Fabrication of Porous Mesh‐Like FeCo₂S₄ Nanosheet Arrays on Ni Foam for High Performance all Solid‐State Supercapacitors and Water Splitting

Abstract

Porous mesh‐like FeCo2S4 nanosheet arrays on Ni foam (NF) have been prepared by a two‐step hydrothermal approach and employed as electrodes for supercapacitors and efficient bifunctional electrocatalysts for water splitting. FeCo2S4/NF exhibits ultrahigh areal capacitance of 7.37 F cm−2 at current density of 5 mA cm−2 and achieves good cycling stability retaining 92% capacitance after 3000 cycles at 10 mA cm−2. Symmetric solid‐state device of FeCo2S4/NF as positive and negative electrodes delivers a remarkable energy density of 19.12 W h kg−1 (434.61 W kg−1). Furthermore, FeCo2S4/NF electrode delivers a low overpotential of 155 mV at a hydrogen evolution reaction (HER) current density of 10 mA cm−2 and shows no obvious attenuation after stability test for 100,000 s in 1 M KOH solution. While a low overpotential of 234 mV at 50 mA cm−2 for oxygen evolution reaction (OER) can be demonstrated in alkaline environment as an anode electrocatalyst. FeCo2S4/NF shows excellent activity toward overall water splitting with 10 mA cm−2 by applying just 1.405 V across the two electrodes. Hence, the porous mesh‐like FeCo2S4 nanosheet arrays on Ni foam are promising electrode materials for supercapacitor application and water splitting.

FeCo2S4@Ni@graphene Nanocomposites with Rich Defects Induced by Heterointerface Engineering for High-Performance Supercapacitors

“…The deconvoluted peaks of Fe 2p 3/2 at the bonding energies of 707.1, 710.3, and 712.3 eV are correlated to Fe 0 , Fe 2+ , and Fe 3+ , respectively. , Specifically, the ratio of Fe 3+ /Fe 2+ in the nanocomposite is calculated to be 4.0, which is notably higher than that of FeCo 2 S 4 (1.4). In the Co 2p spectra (Figure e,f), the deconvoluted peaks at 781.2 and 796.2 eV are ascribed to Co 2+ , while the peaks at 778.5 and 793.5 eV are attributed to Co 3+ . , As opposed to iron, the ratio of Co 3+ /Co 2+ decreases from 1.21 for FeCo 2 S 4 to 1.06 for the nanocomposite. In the S 2p spectra (Figure g,h), the deconvoluted peaks at 161.6 and 162.7 eV are assigned to S 2p 3/2 and S 2p 1/2 , respectively, corresponding to the presence of S 2– species.…”

“…In the Co 2p spectra (Figure 3e,f), the deconvoluted peaks at 781.2 and 796.2 eV are ascribed to Co 2+ , while the peaks at 778.5 and 793.5 eV are attributed to Co 3+ . 13,37 As opposed to iron, the ratio of Co 3+ /Co 2+ decreases from 1.21 for FeCo 2 S 4 to 1.06 for the nanocomposite. In the S 2p spectra (Figure 3g,h), the deconvoluted peaks at 161.6 and 162.7 eV are assigned to S 2p 3/2 and S 2p 1/2 , respectively, corresponding to the presence of S 2− species.…”

“…The three-dimensional (3D) structural FeCo 2 S 4 exhibited a higher specific capacity as compared with one-dimensional (1D) and two-dimensional (2D) electrodes . Ma et al prepared the porous mesh-like FeCo 2 S 4 nanosheet arrays with areal capacitance of 7.37 F cm –2 at 5 mA cm –2 …”

“…12 Ma et al prepared the porous mesh-like FeCo 2 S 4 nanosheet arrays with areal capacitance of 7.37 F cm −2 at 5 mA cm −2 . 13 Designing multicomponent materials and constructing multilevel nanostructures are two common strategies for developing high-performance electrode materials. The hierarchical nanostructures can enrich the electroactive sites, shorten the ion transport pathways, and enhance the structural stability, thereby effectively improving the utilization of electrode materials.…”

Fe‐doped CoNi0.5P Hierarchical Arrays as Efficient Bifunctional Electrocatalysts for Overall Water Splitting: Evolution of Morphology and Coordination of Catalytic Performance

“…The major obstacle which hampers the widely commercial application of water splitting is still lie in lacking of high‐efficient and durable bifunctional catalysts for both OER and HER . At present, precious metal‐based electrocatalysts including Pt (Pt/C or Pt alloys) and Ir/Ru oxides are considered to be the most active and efficient catalysts for HER and OER, but the scarcity and high cost greatly limited their practical application . Therefore, it is highly desirable to explore cheap and high activity bifunctional electrocatalysts based on earth‐abundant elements as alternatives to Pt and Ir/Ru oxides for both HER and OER.…”