Nitrogen-doped graphene encapsulated cobalt iron sulfide as an advanced electrode for high-performance asymmetric supercapacitors

Abstract

A novel core–shell Co8FeS8@NG hybrid was synthesized through a simple, cost effective, single-step in situ hydrothermal process, exhibiting superior electrochemical performance as advanced electrode materials in solid-state supercapacitors.

Enhanced Supercapacitive Performance of Higher-Ordered 3D-Hierarchical Structures of Hydrothermally Obtained ZnCo2O4 for Energy Storage Devices

“…The former was assigned to the Zn 2p 3/2 state, while the latter corresponds to the Zn 2p 1/2 state, signifying the presence of Zn 2+ in the normal state in the as-prepared ZCO samples. The binding energy variation between the spin–orbit interaction of the Zn 2p 3/2 and Zn 2p 1/2 states was projected as 23 eV, which is reliable with the earlier reports [ 39 , 40 , 41 ]. Similarly, the Co 2p core-level spectra of all the samples are displayed in Figure 5 c.…”

“…Specific capacitance ( C s in F·g −1 ) values for ZCO-6h and ZCO-12h were calculated based on the following equation for a nonlinear charge/discharge curve [ 39 ]: where I is the current of discharge curve in mA, ∫ V d t is the area under the discharge curve in V.s, V f − V i is the potential difference between final and initial voltage in volts (v) and m is the active electrode mass in grams (g). Based on the above equation, the specific capacitances of ZCO-6h and ZCO-12h were calculated as approximately 359.85 F·g −1 (28.78 C·g −1 ) and 421.05 F·g −1 (31.52 C·g −1 ) at 1 A·g −1 , respectively.…”

“…Clearly, ZCO-12h exhibits a slightly higher time response than that of the ZCO-6h electrode. Specific capacitance (Cs in F•g −1 ) values for ZCO-6h and ZCO-12h were calculated based on the following equation for a nonlinear charge/discharge curve [39]:…”

Efficient production of hydrogen from H2Sviaelectrolysis using a CoFeS2catalyst

“…1j constituted two spin-orbit doublets wherein Co 2p 3/2 peaks at 779.1 and 781.3 eV and the peaks of Co 2p 1/2 at 794.3 and 797.1 eV are characteristic of Co 2+ and Co 3+ respectively, along with two satellite peaks at 786.1 and 803.2 eV. 55,56 Similarly, the Fe 2p XPS spectra in the region of 730–700 eV deconvoluted into two doublets at 710.9 and 723.8 eV corresponding to Fe 2p 3/2 and Fe 2p 1/2 attributed to Fe 2+ while the peaks at 713.4 and 725.6 eV can be ascribed to Fe 3+ , indicating that Fe is present in +2 and +3 oxidation states (Fig. 1k).…”

A multifunctional cobalt iron sulfide electrocatalyst for high performance Zn–air batteries and overall water splitting

“…Besides, two additional satellite peaks at 786.1 and 803.2 eV are also observed in Co 2p spectra. 62,63 Similarly, the Fe 2p XP spectra deconvoluted into two doublets due to spin–orbit coupling. The peaks at 711.0 and 723.8 eV are attributed to Fe 2+ while the peaks at 713.5 and 725.6 eV are ascribed to Fe 3+ signifying that the Fe is present in +2 and +3 oxidation states, respectively (Fig.…”