Intense pulsed white light assisted fabrication of Co-CoOx core-shell nanoflakes on graphite felt for flexible hybrid supercapacitors

Park, Changyong; Hwang, Jeonguk; Hwang, Yeon Taek; Song, Chiho; Ahn, Suhyun; Kim, Kwang Ho; Ahn, Hye Shin

doi:10.1016/j.electacta.2017.06.087

Cited by 30 publications

(8 citation statements)

References 56 publications

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“…3e. The device exhibits an energy density of 0.14 and 0.09 Wh•cm −3 at 1.56 and 4.5 W•cm −3 , respectively, which is superior to the previous reports [33][34][35][36] . Cycling stability of the device is tested at a current density of 4 mA•cm −2 (Fig.…”

Section: Resultscontrasting

confidence: 66%

Asymmetric Hybrid Capacitor Based on NiCo2O4 Nanosheets Electrode

Tong¹,

Dai²,

Lü³

et al. 2020

Acta Phys Chim Sin

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The looming global energy crisis and ever-increasing energy demands have catalyzed the development of renewable energy storage systems. In this regard, supercapacitors (SCs) have attracted widespread attention because of their advantageous attributes such as high power density, excellent cycle stability, and environmental friendliness. However, SCs exhibit low energy density and it is important to optimize electrode materials to improve the overall performance of these devices. Among the various electrode materials available, spinel nickel cobaltate (NiCo2O4) is particularly interesting because of its excellent theoretical capacitance. Based on the understanding that the performances of the electrode materials strongly depend on their morphologies and structures, in this study, we successfully synthesized NiCo2O4 nanosheets on Ni foam via a simple hydrothermal route followed by calcination. The structures and morphologies of the as-synthesized products were characterized by X-ray diffraction, scanning electron microscopy, and Brunauer-Emmett-Teller (BET) surface area analysis, and the results showed that they were uniformly distributed on the Ni foam support. The surface chemical states of the elements in the samples were identified by X-ray photoelectron spectroscopy. The as-synthesized NiCo2O4 products were then tested as cathode materials for supercapacitors in a traditional three-electrode system. The electrochemical performances of the NiCo2O4 electrode materials were studied and the area capacitance was found to be 1.26 C•cm −2 at a current density of 1 mA•cm −2 . Furthermore, outstanding cycling stability with 97.6% retention of the initial discharge capacitance after 10000 cycles and excellent rate performance (67.5% capacitance retention with the current density from 1 to 14 mA•cm −2 ) were achieved. It was found that the Ni foam supporting the NiCo2O4 nanosheets increased the conductivity of the electrode materials. However, it is worth noting that the contribution of nickel foam to the areal capacitance of the electrode materials was almost zero during the charge and discharge processes. To further investigate the practical application of the assynthesized NiCo2O4 nanosheets-based electrode, a device was assembled with the as-prepared samples as the positive electrode and active carbon (AC) as the negative electrode. The assembled supercapacitor showed energy densities of 0.14 and 0.09 Wh•cm −3 at 1.56 and 4.5 W•cm −3 , respectively. Furthermore, it was able to maintain 95% of its initial specific capacitance after 10000 cycles. The excellent electrochemical performance of the NiCo2O4 nanosheets could be ascribed to their unique spatial structure composed of interconnected ultrathin nanosheets, which facilitated electron transportation and ion penetration, suggesting their potential applications as electrode materials for high performance supercapacitors. The present synthetic route can be extended to other ternary transition metal oxides/sulfides for future energy storage devices and systems.

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Section: Resultscontrasting

confidence: 66%

Asymmetric Hybrid Capacitor Based on NiCo2O4 Nanosheets Electrode

Tong¹,

Dai²,

Lü³

et al. 2020

Acta Phys Chim Sin

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“…The PVA/Na 2 SO 4 electrolyte gel was fabricated by adding Na 2 SO 4 (2.13 g) and PVA (3 g) into deionized water (50 mL), respectively and heating at 90°C for 2 h under constant stirring. The mass loading of the α-Fe 2 O 3 @C and MnO 2 was determined based on the charge balance principle, as shown in Formulas (3) and (4) [ 30 , 31 ]:

q , C , Δ V and m are the amount of the stored charge ( C ), the specific capacitance of the electrode (F g −1 ), the working voltage window ( V ), the mass loading of the active materials (g), respectively.…”

