Potentiodynamic deposition of composition influenced Co1−xNix LDHs thin film electrode for redox supercapacitors
Highlights
► Co1−xNix layered double hydroxides by potentiodynamical mode. ► The Co1−xNix LDHs thin film electrodes as redox supercapacitor with specific capacitance ∼ 1213 F g−1. ► Highly electrochemical cyclic stability retained 77% after 10,000th cycle. ► Co0.66Ni0.34 LDHs showed specific energy = 104 W h kg−1, specific power = 1.44 kW kg−1 and coulomb efficiency ∼94%.
Introduction
Supercapacitors are the mostly studied electrochemical devices in the energy storage research field. Supercapacitors have very high specific power and higher charge/discharge rate than the existing secondary batteries [1], [2], [3]. They arouse wide concern by researchers, but their low specific energy restricts them to be used as power sources alone. Nanomaterials are rapidly developing and have been widely used in lots of fields because of their outstanding advantages in science and technology. Currently, many more materials are potential contenders as electrode materials for supercapacitor function. Such as activated carbon (AC), carbon aerogels, carbon nanotubes as electric double layer capacitors (EDLCs) electrode; transition metal oxides/hydroxides, conducting polymers as pseudocapacitive (redox) electrodes, etc [4], [5], [6]. Kang et al. recently reported exceed charge/discharge current of the ion-exchange based electrode material [6], [7]. Therefore, further breakthroughs in materials are essential. In this regard, the nanostructured layered double hydroxide LDH) materials open up a new important avenue in the advancement of the science and technology [8]. Nanomaterials bring us the advantages of higher electrode/electrolyte contact area, short path lengths for cation transport, high power performance and new reactions, which are not possible with bulk materials [9], [10], [11]. The existing nano-size electrode materials have higher specific mass capacity in the process of charge/discharge than the general micro size electrode material. It has been reported in recent years that some nanostructured electrode materials obtain good charge/discharge capacity [13], [14].
Current advances of metal hydroxides, especially layered double hydroxides with very high specific capacitances have regenerated great interest in such materials. Mainly, Co(OH)2 and Ni(OH)2 are strong contenders as an electrode materials having very high specific capacitances due to their layered structures with large interlayer spacing and characteristic redox reaction. Recently Gupta et al. prepared CoxNi1−x LDHs by the potentiostatically and reported a maximum specific capacitance of 2104 F g−1 however; in this case the potential window is only 0.4 V [11]. Also Hu et al. synthesized CoxNi1−x LDHs by a chemical co-precipitation route using polyethylene glycol and obtained maximal specific capacitance of 1809 F g−1 in 6 M KOH electrolyte [12].
In this work, for the first time we reported the synthesis of Co1−xNix LDHs thin films as supercapacitor electrode material via potentiodynamic mode (cyclic voltammetry) in aqueous media. The effect of composition variation of Co and Ni on structural, morphological, wettability and supercapacitive properties of Co1−xNix LDHs thin films along with their stability and charging–discharging characteristics are performed. This work will investigate the correlations between its chemical composition and structural, morphological, surface wettability and electrochemical capacitive characteristics in detail, and confirm that the Co1−xNix LDHs are strong supercapacitor electrode material. The results reported here will help to modify and engineer LDH materials accordingly the energy application.
Section snippets
Experimental
Analytical grade chemicals Co(NO3)2·6H2O, Ni(NO3)2·6H2O and research grade stainless steel (SS, grade 304) were used for the deposition of Co1−xNix LDHs thin films. The stainless steel substrate was polished with emery paper to a rough finish, washed with double distilled water and make free of abrasive particles and then air dried. For the deposition of Co1−xNix LDHs films; aqueous baths of 0.1 M solutions of Co(NO3)2, Ni(NO3)2 at pH ∼6 were used. The suitable composition of Co1−xNix LDHs was
Film formation
Fig. 1 shows voltammograms recorded for 0.1 M solutions of Ni(NO3)2, Co(NO3)2 and Co(NO3)2 + Ni(NO3)2 at bath compositions 0.0:1.0, 1.0:0.0 and 0.5:0.5 on stainless steel substrate, respectively. The possible redox reactions are given below. During electrodeposition from aqueous solution of Co(NO3)2:Ni(NO3)2 at negative potentials, nitrate ions can be reduced (E0 = −200 mV/SCE) on the cathodic surface to produce hydroxide ions. The generation of OH− at the cathode raises the local pH, as follow
Conclusions
The nanostructured porous Co1−xNix layered double hydroxides (Co1−xNix LDHs), which exhibit both Co(OH)2 and Ni(OH)2, have been successfully deposited in the thin film form by potentiodynamic mode owing randomly oriented nano-flakes like morphology and superhydrophilic characteristics. The increase of Ni content (x = 0, 0.34, 0.46, 0.59, 0.76 and 1) in Co1−xNix LDHs affects emerging surface morphological aspect. Maximal specific capacitance for Co1−xNix LDHs electrode was found ∼1213 F g−1,
Acknowledgment
Authors are grateful to the Council for Scientific and Industrial Research (CSIR), New Delhi (INDIA) for financial support through the scheme. No. 03(1165)/10/EMR-II.
