Metal-Oxide Nanomaterials for Energy Application

A special issue of Nanomaterials (ISSN 2079-4991). This special issue belongs to the section "Energy and Catalysis".

Deadline for manuscript submissions: closed (31 May 2020) | Viewed by 22276

Special Issue Editors


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Guest Editor
Department of Applied Science and Technology, Politecnico di Torino, Torino, Italy
Interests: energy harvesting; zinc-oxide; piezoelectric materials; nanogenerators; nanotechnology; pressure sensors; nanomechanical systems

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Guest Editor
Politecnico di Torino, Dipartimento di Scienza Applicata e Tecnologia (DISAT), Corso Duca degli Abruzzi, 24, 10129 Torino, Italy
Interests: metal-oxide nanostructures; TiO2 nanotubes; graphene; supercapacitors; nanotechnology; dye-sensitized solar cells
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Special Issue Information

Dear Colleagues,

Great effort has been expended and assets spent to improve technologies for the conversion of renewable energy resources; day-by-day we face increasing energy consumption. Considering the request to reduce the dependence on conventional resources and develop a new energy landscape, renewable energy sources must be complemented by efficient energy storage systems characterized by robust technologies and at low associated costs.

In this context, metal-oxide nanostructures represent the most interesting candidates to overcome the actual limitations of several energy technologies. They have now been widely used in the design of energy saving and harvesting devices, such as mechanical nanogenerators, lithium-ion batteries, supercapacitors, fuel cells, photovoltaics, and even for hydrogen production by water photolysis.

This Special Issue of Nanomaterials will attempt to cover the most recent advances in metal oxide nanostructures, concerning, not only the synthesis and characterization, but especially focusing on their applications in energy harvesting, conversion and storage devices.

Dr. Stefano Stassi
Dr. Andrea Lamberti
Guest Editors

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Keywords

  • Advanced synthesis
  • Characterizations
  • Metal Oxide nanostructures
  • Energy harvesting
  • Mechanical Nanogenerators
  • Solar cells
  • Batteries
  • Supercapacitors
  • Hydrogen conversion
  • CO2 conversion

Published Papers (6 papers)

