Exploring the Versatile Surface Chemistry of Silica Aerogels for Multipurpose Application

MRS Advances ◽  
2017 ◽  
Vol 2 (57) ◽  
pp. 3511-3519 ◽  
Author(s):  
Luisa Durães ◽  
Hajar Maleki ◽  
João P. Vareda ◽  
Alyne Lamy-Mendes ◽  
António Portugal
Keyword(s):  
Heavy Metals ◽  
Surface Chemistry ◽  
Thermal Insulation ◽  
High Performance ◽  
Rate Capability ◽  
Silica Aerogels ◽  
Magnetic Feature ◽  
High Porosity ◽  
Silica Network ◽  
First Case

ABSTRACTSilica aerogels are unique lightweight, nanostructured materials with extremely high porosity (usually above 90%), making them particularly attractive for thermal insulation, although their mechanical fragility still requires strategies of reinforcement that may compromise some of their most appealing properties. The use of silica aerogels still needs to be matured for a broad range of other high-performance applications, and even improved for insulation application. This can be achieved by intensely exploring their surface chemistry versatility, by relying on the enormous variety of silane precursors and chemical routes that can be used. In this work, we present two examples of using reactive moieties in the silane precursors for the preparation of silica aerogels for multipurpose application. In the first case, an acrylate containing silane (3-(trimethoxysilyl)propyl methacrylate) is used along with tetramethyl orthosilicate to produce an organically-modified silica network, which could be reinforced by adding 1,6-bis(trimethoxysilyl)hexane or 1,4-bis(triethoxysilyl)-benzene as spacers and tris[2-(acryloyloxy)ethyl] isocyanurate as cross-linker. These hybrid aerogels have shown an interesting combination of thermal insulation and mechanical properties. Moreover, they could be chemically doped with silica-functionalized magnetite nanoparticles imparting magnetic behaviour to the aerogels but also improving their thermal insulation performance and mechanical strength. Their magnetic feature can be useful for several applications including magnetic separation and drug delivery. As a second example, amine and thiol-functionalized aerogels were used as adsorbents to capture heavy metals from wastewater by complexation, and the preparation of these materials could be accomplished using a combination of silanes, including hydrophobic moieties for a compromise to ensure material stability and good adsorption capacities. Removal percentages of heavy metals reaching 90% were found for metal concentrations of environmental relevance. The amine functionality in aerogels is also useful for other purposes, for example to improve the rate capability of silica aerogels to remove carbon dioxide from gaseous streams or environments.

scholarly journals Continuous, Strong, Porous Silk Firoin-Based Aerogel Fibers toward Textile Thermal Insulation

Polymers ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1899 ◽  
Author(s):  
Haiwei Yang ◽  
Zongqian Wang ◽  
Zhi Liu ◽  
Huan Cheng ◽  
Changlong Li
Keyword(s):  
Heat Transfer ◽  
Thermal Insulation ◽  
Hollow Fiber ◽  
High Performance ◽  
Large Scale ◽  
Low Density ◽  
Potential Candidate ◽  
Scale Production ◽  
Insulation Material ◽  
High Porosity

Aerogel fiber, with the characteristics of ultra-low density, ultra-high porosity, and high specific surface area, is the most potential candidate for manufacturing wearable thermal insulation material. However, aerogel fibers generally show weak mechanical properties and complex preparation processes. Herein, through firstly preparing a cellulose acetate/polyacrylic acid (CA/PAA) hollow fiber using coaxial wet-spinning followed by injecting the silk fibroin (SF) solution into the hollow fiber, the CA/PAA-wrapped SF aerogel fibers toward textile thermal insulation were successfully constructed after freeze-drying. The sheath (CA/PAA hollow fiber) possesses a multiscale porous structure, including micropores (11.37 ± 4.01 μm), sub-micron pores (217.47 ± 46.16 nm), as well as nanopores on the inner (44.00 ± 21.65 nm) and outer (36.43 ± 17.55 nm) surfaces, which is crucial to the formation of a SF aerogel core. Furthermore, the porous CA/PAA-wrapped SF aerogel fibers have many advantages, such as low density (0.21 g/cm3), high porosity (86%), high strength at break (2.6 ± 0.4 MPa), as well as potential continuous and large-scale production. The delicate structure of multiscale porous sheath and ultra-low-density SF aerogel core synergistically inhibit air circulation and limit convective heat transfer. Meanwhile, the high porosity of aerogel fibers weakens heat transfer and the SF aerogel cellular walls prevent infrared radiation. The results show that the mat composed of these aerogel fibers exhibits excellent thermal insulating properties with a wide working temperature from −20 to 100 °C. Therefore, this SF-based aerogel fiber can be considered as a practical option for high performance thermal insulation.

scholarly journals Preparation and Performance of Porous Carbon Nanocomposite from Renewable Phenolic Resin and Halloysite Nanotube

