Al and Co co-doped α-Ni(OH)2/graphene hybrid materials with high electrochemical performances for supercapacitors

Xu, Chen; Long, Conglai; Lin, Changpeng; Wei, Tong; Yan, Jun; Jiang, Lili; Fan, Zhuangjun

doi:10.1016/j.electacta.2014.05.151

Cited by 73 publications

(48 citation statements)

References 43 publications

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“…α-Ni(OH) 2 materials have been prepared with cationic substitutions of the lattice Ni with Al [16,[67][68][69][70][71][72][73][74][75], Mn [76,77], Fe [78,79], Co [14,69,74,75,[80][81][82], Cu [67,83], Zn [65,66,70,84,85], Y [86] and Yb [87]. In some of these examples, the bivalent Ni 2+ cation is replaced with a trivalent species (e.g.…”

Section: (Iii) Ionic Substitution and Foreign Ion Incorporationmentioning

confidence: 99%

Nickel hydroxides and related materials: a review of their structures, synthesis and properties

et al. 2015

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This review article summarizes the last few decades of research on nickel hydroxide, an important material in physics and chemistry, that has many applications in engineering including, significantly, batteries. First, the structures of the two known polymorphs, denoted as α-Ni(OH) 2 and β-Ni(OH) 2 , are described. The various types of disorder, which are frequently present in nickel hydroxide materials, are discussed including hydration, stacking fault disorder, mechanical stresses and the incorporation of ionic impurities. Several related materials are discussed, including intercalated α-derivatives and basic nickel salts. Next, a number of methods to prepare, or synthesize, nickel hydroxides are summarized, including chemical precipitation, electrochemical precipitation, sol-gel synthesis, chemical ageing, hydrothermal and solvothermal synthesis, electrochemical oxidation, microwaveassisted synthesis, and sonochemical methods. Finally, the known physical properties of the nickel hydroxides are reviewed, including their magnetic, vibrational, optical, electrical and mechanical properties. The last section in this paper is intended to serve as a summary of both the potentially useful properties of these materials and the methods for the identification and characterization of 'unknown' nickel hydroxide-based samples.

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Section: (Iii) Ionic Substitution and Foreign Ion Incorporationmentioning

confidence: 99%

Nickel hydroxides and related materials: a review of their structures, synthesis and properties

et al. 2015

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“…V used in this study is 0.5 V. m is the mass of the electrode materials. In order to better compare the performance of amor-Ni(OH) 2 Figure 4 d. To our knowledge, this is one of the highest gravimetric specifi c capacitances among all reported Ni(OH) 2 materials measured using a three-electrode cell [13][14][15]17,20,21,27,[39][40][41][42] (see Table S1, Supporting Information, for detailed comparison), suggesting that effi cient surface redox reactions can take place on the thin Adv. MWCNT/PEDOT:PSS also shows a rectangular-like shape but with a bulge around 0.22 V which is related to the redox reaction of PEDOT.…”

Section: Specifi C Capacitance and Rate Capacity Of The Hybridsmentioning

confidence: 99%

Ternary Hybrids of Amorphous Nickel Hydroxide–Carbon Nanotube‐Conducting Polymer for Supercapacitors with High Energy Density, Excellent Rate Capability, and Long Cycle Life