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Research

12 pages, 2927 KiB  
Article
Sol-Gel Processed TiO2 Nanotube Photoelectrodes for Dye-Sensitized Solar Cells with Enhanced Photovoltaic Performance
by Nikolai Tsvetkov, Liudmila Larina, Jeung Ku Kang and Oleg Shevaleevskiy
Nanomaterials 2020, 10(2), 296; https://doi.org/10.3390/nano10020296 - 10 Feb 2020
Cited by 32 | Viewed by 3112
Abstract
The performance of dye-sensitized solar cells (DSCs) critically depends on the efficiency of electron transport within the TiO2-dye-electrolyte interface. To improve the efficiency of the electron transfer the conventional structure of the working electrode (WE) based on TiO2 nanoparticles (NPs) [...] Read more.
The performance of dye-sensitized solar cells (DSCs) critically depends on the efficiency of electron transport within the TiO2-dye-electrolyte interface. To improve the efficiency of the electron transfer the conventional structure of the working electrode (WE) based on TiO2 nanoparticles (NPs) was replaced with TiO2 nanotubes (NTs). Sol-gel method was used to prepare undoped and Nb-doped TiO2 NPs and TiO2 NTs. The crystallinity and morphology of the WEs were characterized using XRD, SEM and TEM techniques. XPS and PL measurements revealed a higher concentration of oxygen-related defects at the surface of NPs-based electrodes compared to that based on NTs. Replacement of the conventional NPs-based TiO2 WE with alternative led to a 15% increase in power conversion efficiency (PCE) of the DSCs. The effect is attributed to the more efficient transfer of charge carriers in the NTs-based electrodes due to lower defect concentration. The suggestion was confirmed experimentally by electrical impedance spectroscopy measurements when we observed the higher recombination resistance at the TiO2 NTs-electrolyte interface compared to that at the TiO2 NPs-electrolyte interface. Moreover, Nb-doping of the TiO2 structures yields an additional 14% PCE increase. The application of Nb-doped TiO2 NTs as photo-electrode enables the fabrication of a DSC with an efficiency of 8.1%, which is 35% higher than that of a cell using a TiO2 NPs. Finally, NTs-based DSCs have demonstrated a 65% increase in the PCE value, when light intensity was decreased from 1000 to 10 W/m2 making such kind device be promising alternative indoor PV applications when the intensity of incident light is low. Full article
(This article belongs to the Special Issue Metal-Oxide Nanomaterials for Energy Application)
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13 pages, 5554 KiB  
Article
Amorphous Mo5O14-Type/Carbon Nanocomposite with Enhanced Electrochemical Capability for Lithium-Ion Batteries
by Ahmed M. Hashem, Ashraf E. Abdel-Ghany, Rasha S. El-Tawil, Sylvio Indris, Helmut Ehrenberg, Alain Mauger and Christian M. Julien
Nanomaterials 2020, 10(1), 8; https://doi.org/10.3390/nano10010008 - 18 Dec 2019
Cited by 7 | Viewed by 2701
Abstract
An amorphous MomO3m−1/carbon nanocomposite (m ≈ 5) is fabricated from a citrate–gel precursor heated at moderate temperature (500 °C) in inert (argon) atmosphere. The as-prepared Mo5O14-type/C material is compared to α-MoO3 synthesized from [...] Read more.
An amorphous MomO3m−1/carbon nanocomposite (m ≈ 5) is fabricated from a citrate–gel precursor heated at moderate temperature (500 °C) in inert (argon) atmosphere. The as-prepared Mo5O14-type/C material is compared to α-MoO3 synthesized from the same precursor in air. The morphology and microstructure of the as-prepared samples are characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Raman scattering (RS) spectroscopy. Thermal gravimetry and elemental analysis indicate the presence of 25.8 ± 0.2% of carbon in the composite. The SEM images show that Mo5O14 is immersed inside a honeycomb-like carbon matrix providing high surface area. The RS spectrum of Mo5O14/C demonstrates an oxygen deficiency in the molybdenum oxide and the presence of a partially graphitized carbon. Outstanding improvement in electrochemical performance is obtained for the Mo5O14 encapsulated by carbon in comparison with the carbon-free MoO3. Full article
(This article belongs to the Special Issue Metal-Oxide Nanomaterials for Energy Application)
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10 pages, 2106 KiB  
Article
Solid-State Solar Energy Conversion from WO3 Nano and Microstructures with Charge Transportation and Light-Scattering Characteristics
by Juyoung Moon, Woojun Shin, Jung Tae Park and Hongje Jang
Nanomaterials 2019, 9(12), 1797; https://doi.org/10.3390/nano9121797 - 17 Dec 2019
Cited by 14 | Viewed by 3146
Abstract
Solar energy conversion devices composed of highly crystalline gel polymers with disk-WO3 nanostructure and plate-WO3 microstructures (D-WO3 and P-WO3, respectively) exhibited higher power conversion efficiency than those with a gel electrolyte. In this study, D-WO3 and P-WO [...] Read more.
Solar energy conversion devices composed of highly crystalline gel polymers with disk-WO3 nanostructure and plate-WO3 microstructures (D-WO3 and P-WO3, respectively) exhibited higher power conversion efficiency than those with a gel electrolyte. In this study, D-WO3 and P-WO3 were prepared using a hydrothermal process and their structural and morphological features were investigated for application in solar energy conversion devices. The P-WO3 solid-state electrolyte significantly enhanced the cell performance owing to its charge transportation and light-scattering characteristics. The P-WO3 solid-state electrolyte showed a power conversion efficiency of 6.3%, which is higher than those of the gel (4.2%) and D-WO3 solid-state (5.5%) electrolytes. The electro-chemical impedance spectroscopy (EIS), intensity-modulated voltage spectroscopy (IMVS), diffuse reflectance, and incident photon-to-current conversion efficiency (IPCE) analysis results showed that the P-WO3 solid-state electrolyte showed improved charge transportation and light scattering, and hence enhanced the cell performance. Full article