Nanomaterials ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1703
Author(s):  
Xiaomeng Yang ◽  
Xiaorui Zeng ◽  
Guihong Han ◽  
Dong Sui ◽  
Xiangyu Song ◽  
...  
Keyword(s):  
High Performance ◽  
Phenolic Resin ◽  
Electrode Materials ◽  
Rate Capability ◽  
Total Pore Volume ◽  
High Energy ◽  
High Energy Density ◽  
Cycle Performance ◽  
High Porosity ◽  
Halloysite Nanotube

The growing demand for high performance from supercapacitors has inspired the development of porous nanocomposites using renewable and naturally available materials. In this work, a formaldehyde-free phenolic resin using monosaccharide-based furfural was synthesized to act as the carbon precursor. One dimensional halloysite nanotube (HNT) with high porosity and excellent cation/anion exchange capacity was mixed with the phenol-furfural resin to fabricate carbonaceous nanocomposite HNT/C. Their structure and porosity were characterized. The effects of the halloysite nanotube amount and carbonization temperature on the electrochemical properties of HNT/C were explored. HNT/C exhibited rich porosity, involving a large specific surface area 253 m2·g−1 with a total pore volume of 0.27 cm3·g−1. The electrochemical performance of HNT/C was characterized in the three-electrode system and showed enhanced specific capacitance of 146 F·g−1 at 0.2 A g−1 (68 F·g−1 for pristine carbon) in electrolyte (6 mol·L−1 KOH) and a good rate capability of 62% at 3 A g−1. It also displayed excellent cycle performance with capacitance retention of 98.5% after 500 cycles. The symmetric supercapacitors with HNT/C-1:1.5-800 electrodes were fabricated, exhibiting a high energy density of 20.28 Wh·Kg−1 at a power density of 100 W·Kg−1 in 1 M Na2SO4 electrolyte. The present work provides a feasible method for preparing composite electrode materials with a porous structure from renewable phenol-furfural resin and HNT. The excellent supercapacitance highlights the potential applications of HNT/C in energy storage.

scholarly journals 3-Dimensional Porous Carbon with High Nitrogen Content Obtained from Longan Shell and Its Excellent Performance for Aqueous and All-Solid-State Supercapacitors

Nanomaterials ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 808 ◽  
Author(s):  
Yuhao Liu ◽  
Xiaoxiao Qu ◽  
Guangxu Huang ◽  
Baolin Xing ◽  
Fengmei Zhang ◽  
...  
Keyword(s):  
Solid State ◽  
Porous Carbon ◽  
High Performance ◽  
Electrode Materials ◽  
Rate Capability ◽  
Value Added ◽  
Koh Activation ◽  
Electrochemical Performances ◽  
High Porosity ◽  
3 Dimensional

Three-dimensional porous carbon is considered as an ideal electrode material for supercapacitors (SCs) applications owing to its good conductivity, developed pore structure, and excellent connectivity. Herein, using longan shell as precursor, 3-dimensional porous carbon with abundant and interconnected pores and moderate heteroatoms were obtained via simple carbonization and potassium hydroxide (KOH) activation treatment. The electrochemical performances of obtained 3-dimensional porous carbon were investigated as electrode materials in symmetric SCs with aqueous and solid electrolytes. The optimized material that is named after longan shell 3-dimensional porous carbon 800 (LSPC800) possesses high porosity (1.644 cm3 g−1) and N content (1.14 at %). In the three-electrode measurement, the LSPC800 displays an excellent capacitance value of 359 F g−1. Besides, the LSPC800 also achieves splendid specific capacitance (254 F g−1) in the two electrode system, while the fabricated SC employing 1 M Li2SO4 as electrolyte acquires ultrahigh power density (15930.38 W kg−1). Most importantly, LSPC800 electrodes are further applied into the SC adopting the KOH/polyvinyl alcohol (PVA) gel electrolyte, which reaches up to an outstanding capacitance of 313 F g−1 at 0.5 A g−1. In addition, for the all-solid-state SC, its rate capability at 50 A g−1 is 72.73% and retention at the 10,000th run is 93.64%. Evidently, this work is of great significance to the simple fabrication of 3-dimensional porous carbon and further opens up a way of improving the value-added utilization of biomass materials, as well as proving that the biomass porous carbons have immense potential for high-performance SCs application.

Superionic Lithium Intercalation through 2 nm x 2 nm Columns in the Crystallographic Shear Phase Nb18W8O69

2019 ◽  
Author(s):  
Kent Griffith ◽  
Clare Grey
Keyword(s):  
High Performance ◽  
Rate Capability ◽  
Block Size ◽  
Lithium Intercalation ◽  
Resonance Spectroscopy ◽  
Complex Metal Oxides ◽  
Battery Electrode ◽  
Crystallographic Shear ◽  
Battery Material ◽  
First Time