Section: Methodsmentioning

confidence: 99%

Porous α-Fe2O3@C Nanowire Arrays as Flexible Supercapacitors Electrode Materials with Excellent Electrochemical Performances

et al. 2018

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Porous α-Fe2O3 nanowire arrays coated with a layer of carbon shell have been prepared by a simple hydrothermal route. The as-synthesized products show an excellent electrochemical performance with high specific capacitance and good cycling life after 9000 cycles. A solid state asymmetric supercapacitor (ASC) with a 2 V operation voltage window has been assembled by porous α-Fe2O3/C nanowire arrays as the anode materials, and MnO2 nanosheets as the cathode materials, which gives rise to a maximum energy density of 30.625 Wh kg−1and a maximum power density of 5000 W kg−1 with an excellent cycling performance of 82% retention after 10,000 cycles.

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“…From the obtained C s values, the energy densities of ASC were calculated to be 45.8, 44.7, 42.2, 39.1, 37.7, 36.4, 34.7, 30.2, and 22.8 Wh·kg −1 recorded at average power densities of 208, 258, 512, 994, 1447, 1899, 2722, 4077, and 6227 W·kg −1 , respectively. Among these data, the maximum energy density (45.8 Wh·kg −1 at 208 W·kg −1 ) clearly surpassed that of similar ASCs reported (Figure 7g), such as Co 3 O 4 @Ni(OH) 2 //AC [34], Co–CoO x /graphite felt (GF)//AC [47], Co 3 O 4 //carbon aerogel [48], carbon quantum dots (CQDs)/NiCo 2 O 4 //AC [49], Co(OH) 2 / graphene nanosheet (GNS)//AC/carbon fiber paper (CFP) [50], C@Ni–Co LDH//C [38], Ni–Co OH–GH//GH [46], ZnCo 2 O 4 //AC [23], and Co(OH) 2 //AC [45]. In addition, a long-term repeated CD test at 1.5 mA·cm −2 was applied to evaluate the cycling stabilities of the as-assembled CoZn-MOH-45-110//AC ASC.…”

Section: Resultsmentioning

confidence: 86%

Electrochemically Stable Cobalt–Zinc Mixed Oxide/Hydroxide Hierarchical Porous Film Electrode for High-Performance Asymmetric Supercapacitor

Yang

Zhu

et al. 2019

Nanomaterials

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Construction of electrochemically stable positive materials is still a key challenge to accomplish high rate performance and long cycling life of asymmetric supercapacitors (ASCs). Herein, a novel cobalt–zinc mixed oxide/hydroxide (CoZn-MOH) hierarchical porous film electrode was facilely fabricated based on a cobalt–zinc-based metal–organic framework for excellent utilization in ASC. The as-constructed hierarchical porous film supported on conductive Ni foam possesses a rough surface and abundant macropores and mesopores, which allow fast electron transport, better exposure of electrochemically active sites, and facile electrolyte access and ion diffusion. Owing to these structural merits in collaboration, the CoZn-MOH electrode prepared with a zinc feeding ratio up to 45% at 110 min of heating time (CoZn-MOH-45-110) exhibited a high specific capacitance of 380.4 F·g−1, remarkable rate capability (83.6% retention after 20-fold current increase), and outstanding cycling performances (96.5% retention after 10,000 cycles), which exceed the performances of similar active electrodes. Moreover, an ASC based on this CoZn-MOH-45-110 electrode exhibited a high specific capacitance of 158.8 F·g−1, an impressive energy density of 45.8 Wh·kg−1, superior rate capability (83.1% retention after 50-fold current increase), and satisfactory cycling stability (87.9% capacitance retention after 12,000 cycles).

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Intense pulsed white light assisted fabrication of Co-CoOx core-shell nanoflakes on graphite felt for flexible hybrid supercapacitors

Cited by 30 publications

References 56 publications

Asymmetric Hybrid Capacitor Based on NiCo<sub>2</sub>O<sub>4</sub> Nanosheets Electrode

Asymmetric Hybrid Capacitor Based on NiCo<sub>2</sub>O<sub>4</sub> Nanosheets Electrode

Porous α-Fe2O3@C Nanowire Arrays as Flexible Supercapacitors Electrode Materials with Excellent Electrochemical Performances

Electrochemically Stable Cobalt–Zinc Mixed Oxide/Hydroxide Hierarchical Porous Film Electrode for High-Performance Asymmetric Supercapacitor

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