(This article belongs to the Special Issue Metal-Oxide Nanomaterials for Energy Application)
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10 pages, 2696 KiB  
Communication
Facile Synthesis of Antimony Tungstate Nanosheets as Anodes for Lithium-Ion Batteries
by Yong Liu, Yue Wang, Fei Wang, Zhenxiao Lei, Wanhong Zhang, Kunming Pan, Jing Liu, Min Chen, Guangxin Wang, Fengzhang Ren and Shizhong Wei
Nanomaterials 2019, 9(12), 1689; https://doi.org/10.3390/nano9121689 - 25 Nov 2019
Cited by 28 | Viewed by 3812
Abstract
Lithium-ion batteries (LIBs) have been widely used in the fields of smart phones, electric vehicles, and smart grids. With its opened Aurivillius structure, tungstate antimony oxide (Sb2WO6, SWO), constituted of {Sb2O2}2n+ and {WO4 [...] Read more.
Lithium-ion batteries (LIBs) have been widely used in the fields of smart phones, electric vehicles, and smart grids. With its opened Aurivillius structure, tungstate antimony oxide (Sb2WO6, SWO), constituted of {Sb2O2}2n+ and {WO4}2n−, is rarely investigated as an anode for lithium-ion batteries. In this work, Sb2WO6 with nanosheets morphology was successfully synthesized using a simple microwave hydrothermal method and systematically studied as an anode for lithium-ion batteries. The optimal SWO (SWO-60) exhibits a high specific discharge capacity and good rate capability. The good electrochemical performance could be ascribed to mesoporous nanosheets morphology, which is favorable for the penetration of the electrolyte and charge transportation. The results show that this nanostructured SWO is a promising anode material for LIBs. Full article
(This article belongs to the Special Issue Metal-Oxide Nanomaterials for Energy Application)
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14 pages, 2831 KiB  
Article
Homogeneous Core/Shell NiMoO4@NiMoO4 and Activated Carbon for High Performance Asymmetric Supercapacitor
by Jia Yi Dong, Jin Cheng Xu, Kwun Nam Hui, Ye Yang, Shi Chen Su, Lin Li, Xi Tian Zhang, Kar Wei Ng, Shuang Peng Wang and Zi Kang Tang
Nanomaterials 2019, 9(7), 1033; https://doi.org/10.3390/nano9071033 - 19 Jul 2019
Cited by 11 | Viewed by 4351
Abstract
Here, we report the extraordinary electrochemical energy storage capability of NiMoO4@NiMoO4 homogeneous hierarchical nanosheet-on-nanowire arrays (SOWAs), synthesized on nickel substrate by a two-stage hydrothermal process. Comparatively speaking, the SOWAs electrode displays superior electrochemical performances over the pure NiMoO4 nanowire [...] Read more.
Here, we report the extraordinary electrochemical energy storage capability of NiMoO4@NiMoO4 homogeneous hierarchical nanosheet-on-nanowire arrays (SOWAs), synthesized on nickel substrate by a two-stage hydrothermal process. Comparatively speaking, the SOWAs electrode displays superior electrochemical performances over the pure NiMoO4 nanowire arrays. Such improvements can be ascribed to the characteristic homogeneous hierarchical structure, which not only effectively increases the active surface areas for fast charge transfer, but also reduces the electrode resistance significantly by eliminating the potential barrier at the nanowire/nanosheet junction, an issue usually seen in other reported heterogeneous architectures. We further evaluate the performances of the SOWAs by constructing an asymmetric hybrid supercapacitor (ASC) with the SOWAs and activated carbon (AC). The optimized ASC shows excellent electrochemical performances with 47.2 Wh/kg in energy density of 1.38 kW/kg at 0–1.2 V. Moreover, the specific capacity retention can be as high as 91.4% after 4000 cycles, illustrating the remarkable cycling stability of the NiMoO4@NiMoO4//AC ASC device. Our results show that this unique NiMoO4@NiMoO4 SOWA has great prospects for future energy storage applications. Full article
(This article belongs to the Special Issue Metal-Oxide Nanomaterials for Energy Application)
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13 pages, 5801 KiB  
Article
Synthesis of ZnxCd1-xSe@ZnO Hollow Spheres in Different Sizes for Quantum Dots Sensitized Solar Cells Application
by Libo Yu and Zhen Li
Nanomaterials 2019, 9(2), 132; https://doi.org/10.3390/nano9020132 - 22 Jan 2019
Cited by 23 | Viewed by 3962
Abstract
ZnxCd1-xSe@ZnO hollow spheres (HS) were successfully fabricated for application in quantum dot sensitized solar cells (QDSSCs) based on ZnO HS through the ion-exchange process. The sizes of the ZnxCd1-xSe@ZnO HS could be tuned from ~300 [...] Read more.
ZnxCd1-xSe@ZnO hollow spheres (HS) were successfully fabricated for application in quantum dot sensitized solar cells (QDSSCs) based on ZnO HS through the ion-exchange process. The sizes of the ZnxCd1-xSe@ZnO HS could be tuned from ~300 nm to ~800 nm using ZnO HS pre-synthesized by different sizes of carbonaceous spheres as templates. The photovoltaic performance of QDSSCs, especially the short-circuit current density (Jsc), experienced an obvious change when different sizes of ZnxCd1-xSe@ZnO HS are employed. The ZnxCd1-xSe@ZnO HS with an average size distribution of ~500 nm presented a better performance than the QDSSCs based on other sizes of ZnxCd1-xSe@ZnO HS. When using the mixture of ZnxCd1-xSe@ZnO HS with different sizes, the power conversion efficiency can be further improved. The size effect of the hollow spheres, light scattering, and composition gradient structure ZnxCd1-xSe@ZnO HS are responsible for the enhancement of the photovoltaic performance. Full article
(This article belongs to the Special Issue Metal-Oxide Nanomaterials for Energy Application)
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