Nb18W8O69 (9Nb2O5×8WO3) is the tungsten-rich end-member of the Wadsley–Roth crystallographic shear (cs) structures within the Nb2O5–WO3 series. It has the largest block size of any known, stable Wadsley–Roth phase, comprising 5 ´ 5 units of corner-shared MO6 octahedra between the shear planes, giving rise to 2 nm ´ 2 nm blocks. Rapid lithium intercalation is observed in this new candidate battery material and 7Li pulsed field gradient nuclear magnetic resonance spectroscopy – measured in a battery electrode for the first time at room temperature – reveals superionic lithium conductivity. In addition to its promising rate capability, Nb18W8O69 adds a piece to the larger picture of our understanding of high-performance Wadsley–Roth complex metal oxides.

scholarly journals Aerogel Based High Performance Thermal Insulation Materials

2019 ◽  
Vol 553 ◽  
pp. 012043
Author(s):  
Mohanapriya Venkataraman ◽  
Rajesh Mishra ◽  
Jiri Militky ◽  
Dana Kremenakova ◽  
Petru Michal
Keyword(s):  
Thermal Insulation ◽  
High Performance ◽  
Insulation Materials

Study of Transcrystallization in Polymer Composites

1989 ◽  
Vol 170 ◽  
Author(s):  
Benjamin S. Hsiao ◽  
J. H. Eric
Keyword(s):  
Thermal Conductivity ◽  
Free Energy ◽  
Carbon Fiber ◽  
Plasma Treatment ◽  
Polymer Composites ◽  
High Performance ◽  
Interfacial Strength ◽  
Fiber Surface ◽  
Semicrystalline Polymers ◽  
First Case

AbstractTranscrystallization of semicrystalline polymers, such as PEEK, PEKK and PPS, in high performance composites has been investigated. It is found that PPDT aramid fiber and pitch-based carbon fiber induce a transcrystalline interphase in all three polymers, whereas in PAN-based carbon fiber and glass fiber systems, transcrystallization occurs only under specific circumstances. Epitaxy is used to explain the surface-induced transcrystalline interphase in the first case. In the latter case, transcrystallization is probably not due to epitaxy, but may be attributed to the thermal conductivity mismatch. Plasma treatment on the fiber surface showed a negligible effect on inducing transcrystallization, implying that surface-free energy was not important. A microdebonding test was adopted to evaluate the interfacial strength between the fiber and matrix. Our preliminary results did not reveal any effect on the fiber/matrix interfacial strength of transcrystallinity.

scholarly journals One-Pot Synthesis of Glucose-Derived Carbon Coated Ni3S2 Nanowires as a Battery-Type Electrode for High Performance Supercapacitors

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 678
Author(s):  
Zhongkai Wu ◽  
Haifu Huang ◽  
Wenhui Xiong ◽  
Shiming Yang ◽  
Huanhuan Huang ◽  
...  
Keyword(s):  
Carbon Source ◽  
High Performance ◽  
Specific Capacity ◽  
Rate Capability ◽  
One Pot ◽  
Great Performance ◽  
Carbon Coated ◽  
Binder Free ◽  
Coated Carbon ◽  
Supercapacitor Applications

We report a novel Ni3S2 carbon coated (denoted as NCC) rod-like structure prepared by a facile one-pot hydrothermal method and employ it as a binder free electrode in supercapacitor. We coated carbon with glucose as carbon source on the surface of samples and investigated the suitable glucose concentration. The as-obtained NCC rod-like structure demonstrated great performance with a huge specific capacity of 657 C g−1 at 1 A g−1, preeminent rate capability of 87.7% retention, the current density varying to 10 A g−1, and great cycling stability of 76.7% of its original value through 3500 cycles, which is superior to the properties of bare Ni3S2. The result presents a facile, general, viable strategy to constructing a high-performance material for the supercapacitor applications.

scholarly journals Oxygen-Deficient Stannic Oxide/Graphene for Ultrahigh-Performance Supercapacitors and Gas Sensors

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 372
Author(s):  
Liyang Lin ◽  
Susu Chen ◽  
Tao Deng ◽  
Wen Zeng
Keyword(s):  
Energy Storage ◽  
Gas Sensors ◽  
High Performance ◽  
Gas Sensing ◽  
Synthesis Method ◽  
Rate Capability ◽  
Stannic Oxide ◽  
Energy Storage Devices ◽  
Graphene Nanocomposites ◽  
Storage Devices

The metal oxides/graphene nanocomposites have great application prospects in the fields of electrochemical energy storage and gas sensing detection. However, rational synthesis of such materials with good conductivity and electrochemical activity is the topical challenge for high-performance devices. Here, SnO2/graphene nanocomposite is taken as a typical example and develops a universal synthesis method that overcome these challenges and prepares the oxygen-deficient SnO2 hollow nanospheres/graphene (r-SnO2/GN) nanocomposite with excellent performance for supercapacitors and gas sensors. The electrode r-SnO2/GN exhibits specific capacitance of 947.4 F g−1 at a current density of 2 mA cm−2 and of 640.0 F g−1 even at 20 mA cm−2, showing remarkable rate capability. For gas-sensing application, the sensor r-SnO2/GN showed good sensitivity (~13.8 under 500 ppm) and short response/recovering time toward methane gas. These performance features make r-SnO2/GN nanocomposite a promising candidate for high-performance energy storage devices and gas sensors.

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