References (37)
- et al.
Preparation of nanostructures NiO and their electrochemical capacitive behaviours
Int J Hydrogen Energy
(2009) - et al.
Synthesis, characterization, and electrochemical properties of ultrafine b-Ni(OH)2 nanoparticles
Int J Hydrogen Energy
(2011) - et al.
Enhanced electrochemical performance of nickel hydroxide electrode with monolayer hollow spheres composed of nanoflakes
Int J Hydrogen Energy
(2011) - et al.
Fabrication and electrochemical characterization of two-dimensional ordered nanoporous manganese oxide for supercapacitor applications
Int J Hydrogen Energy
(2012) - et al.
Cyclic voltammetric studies of pure and doped films of cobalt hydroxide in 1 M KOH
J Power Sources
(1991) - et al.
Synthesis of Co(OH)2/graphene/Ni foam nano-electrodes with excellent pseudocapacitive behavior and high cycling stability for supercapacitors
Int J Hydrogen Energy
(2012) - et al.
Potentiostatically deposited nanostructured CoxNi1−x layered double hydroxides as electrode materials for redox-supercapacitors
J Power Sources
(2008) - et al.
Synthesis and electrochemical characterization of mesoporous CoxNi1−x layered double hydroxides as electrode materials for supercapacitors
Electrochim Acta
(2009) - et al.
Chimie douce reactions: a new route to obtain well crystallized layer double hydroxides
J Solid State Chem
(1993) - et al.
Formation of layered single- and double-metal hydroxide precipitates at the mineral/water interface: a multiple-scattering XAFS analysis
J Colloid Interface Sci
(2000)
Cyclic voltammetric studies of stabilized α-nickel hydroxide electrode
J Power Sources
Technological implications in studies of nickel electrode performance and degradation
J Power Sources
Interconnected β-Ni(OH)2 sheets and their morphology-retained transformation into mesostructured Ni
Solid State Commun
Development of ultra-battery for hybrid-electric vehicle applications
J Power Sources
Electrochemical capacitor thermal management issues at high-rate cycling
Electrochim Acta
Carbon materials for the electrochemical storage of energy in capacitors
Carbon
Chemically deposited nanocrystalline NiO thin films for supercapacitor application
Appl Surf Sci
High-power alkaline Zn–MnO2 batteries using c-MnO2 nanowires/nanotubes and electrolytic zinc powder
Adv Mater
Cited by (86)
Robust CoP@NiFe LDH/Ni heterostructured electrodes for efficient overall water splitting with high current density
2024, Journal of Alloys and CompoundsHoneycomb nickel-cobalt layered double hydroxides supported on carbon skeleton as high-performance electrodes in supercapacitors
2023, Journal of Alloys and CompoundsStudy on electrochemical properties of cobalt-nickel alloy prepared by pulsed electrodeposition
2023, International Journal of Electrochemical ScienceActivation-induced layered structure in NiCoAl by atomic modulation for energy storage application
2023, Materials Today ChemistryCitation Excerpt :These issues can be addressed by stimulating the alloys using KOH electrolytes to generate copious active sites and to promote charge accumulation, chemical stability, and fast ion transport leading to layered double hydroxides (LDHs) formation. Bimetallic LDHs have been used for the enhancement of specific capacitance due to high redox activities [23–27]. Moreover, the advantages of the LDHs are high ionic interaction, ion diffusion, transport kinetics of ions/electrons, redox activity, and chemical stability that are responsible for the enhancement of electrochemical charge storage performance [28].