Mesoporous Transition Metal Oxides for Supercapacitors

Wang, Yan; Guo, Jin; Wang, Tingfeng; Shao, Junfeng; Wang, Dong; Yang, Ying‐Wei

doi:10.3390/nano5041667

Cited by 352 publications

(150 citation statements)

References 85 publications

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“…However, its large-scale application is limited by the high cost and scarcity of Ru. 8 At present, the environmentally-benign transition metal oxides, such as MnO 2 , NiO, Co 3 O 4 and Fe 3 O 4 , have been found to exhibit excellent redox activity and are readily available; thus, a high energy storage capacity can be obtained at relatively low cost. 8 In contrast, the poor electrical conductivity and slow response of conducting polymer materials results in low power densities and poor stability.…”

Section: Introductionmentioning

confidence: 99%

Synthesis, structural and electrochemical properties of sodium nickel phosphate for energy storage devices

et al. 2016

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fElectrochemical energy production and storage at large scale and low cost, is a critical bottleneck in renewable energy systems. Oxides and lithium transition metal phosphates have been researched for over two decades and many technologies based on them exist. Much less work has been done investigating the use of sodium phosphates for energy storage. In this work, the synthesis of sodium nickel phosphate at different temperatures is performed and its performance evaluated for supercapacitor applications. The electronic properties of polycrystalline NaNiPO 4 polymorphs, triphylite and maricite, t-and m-NaNiPO 4 are calculated by means of first-principle calculations based on spin-polarized Density Functional Theory (DFT). The structure and morphology of the polymorphs were characterized and validated experimentally and it is shown that the sodium nickel phosphate (NaNiPO 4 ) exists in two different forms (triphylite and maricite), depending on the synthetic temperature (300-550°C). The as-prepared and triphylite forms of NaNiPO 4 vs. activated carbon in 2 M NaOH exhibit the maximum specific capacitance of 125 F g −1 and 85 F g −1 respectively, at 1 A g −1 ; both having excellent cycling stability with retention of 99% capacity up to 2000 cycles. The maricite form showed 70 F g −1 with a significant drop in capacity after just 50 cycles.These results reveal that the synthesized triphylite showed a high performance energy density of 44 Wh kg −1 which is attributed to the hierarchical structure of the porous NaNiPO 4 nanosheets. At a higher temperature (>400°C) the maricite form of NaNiPO 4 possesses a nanoplate-like (coarse and blocky) structure with a large skewing at the intermediate frequency that is not tolerant of cycling. Computed results for the sodium nickel phosphate polymorphs and the electrochemical experimental results are in good agreement.

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Section: Introductionmentioning

confidence: 99%

Synthesis, structural and electrochemical properties of sodium nickel phosphate for energy storage devices

et al. 2016

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“…3. Wand et al [8] have reported that quasi-rectangular shape of CV arises from unique electrochemical features of electrode active materials, such as reversible redox process, high thermal and chemical stability and pseudo capacitance. The CV curves with same shape at all scan rates also indicate a good capacitive performance of electrode.…”

Section: Resultsmentioning

confidence: 99%

La-Based Material for Energy Storage Applications

et al. 2017

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In this work, nanostructured La-based materials were produced by chemical precipitation method onto Cladosporium cladosporioides fungal hyphae in aqueous solution. Materials were annealed at various temperatures between 100• C-600• C. The morphological properties of the synthesized material were studied by transmission electron microscopy. The surface area for sample annealed at 360• C was determined to be 85.64 m 2 /g using Brunauer-Emmett-Teller method. The nitrogen adsorption and desorption isotherm displayed a typical type-IV isotherm. Electrochemical properties of produced material were studied using cyclic voltammetry, long term charge/discharge analysis and impedance spectroscopy in the 0.5 M Na2SO4 electrolyte. The obtained nanostructured porous electrode exhibits quasi-rectangular shaped cyclic voltammetry curves with a specific capacitance of 2190 F/g at a scan rate of 2 mV/s.

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“…Co is found in Figure 5D and the concentration of Ag falls below the detection limit in the same sample. Therefore, the uniform cube-structured particles are the result of Co [25,26].…”

Section: Aqueous Nanoparticle Emissionsmentioning

confidence: 99%

Environmental Emissions from Chemical Etching Synthesis of Silicon Nanotube for Lithium Ion Battery Applications

Guan

Wang

et al. 2018

JMMP

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Silicon nanotubes (SiNTs) have been researched as a promising anode material to replace graphite in next-generation lithium ion batteries. Chemical etching synthesis of SiNTs is a simple, controllable and scalable process for SiNT fabrication, but the environmental emissions are of grave concern. In this paper, the process emissions from chemical etching synthesis of SiNTs as anode for lithium ion batteries is studied through experimental techniques, considering the categories of aqueous wastes, gaseous emissions, aqueous nano-particle emissions, and gaseous aerosol emissions. The synthesized SiNTs are measured at 10 µm length and 1-2.2 µm diameter, and can maintain a specific capacity of over 800 mAh/g after 100 cycles in battery testing. In aqueous waste, the chemical compositions of all elements participating in the chemical etching are experimentally determined, with AgNO 3 and Co(NO 3 ) 2 identified as the major pollutants. The only gaseous emission generated from the chemical etching synthesis process is H 2 , with 0.0088 ± 0.0002 mol H 2 generated to produce 1.0 mg SiNTs. The aqueous nanoparticle sizes are found to be between 250 nm and 1540 nm. A large number of aerosol nanoparticle emissions of up to 2.96 × 10 7 particles/cm 3 are detected through in situ experimental measurement.

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Mesoporous Transition Metal Oxides for Supercapacitors

Cited by 352 publications

References 85 publications

Synthesis, structural and electrochemical properties of sodium nickel phosphate for energy storage devices

Synthesis, structural and electrochemical properties of sodium nickel phosphate for energy storage devices

La-Based Material for Energy Storage Applications

Environmental Emissions from Chemical Etching Synthesis of Silicon Nanotube for Lithium Ion Battery Applications

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