High energy density asymmetric supercapacitors with a nickel oxide nanoflake cathode and a 3D reduced graphene oxide anode

Luan, Feng; Wang, Gongming; Ling, Yichuan; Lu, Xihong; Wang, Hanyu; Tong, Yexiang; Liu, Xiao Xia; Li, Yat

doi:10.1039/c3nr02710d

Cited by 262 publications

(137 citation statements)

References 29 publications

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“…The relatively symmetric shapes of these curves indicate the ideal capacitive characteristics and rapid charge/discharge properties of the ANF//RGO-ASC device. As shown in Figure 5d, the ANF//RGO-ASC device achieved the highest volumetric capacitance of 3.42 F cm À3 at 6 mA cm À2 , which is substantially higher than the values reported recently for other ASCs, such as an NiO//RGO-ASC device (1.37 F cm À3 at 1 mA cm À2 ), 39 an MnO 2 /RGO//RGO-ASC device (1.60 F cm À3 at 4 mA cm À2 ), 16 a VO x //VN-ASC device (1.35 F cm À3 at 0.5 mA cm À2 ), 9 a TiO 2 @MnO 2 //TiO 2 @C-ASC device (0.67 F cm À3 at 0.5 mA cm À2 ) 28 and a ZnO@MnO 2 //RGO-ASC device (0.52 F cm À3 at 0.5 mA cm À2 ). 24 In addition, when the current density increased from 6 to 20 mA cm À2 , the ANF//RGO-ASC device retained 58% of its capacitance, demonstrating its good rate capability, and more than 95% of the coulombic efficiency was retained at any current density.…”

Section: Figure 1 (A) Schematic Diagram Illustrating the Activation Pmentioning

confidence: 55%

Scalable self-growth of Ni@NiO core-shell electrode with ultrahigh capacitance and super-long cyclic stability for supercapacitors

et al. 2014

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Three-dimensional (3D) electrodes have been demonstrated to be promising candidates for high-performance supercapacitors because of their unique architectures and outstanding electrochemical properties. However, the fabrication process for current 3D electrodes is not scalable. Herein, a novel and cost-effective activation process has been developed to macroscopically produce 3D porous Ni@NiO core-shell electrodes with enhanced electrochemical properties. The porous Ni@NiO core-shell electrode obtained by activated commercial Ni foam (NF) in a 3 M HCl solution yields an ultrahigh areal capacitance of 2.0 F cm À2 at a high current density of 8 mA cm À2 , which is substantially higher than that of most reported 3D NF-based electrodes. Moreover, the activated NF (ANF) electrode exhibited super-long cycling stability. Owing to the increased accessible surface area and continual formation of electrochemically active NiO during cycling, the areal capacitance of the ANF electrode did not exhibit any decay and instead increased from 0.47 to 1.27 F cm À2 after 100 000 cycles at 100 mV s À1 . This is the best cycling stability achieved by a 3D NF-based electrode. Additionally, a high-performance asymmetrical supercapacitor (ASC) device based on the as-prepared ANF cathode and a reduced graphene oxide (RGO) anode was also prepared. The ANF//RGO-ASC device was able to deliver a maximum energy density of 1.06 mWh cm À3 and a maximum power density of 0.42 W cm À3 .

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Section: Figure 1 (A) Schematic Diagram Illustrating the Activation Pmentioning

confidence: 55%

Scalable self-growth of Ni@NiO core-shell electrode with ultrahigh capacitance and super-long cyclic stability for supercapacitors

et al. 2014

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“…A capacitance of 118 F g NiO-a/grjjAC −1 at 1.5 A g −1 , close to the ultimate capacitance of AC (122 F g −1 ), was obtained. Both full-cell devices present excellent stability with almost 100% capacity retention over 100,000 cycles at a fast current density of 12 A g −1 , compared with short cycle life using other metal oxide capacitors (30)(31)(32). These results suggest that the high-performance pseudocapacitive properties of the NiO-a/gr electrode would allow high capacitance and stable charge retention in a fullcell configuration with other promising counter electrodes.…”

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

confidence: 61%

“…5F and SI Appendix, section S13). These energy and power densities are excellent compared with those of nickel-oxide-based capacitors (31,32), nickel-hydroxide-based capacitors (33)(34)(35), and manganese-oxide-based asymmetric capacitor devices (36,37).…”

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

confidence: 62%

“…(E) Cycling performance of asymmetric full-cell devices based on NiO-a/gr and NG electrodes in addition to that using NiO-a/gr and NG electrodes at a current density of 12 A g −1 . (F) Ragone plot of capacitors using NiO-a/gr and NG electrodes, NiO-a/gr and AC electrodes, and other data reported in the literature (31)(32)(33)(34)(35)(36)(37). All data in this figure are based on the asymmetric capacitor with the total mass of both electrodes.…”

Section: Methodsmentioning

confidence: 99%

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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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“…Carbon materials with large specific surface areas and excellent conductivity, such as activated carbon [39,40], carbon nanofibers [41,42], mesoporous carbon [43,44], carbon nanotubes (CNTs) [45,46], graphene [47,48], and carbide-derived carbon [49,50], have been widely employed in EDLCs. While in PCs, composite materials composed of carbon nanomaterials together with electrically conductive polymers (e.g., polyaniline (PANI) [51][52][53][54], polypyrrole (PPy) [55][56][57][58], and poly[3,4-ethylenedioxythiophene] (PEDOT) [59]) or transition metal oxides (e.g., MnO 2 [60,61], NiO [62,63], RuO 2 [64,65], VO x [66][67][68], and TiO 2 [69,70] ) have been widely used for the electrodes. PCs, utilizing redox reactions to store/release energy, possess much higher energy densities with compromised power densities [71].…”

Section: Introductionmentioning

confidence: 99%

Recent advances and challenges of stretchable supercapacitors based on carbon materials

Zhang

Lin

et al. 2016

Sci. China Mater.

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Stretchable energy storage devices are essential for the development of stretchable electronics that can maintain their electronic performance while sustain large mechanical strain. In this context, stretchable supercapacitors (SSCs) are regarded as one of the most promising power supply in stretchable electronic devices due to their high power densities, fast charge-discharge capability, and modest energy densities. Carbon materials, including carbon nanotubes, graphene, and mesoporous carbon, hold promise as electrode materials for SSCs for their large surface area, excellent electrical, mechanical, and electrochemical properties. Much effort has been devoted to developing stretchable, carbon-based SSCs with different structure/performance characteristics, including conventional planar/textile, wearable fiber-shaped, transparent, and solid-state devices with aesthetic appeal. This review summarizes recent advances towards the development of carbon-based SSCs. Challenges and important directions in this emerging field are also discussed.

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High energy density asymmetric supercapacitors with a nickel oxide nanoflake cathode and a 3D reduced graphene oxide anode

Cited by 262 publications

References 29 publications

Scalable self-growth of Ni@NiO core-shell electrode with ultrahigh capacitance and super-long cyclic stability for supercapacitors

Scalable self-growth of Ni@NiO core-shell electrode with ultrahigh capacitance and super-long cyclic stability for supercapacitors

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

Recent advances and challenges of stretchable supercapacitors based on carbon materials

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