Nanoenergy Advances

14 pages, 7186 KiB

Open AccessFeature PaperArticle

Doped-Cellulose Acetate Membranes as Friction Layers for Triboelectric Nanogenerators: The Influence of Roughness Degree and Surface Potential on Electrical Performance

by Iuri Custodio Montes Candido, Andre Luiz Freire, Carlos Alberto Rodrigues Costa and Helinando Pequeno de Oliveira

Nanoenergy Adv. 2024, 4(2), 196-208; https://doi.org/10.3390/nanoenergyadv4020012 - 20 Jun 2024

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Abstract

The development of more efficient friction layers for triboelectric nanogenerators is a complex task, requiring a careful balance of various material properties such as morphology, surface roughness, dielectric constant, and surface potential. In this study, we thoroughly investigated the use of cellulose acetate modified with different concentrations of zinc oxide and titanium dioxide to enhance energy harvesting for the TENG. The results indicate that the roughness degree is influenced by the homogeneous degree/aggregation level of doping agents in cellulose acetate membranes, leading to the best performance of open circuit voltage of 282.8 V, short-circuit current of 3.42 µA, and power density of 60 µW/cm² for ZnO-doped cellulose acetate membranes. Full article

(This article belongs to the Special Issue Celebrating the 18th Anniversary of the Invention of the First Nanogenerators)

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22 pages, 5606 KiB

Open AccessArticle

Influence of Water on Aging Phenomena of Calendric Stored and Cycled Li-Ion Batteries

by Gudrun Wilhelm, Ute Golla-Schindler, Katharina Wöhrl, Christian Geisbauer, Graham Cooke, Timo Bernthaler, Hans-Georg Schweiger and Gerhard Schneider

Nanoenergy Adv. 2024, 4(2), 174-195; https://doi.org/10.3390/nanoenergyadv4020011 - 19 Jun 2024

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Abstract

We examine the impact of water (160 ± 41 ppm of reference) on the anode, cathode, separator and electrolyte in two aging scenarios: calendric aging (60 °C, 80 days, charged state), resulting in a triggered current interrupt device (CID), and cycling 1680 times (charge/discharge with 1C, 2.75–4.2 V, 20 ± 2 °C), resulting in 24.5% residual capacity. We applied computer tomography (CT), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and secondary ion mass spectrometry (SIMS) to understand the capacity loss. The aged NMC/LCO–graphite cells were compared to a reference cell in pristine state. Both aging scenarios showed (a) thick depositions on the anode and cathode consisting mainly of oxygen, fluorine and phosphorous, (b) reduced separator pore sizes, (c) the deposition of Mn, Co and Ni on top of the anode and (d) the decomposition of the conductive salt LiPF₆ accompanied by HF formation and a loss of active lithium. Calendric aging consumes the water content and additionally leads to (e) the decomposition of the organic solvent followed by CO₂ gas formation. Cyclic aging increases the water content and additionally results in (f) the consumption of the additive fluoroethylene carbonate (FEC). These findings show how water affects aging phenomena and results in a capacity decrease in the cell. Full article

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18 pages, 10597 KiB

Open AccessFeature PaperReview

Recent Progress in Blue Energy Harvesting Based on Triboelectric Nanogenerators

by Long Liu, Tong Hu, Xinmao Zhao and Chengkuo Lee

Nanoenergy Adv. 2024, 4(2), 156-173; https://doi.org/10.3390/nanoenergyadv4020010 - 23 May 2024

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Abstract

This paper reviews and summarizes recent progress in blue energy harvesting based on a triboelectric nanogenerator (TENG). This review covers TENG-based blue energy harvesters (BEHs) with different inertial units in spherical structures, derivative spherical structures, buoy structures, and liquid–solid contact structures. These research works have paved the way for TENG-based BEHs working under low-frequency waves and harvesting wave energy efficiently. The TENG-based BEH unit design and networking strategy are also discussed, along with highlighted research works. The advantages and disadvantages of different TENG structures with other inertial units are explored and discussed. Meanwhile, power management strategies are also mentioned in this paper. Thus, as a promising blue energy harvesting technology, the TENG is expected to significantly contribute to developing low-cost, lightweight, and high-performance BEHs supporting more frequent marine activities. Full article

(This article belongs to the Special Issue Celebrating the 18th Anniversary of the Invention of the First Nanogenerators)

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10 pages, 1287 KiB

Open AccessArticle

Modeling Particle-Doped Materials for Performance Improvement of Contact-Separation Triboelectric Nanogenerators

by Carlos Callaty, Isabel Gonçalves, Cátia Rodrigues and João Ventura

Nanoenergy Adv. 2024, 4(2), 147-155; https://doi.org/10.3390/nanoenergyadv4020009 - 30 Apr 2024

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Abstract

Triboelectric nanogenerators (TENGs) are an attractive energy harvesting technology due to their high efficiency and vast applications in self-powered sensors. In this work, dielectric–dielectric contact-separation TENGs were modeled with time-dependent finite element simulations with the objective of improving TENG’s performance by enhancing the [...] Read more.

ε_{r}

).To achieve this, the chosen material (PDMS,

ε_{r} = 2.75

) was doped with SrTiO₃ (

ε_{r}

= 300) particles. The open-circuit voltage (

V_{O C}

) and short-circuit current (

I_{S C}

) remained constant as

ϵ_{r}

increased, as predicted by existent models, but in contradiction with available experimental data. Thus, we introduced a charge correction model relating

ϵ_{r}

and surface charge density, allowing us to observe an increase in TENG performance output (

V_{O C}

and

I_{S C}

). This work shows that finite element simulations are suitable for better understanding and optimizing TENGs’ performance. Full article

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14 pages, 7100 KiB

Open AccessArticle

Surface Charge: An Advantage for the Piezoelectric Properties of GaN Nanowires

by Tanbir Kaur Sodhi, Pascal Chrétien, Quang Chieu Bui, Amaury Chevillard, Laurent Travers, Martina Morassi, Maria Tchernycheva, Frédéric Houzé and Noelle Gogneau

Nanoenergy Adv. 2024, 4(2), 133-146; https://doi.org/10.3390/nanoenergyadv4020008 - 2 Apr 2024

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Abstract

The optimization of the new generation of piezoelectric nanogenerators based on 1D nanostructures requires a fundamental understanding of the different physical mechanisms at play, especially those that become predominant at the nanoscale regime. One such phenomenon is the surface charge effect (SCE), which is very pronounced in GaN NWs with sub-100 nm diameters. With an advanced nano-characterization tool derived from AFM, the influence of SCE on the piezo generation capacity of GaN NWs is investigated by modifying their immediate environment. As-grown GaN NWs are analysed and compared to their post-treated counterparts featuring an Al₂O₃ shell. We establish that the output voltages systematically decrease by the Al₂O₃ shell. This phenomenon is directly related to the decrease of the surface trap density in the presence of Al₂O₃ and the corresponding reduction of the surface Fermi level pinning. This leads to a stronger screening of the piezoelectric charges by the free carriers. These experimental results demonstrate and confirm that the piezo-conversion capacity of GaN NWs is favoured by the presence of the surface charges. Full article

(This article belongs to the Special Issue Fabrication and Characterization of Materials for Nanoenergy)

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Nanoenergy Adv., Volume 4, Issue 2 (June 2024) – 5 articles

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