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16 pages, 4430 KiB

Open AccessEditor’s ChoiceArticle

Structural and Surfacial Modification of Carbon Nanofoam as an Interlayer for Electrochemically Stable Lithium-Sulfur Cells

by Yee-Jun Quay and Sheng-Heng Chung

Nanomaterials 2021, 11(12), 3342; https://doi.org/10.3390/nano11123342 - 9 Dec 2021

Cited by 12 | Viewed by 3258

Abstract

Electrochemical lithium-sulfur batteries engage the attention of researchers due to their high-capacity sulfur cathodes, which meet the increasing energy-density needs of next-generation energy-storage systems. We present here the design, modification, and investigation of a carbon nanofoam as the interlayer in a lithium-sulfur cell to enable its high-loading sulfur cathode to attain high electrochemical utilization, efficiency, and stability. The carbon-nanofoam interlayer features a porous and tortuous carbon network that accelerates the charge transfer while decelerating the polysulfide diffusion. The improved cell demonstrates a high electrochemical utilization of over 80% and an enhanced stability of 200 cycles. With such a high-performance cell configuration, we investigate how the battery chemistry is affected by an additional polysulfide-trapping MoS₂ layer and an additional electron-transferring graphene layer on the interlayer. Our results confirm that the cell-configuration modification brings major benefits to the development of a high-loading sulfur cathode for excellent electrochemical performances. We further demonstrate a high-loading cathode with the carbon-nanofoam interlayer, which attains a high sulfur loading of 8 mg cm⁻², an excellent areal capacity of 8.7 mAh cm⁻², and a superior energy density of 18.7 mWh cm⁻² at a low electrolyte-to-sulfur ratio of 10 µL mg⁻¹. Full article

(This article belongs to the Special Issue State-of-the-Art Nanomaterials for Energy Storage/Conversion and Electrocatalysis in Taiwan)

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12 pages, 3624 KiB

Open AccessArticle

Advanced Current Collectors with Carbon Nanofoams for Electrochemically Stable Lithium—Sulfur Cells

by Shu-Yu Chen and Sheng-Heng Chung

Nanomaterials 2021, 11(8), 2083; https://doi.org/10.3390/nano11082083 - 17 Aug 2021

Cited by 15 | Viewed by 3121

Abstract

An inexpensive sulfur cathode with the highest possible charge storage capacity is attractive for the design of lithium-ion batteries with a high energy density and low cost. To promote existing lithium–sulfur battery technologies in the current energy storage market, it is critical to increase the electrochemical stability of the conversion-type sulfur cathode. Here, we present the adoption of a carbon nanofoam as an advanced current collector for the lithium–sulfur battery cathode. The carbon nanofoam has a conductive and tortuous network, which improves the conductivity of the sulfur cathode and reduces the loss of active material. The carbon nanofoam cathode thus enables the development of a high-loading sulfur cathode (4.8 mg cm⁻²) with a high discharge capacity that approaches 500 mA·h g⁻¹ at the C/10 rate and an excellent cycle stability that achieves 90% capacity retention over 100 cycles. After adopting such an optimal cathode configuration, we superficially coat the carbon nanofoam with graphene and molybdenum disulfide (MoS₂) to amplify the fast charge transfer and strong polysulfide-trapping capabilities, respectively. The highest charge storage capacity realized by the graphene-coated carbon nanofoam is 672 mA·h g⁻¹ at the C/10 rate. The MoS₂-coated carbon nanofoam features high electrochemical utilization attaining the high discharge capacity of 633 mA·h g⁻¹ at the C/10 rate and stable cyclability featuring a capacity retention approaching 90%. Full article

(This article belongs to the Special Issue Emerging Nanomaterials for Lithium-Sulfur Batteries and Beyond II)

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12 pages, 2110 KiB

Open AccessArticle

Super Hydrophilic Activated Carbon Decorated Nanopolymer Foam for Scalable, Energy Efficient Photothermal Steam Generation, as an Effective Desalination System

by Naila Arshad, Iftikhar Ahmed, Muhammad Sultan Irshad, Hong Rong Li, Xianbao Wang, Shafiq Ahmad, Mohamed Sharaf, Muhammad Firdausi, Mazen Zaindin and Muhammad Atif

Nanomaterials 2020, 10(12), 2510; https://doi.org/10.3390/nano10122510 - 14 Dec 2020

Cited by 27 | Viewed by 4286

Abstract

Clean water scarcity is still an intense, prolonged global issue that needs to be resolved urgently. The solar steam generation has shown great potential with a high energy conversion efficiency for clean water production from seawater and wastewater. However, the high evaporation rate of water cannot be preserved due to the inevitable fouling of solar absorbers. Herein, a self-floatable and super hydrophilic solar-driven steam generator composed of activated carbon coated melamine foam (ACM). The deposited ACM photothermal layer exhibits outstanding solar absorption (92%) and an efficient evaporation rate of 1.27 kg m⁻² h⁻¹, along with excellent photothermal conversion efficiency (80%) as compared to commercially available primitive solar stills. The open porous assembly of melamine foam equipped with 80% flexibility (0.8 MPa) enabled smooth water transport and sustain heat accumulation within the matrix. The thermal insulation of ACM is 10 times greater than pure water. Moreover, open porous assembly of designed solar-powered steam generator rejects salt ions as well as volatile organic compounds efficiently. The low-cost and facile fabrication of photothermal based water production presents a potential solution to single step drinking water supply from various resources of the sea, the lakes and mixtures of emulsified oil and industrial wastewater. Full article

(This article belongs to the Section Environmental Nanoscience and Nanotechnology)

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14 pages, 1072 KiB

Open AccessArticle

Diamond-Like Carbon Nanofoam from Low-Temperature Hydrothermal Carbonization of a Sucrose/Naphthalene Precursor Solution

by Natalie Frese, Shelby Taylor Mitchell, Amanda Bowers, Armin Gölzhäuser and Klaus Sattler

C 2017, 3(3), 23; https://doi.org/10.3390/c3030023 - 6 Jul 2017

Cited by 11 | Viewed by 8151

Abstract

Unusual structure of low-density carbon nanofoam, different from the commonly observed micropearl morphology, was obtained by hydrothermal carbonization (HTC) of a sucrose solution where a specific small amount of naphthalene had been added. Helium-ion microscopy (HIM) was used to obtain images of the foam yielding micron-sized, but non-spherical particles as structural units with a smooth foam surface. Raman spectroscopy shows a predominant sp² peak, which results from the graphitic internal structure. A strong sp³ peak is seen in X-ray photoelectron spectroscopy (XPS). Electrons in XPS are emitted from the near surface region which implies that the graphitic microparticles have a diamond-like foam surface layer. The occurrence of separated sp² and sp³ regions is uncommon for carbon nanofoams and reveals an interesting bulk-surface structure of the compositional units. Full article

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