Direct Growth of 3 D Hierarchical Porous Ni₃S₂ Nanostructures on Nickel Foam for High‐Performance Supercapacitors

Abstract

Hierarchicaln anostructures grown on conductive 3D scaffold materials are excellent candidates for supercapacitor electrodes. Herein, we report the fabrication and electrochemical performance of 3D Ni 3 S 2 nanoporous structures directly grown on nickel foam via af acile and cost-effective one-step process using Ni foam as both the template and Ni source. An ultrahigha real capacitance of 7.25 Fcm À2 was obtained at ac urrent density of 5mAcm À2 for the nanoporous Ni 3 S 2 structures. The encouraging performance of Ni 3 S 2 nanoporous structures allowed for the fabrication of asymmetrics upercapacitors (ASCs) using Ni 3 S 2 as cathode and activated carbon as anode. The resulting ASC exhibited high volumetric capacitance (4.48 Fcm À3 at 6mAcm À2 ), high energy density (1.54 mWh cm À3 at ap ower density of 0.07 Wcm À3 ), and excellent cycling stability (92.7 %r etention of the initial capacitance after 5000 cycles at ac urrent density of 16 mA cm À2 ).Recently,t ransition metal sulfides (CuS x ,C oS x and NiS x )h ave received intensive interesta ss upercapacitora ctivem aterials since they have excellent intrinsic chemical and physicalp roperties (higher electrical conductivity,a nd mechanical and thermal stability than their corresponding metal oxides) and good electrochemical performance. [4] Nickels ulfides, which can exist as NiS, NiS 2 ,N i 3 S 2 ,N i 6 S 5 ,N i 7 S 6 and Ni 3 S 4 phases, constitute ac onsiderable portion of transition metal sulfides and have been widely investigated due to av arietyo fp otential applications, such as supercapacitors, photovoltaic cells, rechargeable batteries and photocatalysts. [5] Among all nickel sulfides, Ni 3 S 2 is particularly of interest. It is an abundant and cheap material because it exists as heazlewoodite mineral in nature and possessesh igh theoretical capacity and good conductivity.N i 3 S 2 with variousm orphologies including nanoparticles, nanorods, nanosheets, dendrites and hollow nanospheresh ave been synthesized to date and these nanostructures have been reported to display high capacitive performance in supercapacitor application. [6] For example, Zhang et al. synthesized bacteria reduced graphene oxide/nickels ulfide networks on nickel foam (NF). [7] The networks exhibitedaspecificc apacitance of 1424 Fg À1 at 0.75 Ag À1 ,a nd 67.5 %o ft he capacitance was retained when the currentw as increased from 0.75 to 15 Ag À1 . Zhang and coworkers reportedh ydrothermals ynthesis of Ni 3 S 2 /graphene nanosheets on NF and employed the nanocomposite as as upercapacitore lectrode material. The electrode exhibited 1420 Fg À1 at 2Ag À1 with ah ighc ycle life. [8] Most recently,N i 3 S 2 nanoparticles were grown on graphene coatedN Ft hrough hydrothermal method and displayedaspecific capacitance of 3296 Fg À1 . [9] However,t he electrode could only retain 74 %o fi ts initial capacitance after 1000 cycles and the graphene coating process requires at emperature as high as 1000 8C. Similarly,Z hou et al. synthesized Ni 3 S 2 ,[a] G.Supporting information and the ORCID ...

Facile In Situ Synthesis of Co(OH)2–Ni3S2 Nanowires on Ni Foam for Use in High-Energy-Density Supercapacitors

“…Ni 3 S 2 and Co 0.5 -Ni 3 S 2 showed retention rates of 83.7% and 95.4%, respectively, up to 1000 cycles, indicating that the core-shell structure improves the long-term electrochemical stability of the KOH electrolyte system. The optimal SC and cycling performance of the electroactive Ni 3 S 2 electrode are superior or comparable to those of previously reported Ni 3 S 2 electrodes (Table 1) [25,[64][65][66][67][68].…”

NiF2 Nanorod Arrays for Supercapattery Applications

“…At 1, 5, 10, 15, and 25 mV s –1 scan rates, the areal specific capacitances (ASC) of the NiF 2 @Ni NA were respectively 51, 13, 9, 7, and 5 F cm –2 , which is ascribed to a reduction in the migration speed of ions for redox reactions, as at higher scan rates and accessibility of inner active sites is limited. , Because of a high surface area and a mechanically robust adhesion with lowered interfacial resistance to the underlying Ni, the self-grown mesoporous NiF 2 @Ni NA offers more accessible sites for redox reactions compared to polished Ni and similar nanostructured electrode materials of various composition and morphologies on Ni (see Table S1 of the Supporting Information). The inner/outer surface contributions to the ASC of NiF 2 @Ni NA compared to Ni are shown in inset of Figure a, where we consistently observe a higher amount of charge (typically a factor of ∼2× greater) is stored on the NiF 2 @Ni NA (for more details see the Supporting Information Figure S3a,b). − For both electrodes, at the initial potential of 0.2 V (vs Hg/HgO), the slope of 0.2 increased to 0.45 and reached 0.5 (indicating a diffusion-limited intercalative process) at potentials >0.4–0.5 V, indicating that NiF 2 @Ni NA behaves as a battery-type material (see Figure S3c,d for more details) . Taken together, the intercalation capacitive contribution was more than 90% in both electrodes, signifying its dominance in the ASC performance (Figure S3e–h, Supporting Information) with higher values obtained for the NiF 2 nanorod coating.…”

“…Developing abundant, robust, scalable, and greener chemical routes for metal-oxides/hydroxides/carbides/nitrides/phosphides/layered double hydroxides etc., has seen some promising developments for both battery electrode materials. , We provide a comparison of recently published data on ECS application using Ni­(OH) 2 , NiO, Ni x S y , NiTe, NiSe, and so forth, electrodes, developed by simpler chemical reduction or electroless methods among others, − in Figure , with further details on performance (capacitance) and related data provided in the Supporting Information, Table S1. Electrode materials grown by displacement, reduction, or electroless processes, for example, with high surface area and a strong mechanical adhesion to the underlying substrate material tend to offer better performance than metal salt or binder inspired hydrothermally/chemically grown electrodes, although much of the improvement tends to be a geometrical enhancement, rather than an intrinsic one.…”

In situ moulded troilite 2H phase FeS ultrathin electrodes via pulsed laser deposition for flexible solid state high capacity supercapacitor besides boosted electrocatalytic oxygen evolution reaction

“…3h, and it is superior to earlier reports. 18,65,66 Finally, the stability performance of the FeS (A650) thin lm electrode was tested to study the GCD cyclic performance at a current rate of 0.7 mA cm −2 and a corresponding electrode attained a notable capacitance retention of 89% with a round trip efficiency of about 94% over 5000 cycles, as presented in Fig. 3i.…”