Nanostructured nickel oxide ultrafine nanoparticles: Synthesis, characterization, and supercapacitive behavior

Barani, Asghar; Aghazadeh, Mustafa; Ganjali, Mohammad Reza; Sabour, Behrouz; Barmi, Abbas-Ali Malek; Dalvand, Somayeh

doi:10.1016/j.mssp.2014.02.027

Cited by 44 publications

(9 citation statements)

References 29 publications

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“…The capacitances of NiO 30 -a/gr and NiO 70 -a/gr are similarly preserved during long cycle life (SI Appendix, Figs. S31C and S33C), thus implying that the rescaled particles do not suffer from degradation of the material over time (27,28). This stability of NiO-a/gr was further validated using an alternative reference electrode (SI Appendix, Fig.…”

Section: Absorption Due To the D-d Transitions (19) Characteristic Ofmentioning

confidence: 68%

Rescaling of metal oxide nanocrystals for energy storage having high capacitance and energy density with robust cycle life

Jeong

Choi

Cheng

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

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Nanocrystals are promising structures, but they are too large for achieving maximum energy storage performance. We show that rescaling 3-nm particles through lithiation followed by delithiation leads to high-performance energy storage by realizing high capacitance close to the theoretical capacitance available via ion-to-atom redox reactions. Reactive force-field (ReaxFF) molecular dynamics simulations support the conclusion that Li atoms react with nickel oxide nanocrystals (NiO-n) to form lithiated core-shell structures (Ni:Li 2 O), whereas subsequent delithiation causes Ni:Li 2 O to form atomic clusters of NiO-a. This is consistent with in situ X-ray photoelectron and optical spectroscopy results showing that Ni 2+ of the nanocrystal changes during lithiation-delithiation through Ni 0 and back to Ni 2+ . These processes are also demonstrated to provide a generic route to rescale another metal oxide. Furthermore, assembling NiO-a into the positive electrode of an asymmetric device enables extraction of full capacitance for a counter negative electrode, giving high energy density in addition to robust capacitance retention over 100,000 cycles.rescaled atomic clusters | metal oxide nanocrystals | energy storage | molecular dynamic simulation | in situ electrochemical spectroscopy T he most critical challenge in energy storage is maximizing capacitance along with high power density and long cycle life. High-power capacitors (1-4) are candidates to meet this challenge, and can be classified into two categories: (i) energy storage systems where charge is stored in electrochemical double layers (EDLs) (5, 6) and (ii) pseudocapacitors that store charge by redox reactions (7-14). Unfortunately, EDLs have low capacitance, whereas metal oxide pseudocapacitors lead to short cycle life. Furthermore, typical capacitors have low energy density (5, 10). In principle, the capacitances of metal oxide crystals can be fully obtained via ion-by-atom surface redox reactions. A capacitor that enables high capacitance with high energy density and long cycle life thus would represent a major breakthrough in energy storage.We synthesized metal oxide nanocrystals at a size of several nanometers on graphene, but found that rapid charging-discharging achieves only about 15% of their full capacitance. We hypothesized that reducing their sizes to the atomic clusters of subnanometer scales less than 1 nm, combined with conducting flexible graphene, would allow full redox reactions over entire constituents. Here we report that lithiation of 3-nm nickel oxide nanocrystals on graphene (NiO-n/gr) causes them to rescale down to subnanometer-scale Ni:Li 2 O-a/gr core-shell clusters and that subsequent delithiation of Ni:Li 2 O core-shell clusters leads to NiO (NiO-a/gr). We established the sequence as follows:NiO-n=gr → Ni : Li 2 O-a=gr → NiO-a=gr.We then verified this using a combination of experimental characterization with complementary reactive molecular dynamics.Moreover, we show that loading a positive electrode with NiO-a particles into an...