Jiang

Zhang

et al. 2015

Adv Funct Materials

293

135

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take place on the surface or near-surface region of pseudocapacitive materials is particularly paramount to the development of supercapacitors with both high energy density, high rate capability, and long cycle life.Ni(OH) 2 /NiO(OH) couple is the main redox system used in the positive electrodes of alkaline rechargeable batteries, because of its good reversibility and cyclic behavior. [ 5,6 ] Ni(OH) 2 has also attracted great interest as pseudocapacitive materials for supercapacitors due to its high theoretical specifi c pseudocapacitance of 2082 F g −1 (in a potential window of 0.5 V), environmental friendliness, and low cost. [ 7 ] In particular, Ni(OH) 2 in amorphous phase is expected to have better electrochemical effi ciency due to more grain boundaries and ion diffusion channels in the disordered structure compared to the crystalline phase. [ 7,8 ] The key issues of applying Ni(OH) 2 in practical supercapacitors lie in its low electrical conductivity and short cycle life. The electrical conductivity of Ni(OH) 2 is very low at around 10 −15 Ω −1 m −1 . [ 9 ] Thus, the redox reactions can only take place on its surface, and most of Ni(OH) 2 is inaccessible to electrolyte ions and remains as dead volume in supercapacitors. [ 10,11 ] Several approaches have been explored to address the issues caused by the low electrical conductivity of Ni(OH) 2 , including synthesis of porous structures, nanoparticles, thin fi lms, and nanosheets to expose more Ni(OH) 2 surfaces to electrolyte ions, [ 12,13 ] forming Ni(OH) 2 and carbon materials or conducting polymers hybrids to have imbedded conductive networks, [14][15][16][17][18] introducing other metal ions into Ni(OH) 2 to enhance its conductivity. [ 17,19,20 ] Even though these nanoscale engineering approaches can improve the electrical conductivity of Ni(OH) 2 , the constructed nanoscale structures often degrade and Ni ions dissolve into electrolytes after repeated charge/discharge cycles, which can result in short cycle life of supercapacitors. [ 5,13,14,[20][21][22] In this study, with the aim of constructing supercapacitors with both high energy density, good rate capability, and long cycle life, we have designed and synthesized a novel ternary hybrid electrode material comprising of multiwalled carbon nanotubes (MWCNTs), amorphous(amor)-Ni(OH) 2 and poly (3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) as high performance pseudocapacitive materials. Other than the commonly used crystalline Ni(OH) 2 , a thin layer of disordered amor-Ni(OH) 2 was deposited on conductive acidtreated MWCNTs by using a "coordinating etching and precipitating" method, which enabled effi cient redox reactions to take place mostly on the surface of Ni(OH) 2 . To prevent the dissolution of Ni ions into electrolytes and preserve the nanoscale structures amor-Ni(OH) 2 upon long charge/discharge cycles, a conductive polymer layer was further wrapped around the MWCNT/amor-Ni(OH) 2 . Such a unique hybrid architecture design results in Ni(OH) 2 pseudocapacitive materials with ult...

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“…One potential approach is to dope them with other elements. [13][14][15][16][17][18][19] The similar sizes of Ni and Co ion radii make it possible to dope nickel hydroxide-oxide with cobalt without causing serious lattice strain. The Co 2+ partially substitutes for Ni 2+ in the metal hydroxide-oxide, which may result in an increase of free holes in the valence band, and, therefore, enhancement of the p-type conductivity.…”

Section: Introductionmentioning

confidence: 99%

Co-doped Ni hydroxide and oxide nanosheet networks: laser-assisted synthesis, effective doping, and ultrahigh pseudocapacitor performance

Liang

et al. 2016

J. Mater. Chem. A

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Morphology control and impurity doping are two widely applied strategies to improve the electrochemical performance of nanomaterials. Herein, we report an environmentally friendly approach to obtain Co-doped Ni(OH) 2 nanosheet networks using a laser-induced cobalt colloid as a doping precursor followed by an aging treatment in a hybrid medium of nickel ions. The shape and specific surface area of the doped Ni(OH) 2 can be successfully adjusted by changing the concentration of sodium thiosulfate. Furthermore, a Co-doped Ni(OH) 2 nanosheet network was further converted into Co-doped NiO with its pristine morphology retained via facile thermal decomposition in air. The structure and electrochemical performance of the as-prepared samples are investigated with scanning and transmission electron microscopy, energy dispersive X-ray analysis, X-ray diffraction, Fourier transform infrared spectroscopy, the nitrogen adsorption-desorption isotherm technique, and electrochemical measurements. The Codoped Ni(OH) 2 electrode shows an ultrahigh specific capacitance of 1421 F g À1 at a current density of 6 A g À1 , and a good retention level of 76% after 1000 cycles, in sharp contrast with only a 47% retention level of the pure Ni(OH) 2 electrode at the same current density. In addition, the Co-doped NiO electrode exhibits a capacitance of 720 F g À1 at 6 A g À1 and 92% retention after 1000 cycles, which is also superior to the corresponding values of relevant pure NiO electrodes. The Co 2+ partially substitutes for Ni 2+ in the metal hydroxide and oxide, resulting in an increase of free holes in the valence band, and, therefore, enhancement of the p-type conductivity of Ni(OH) 2 and NiO. Moreover, such novel mesoporous nanosheet network structures are also able to enlarge the electrode-electrolyte contact area and shorten the path length for ion transport. The synergetic effect of these two results is responsible for the observed ultrahigh pseudocapacitor performance.

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Al and Co co-doped α-Ni(OH)2/graphene hybrid materials with high electrochemical performances for supercapacitors

Cited by 73 publications

References 43 publications

Nickel hydroxides and related materials: a review of their structures, synthesis and properties

Nickel hydroxides and related materials: a review of their structures, synthesis and properties

Ternary Hybrids of Amorphous Nickel Hydroxide–Carbon Nanotube‐Conducting Polymer for Supercapacitors with High Energy Density, Excellent Rate Capability, and Long Cycle Life

Co-doped Ni hydroxide and oxide nanosheet networks: laser-assisted synthesis, effective doping, and ultrahigh pseudocapacitor performance

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