry in the presence of the SCNcomplexing agent yields a cathodic deposition peak that is slightly anodically shifted (∼90 mV) relative to the cathodic deposition peaks observed for elecrolytes containing only Cu 2+ and only MoS 4 2− . This may provide evidence for the induced co-deposition mechanism, but it is unclear which specific compound is formed. According to RBS and EDX analysis, thin film deposits contain 1-4 atom% Cu and are sulfur-deficient relative to stoichiometric MoS 2 . Cu dopant incorporation reduces the film resistivity by ∼10x relative to undoped MoS 2 . The specific capacitaqnce of Cu-doped MoS 2 was also measured by both cyclic voltammetry (CV) and galvanostatic charge-dischrarge (GCD). For 500 nm thick annealed MoS 2 films, the specific capacitance of Cu-doped films ranges from 2.5-3.5x higher than that of undoped films during 1000 cycles of CV testing in 1.0 M Na 2 SO 4 . Capacitance testing also reveals better capacity retention and high scan rate performance for Cu-doped relative to undoped MoS 2 films.

Impedance Biosensing atop MoS2 Thin Films with Mo−S Bond Formation to Antibody Fragments Created by Disulphide Bond Reduction

“…After annealing, the EIS spectra for MoS 2 and Cu−MoS 2 thin films exhibit capacitive Nyqyuist plots that approach a vertical line, which is characteristic of electrochemical supercapacitors . However, after BSA adsorption, both annealed MoS 2 and Cu−MoS 2 thin films exhibit semicircular RC loops that are characteristic of the Randles equivalent circuit, as will be discussed below.…”

“…The Nyquist plots in Figures – exhibit different shapes that reflect the varying nature of these electrochemical interfaces. As previously reported, the annealed MoS 2 and Cu−MoS 2 thin films exhibit the capacitive behavior expected for electrochemical supercapacitors . This explains the nearly vertical lines that are observed in Figures and for MoS 2 and Cu−MoS 2 after annealing at 500 °C in Ar for 3 h. However, the impedance magnitude is small (0–200 Ω‐cm 2 ), so these nearly vertical lines can only be observed in the insets to Figures and .…”

“…During HDS, TMD‐containing catalysts with coordinatively unsaturated Mo sites exhibit a high affinity towards sulphur, allowing TMDs to bind and extract sulphur in various forms from hydrocarbon mixtures, and then catalyse subsequent C‐S bond clevage. The authors observe similar high affinity towards sulphur during electrodeposition of MoS 2 , Cu−MoS 2 and WS 2 from tetrathiometallate precursors . The as‐deposited films contain significant excess sulphur, as shown in Table , indicating that these materials desulphurize the electrolytes from which they are deposited.…”

Influence of Cu on the Performance of Tuberose Architecture of Strontium Hydroxide Thin Film as a Supercapacitor Electrode

“…reported that specific capacitance of FeOOH has increased to 463.18 F g −1 at 0.1 A g −1 current density due to Co doping . Similarly, there are many more reports in which specific capacity increases due to doping …”

“…[19] Similarly, there are many more reports in which specific capacity increases due to doping. [20][21] Recently, Sr(OH) 2 with high specific capacity has been reported but it suffers low cycle stability. [17] Incorporation of certain elements can provide the effective way of enhancing the specific capacity as well as the cycle stability.…”