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Section: Absorption Due To the D-d Transitions (19) Characteristic Ofmentioning

confidence: 68%

Rescaling of metal oxide nanocrystals for energy storage having high capacitance and energy density with robust cycle life

Jeong

Choi

Cheng

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

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“…Their superior physico-chemical properties make them a promising candidate for advanced material applications. They can be used as electrode material for supercapacitors [16,17], active anode material for Li-ion batteries [18], as a catalyst for chemical and electrochemical reactions [19,20], an adsorbent for the removal of heavy metals from waste water [21,22], and as a component in gas sensors and electronic devices [23]. The preparation of NiO nanoparticles was studied by microwave method [8], solvothermal process [15], precipitation and subsequent calcination [18,19,21], sol-gel technique [20], and a hydrothermal method with subsequent calcination [24].…”

Section: Introductionmentioning

confidence: 99%

Simple Preparation of Ni and NiO Nanoparticles Using Raffinate Solution Originated from Spent NiMH Battery Recycling

Ebin

2018

J Inorg Organomet Polym

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Nickel (Ni) and nickel oxide (NiO) nanoparticles were produced by a combination of precipitation and reduction/calcination methods using the raffinate solution originated from laboratory scale spent NiMH recovery process. Ni recovery from the solution reached 99.8% by a simple precipitation step using baking soda. X-ray diffraction, FTIR spectroscopy, carbon analyzer and thermal gravimetric analysis techniques were used to characterize the precipitate. Metallic and oxide nanoparticles were obtained by hydrogen reduction and calcination under air atmosphere of the precipitate at 400 °C, respectively for 30-90 min residence times. The crystal structure, crystallite size, morphology, particle size and surface area of the samples, as well as carbon residue content in the particles were detected by particle characterization methods. The results indicate that spherical Ni nanoparticles have a crystallite size about 37 nm, and particle sizes of around 100 nm. The agglomeration of the nanoparticles reduces by increasing residence time. NiO nanoparticles have finer crystallite and particle sizes than the metallic samples produced at the same temperature and residence times. The results show that the combination of the simple methods presented can be an alternative process for producing advanced particles from spent NiMH batteries.

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“…These novel properties provide nanomaterials with a potential for technological applications such as magneto-recording, resistive switching, supercapacitors and biomedicine. [1][2][3][4][5][6] In particular, magnetic nanoparticles have been under scrutiny since the days of Néel 7 and Brown 8 who developed the theory of magnetization relaxation for non-interacting single domain particles. However, they show complex properties due to the occurrence of structural disorder, size distribution and random orientation of the magnetization vector, but majorly correlated to the interplay between finite size and surface effects.…”

Section: Introductionmentioning

confidence: 99%

Enhanced room temperature ferromagnetism in antiferromagnetic NiO nanoparticles

2015

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We report systematic investigations of structural, vibrational, resonance and magnetic properties of nanoscale NiO powders prepared by ball milling process under different milling speeds for 30 hours of milling. Structural properties revealed that both pure NiO and as-milled NiO powders exhibit face centered cubic structure, but average crystallite size decreases to around 11 nm along with significant increase in strain with increasing milling speed. Vibrational properties show the enhancement in the intensity of one-phonon longitudinal optical (LO) band and disappearance of two-magnon band due to size reduction. In addition, two-phonon LO band exhibits red shift due to size-induced phonon confinement effect and surface relaxation. Pure NiO powder exhibit antiferromagnetic nature, which transforms into induced ferromagnetic after size reduction. The average magnetization at room temperature increases with decreasing the crystallite size and a maximum moment of 0.016 μB/f.u. at 12 kOe applied field and coercivity of 170 Oe were obtained for 30 hours milled NiO powders at 600 rotation per minute milling speed. The change in the magnetic properties is also supported by the vibrational properties. Thermomagnetization measurements at high temperature reveal a well-defined magnetic phase transition at high temperature (TC) around 780 K due to induced ferromagnetic phase. Electron paramagnetic resonance (EPR) studies reveal a good agreement between the EPR results and magnetic properties. The observed results are described on the basis of crystallite size variation, defect density, large strain, oxidation/reduction of Ni and interaction between uncompensated surfaces and particle core with lattice expansion. The obtained results suggest that nanoscale NiO powders with high TC and moderate magnetic moment at room temperature with cubic structure would be useful to expedite for spintronic devices.

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Nanostructured nickel oxide ultrafine nanoparticles: Synthesis, characterization, and supercapacitive behavior

Cited by 44 publications

References 29 publications

Rescaling of metal oxide nanocrystals for energy storage having high capacitance and energy density with robust cycle life

Rescaling of metal oxide nanocrystals for energy storage having high capacitance and energy density with robust cycle life

Simple Preparation of Ni and NiO Nanoparticles Using Raffinate Solution Originated from Spent NiMH Battery Recycling

Enhanced room temperature ferromagnetism in antiferromagnetic NiO nanoparticles

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