02
Junyan Zhang, Junjie Zhang, Mengyue Gao, et al. Nacre-Mimetic Nanocomposite Aerogels with Exceptional Mechanical Performance for Thermal Superinsulation at Extreme Conditions[J]. Advanced Materials.
總結(jié)：該文研究基于跨維度、跨尺度的結(jié)構(gòu)適配工作原理，該有機(jī)無(wú)機(jī)納米復(fù)合SCQs在環(huán)境壓力干燥過(guò)程中具有快速結(jié)構(gòu)回復(fù)能力，為氣凝膠材料的低成本規(guī)?；苽涞於ɑA(chǔ)。另一方面，該氣凝膠具有優(yōu)異的絕熱性能，熱導(dǎo)率值低至17.4 mW/mK，遠(yuǎn)低于理想的絕熱體-靜止的空氣，與目前航天用隔熱材料-多層隔熱氈相比，不僅具有更優(yōu)異的耐熱性能，而且在一個(gè)大氣壓或稀薄氣壓環(huán)境均具有更優(yōu)異的隔熱性能。
抽象：Thermal protection under extreme conditions requires materials with excellent thermal insulation properties and exceptional mechanical properties to withstand a variety of complex external stresses. Mesoporous silica aerogels are the most widely used insulation materials due to their ultralow thermal conductivity. However, they still suffer from mechanical fragility and structural instability in practical applications. Herein, a nacre-mimetic nanocomposite aerogel, synthesized via in situ growth of inorganic minerals in a lamellar cellulose nanofibrous network, is reported. The multiscale structural adaptation of the inorganic–organic components endows nanocomposite aerogels with rapid configuration recovery during ambient pressure drying. The resulting aerogels show ultralow thermal conductivities (17.4 mW/mK at 1.0 atm). These aerogels also integrate challenging mechanical properties, including high compressive stiffness to resist deformation under the pressure of an adult, superelasticity to prevent static and dynamic stress cracking even under the crushing of a vehicle (1.6 t), and high bending flexibility to adapt to any surface. Moreover, they exhibit excellent structural stability under fatigue stress/strain cycles over a wide temperature range (?196 to 200 °C). The combination of high thermal insulation performance and excellent mechanical properties offers a potential material system for robust thermal superinsulation under extreme conditions, especially for aerospace applications.
03
Jing Wang, Dengsen Yuan, Peiying Hu, et al. Optical Design of Silica Aerogels for On-Demand Thermal Management[J]. Advanced Functional Materials.
總結(jié)：該文研究揭示了二氧化硅氣凝膠在不同環(huán)境下被動(dòng)保溫、被動(dòng)加熱或被動(dòng)冷卻的按需熱管理（ODTM）。二氧化硅氣凝膠的ODTM行為可以簡(jiǎn)單地通過(guò)其光學(xué)性質(zhì)的變化來(lái)實(shí)現(xiàn)，例如太陽(yáng)光透明度和紅外發(fā)射率，這些變化可以通過(guò)構(gòu)建塊的微觀結(jié)構(gòu)和表面成分設(shè)計(jì)來(lái)控制。該研究指導(dǎo)了對(duì)二氧化硅氣凝膠熱管理行為的全面理解，并通過(guò)調(diào)整二氧化硅氣凝膠的光學(xué)和導(dǎo)熱性能，導(dǎo)致二氧化硅氣凝膠的ODTM應(yīng)用。
抽象：Silica aerogels, a type of porous material featuring extra low density and thermal conductivity, have drawn increasing interest from both academia and industry owing to their excellent thermal insulation performance. However, thermal insulation is always the single consideration when silica aerogels are used for thermal management. In this study, the on-demand thermal management (ODTM) of silica aerogel with either passive thermal insulation, passive heating, or passive cooling in different environments is revealed. The ODTM behavior of silica aerogels can be simply fulfilled through their optical property variations such as solar light transparency and infrared emissivity, which are controllable via the microstructures of the building blocks and surface composition design. Robust solar heating of 25 °C higher than the ambient in the daytime and sub-ambient cooling of 7 °C at night is achieved with the traditional transparent silica aerogel. Interestingly, sub-ambient cooling of 5 °C in the daytime and a warmer state on cold nights is achieved by modifying its solar transmittance and infrared emissivity. This study guides a comprehensive understanding of the thermal management behavior of silica aerogels and leads to ODTM applications of silica aerogels by tailoring their optical and thermal conductivity properties.
04
Liyuan Han, Kezhi Li, Huimin Liu, et al.
Heterogeneous stacking strategy towards carbon aerogel for thermal management and electromagnetic interference shielding [J].
Chemical Engineering Journal.
總結(jié)：該文通過(guò)化學(xué)氣相沉積技術(shù)，實(shí)現(xiàn)了還原氧化石墨烯-碳納米管-垂直富邊石墨烯(rGO-CNT-VG)的共價(jià)鍵復(fù)合的三維結(jié)構(gòu)。基于微結(jié)構(gòu)的設(shè)計(jì)和控制，成功獲得的層疊式三維rGO-CNT-VG骨架在不同組分之間具有大量無(wú)縫結(jié)合的異質(zhì)界面，可以產(chǎn)生額外的電荷極化、界面極化和介電弛豫，從而顯著促進(jìn)電磁微波的衰減和轉(zhuǎn)換，達(dá)到理想的電磁干擾屏蔽性能。值得關(guān)注的是，rGO-CNT-VG /環(huán)氧復(fù)合材料的導(dǎo)熱系數(shù)為2.46 W/mK，EMI屏蔽效率為56.65 dB，分別是rGO/環(huán)氧復(fù)合材料的5.1倍和1.9倍。
Abstract: Faced with the increasing heat dissipation and electromagnetic interference (EMI) shielding problems in electronics, carbon modified polymer-based composites with significant EMI shielding and thermal management performance are of particular interest. Herein, we proposed a carbon heterogeneous stacking strategy to construct the all carbon aerogels for the modification of epoxy resin. A hybrid 3D structure of reduced graphene oxide–carbon nanotube-vertical edge-rich graphene (rGO-CNT-VG) with covalent bonding are achieved all by chemical vapor deposition, in which the pore space of skeleton is creatively modified. Due to the elaborate design and control of microstructures, the obtained hierarchical 3D rGO-CNT-VG skeleton have plenty of seamlessly bonded heterogeneous interfaces between different components, which can create additional charge polarization, interfacial polarization and dielectric relaxation to promote significantly electromagnetic microwave attenuation and conversion and achieve ideal EMI shielding performance. Impressively, the rGO-CNT-VG/epoxy composites possess excellent thermal conductivity of 2.46 W/mK and EMI shielding effectiveness of 56.65 dB, which are 5.1 times and 1.9 times higher than those of the rGO/epoxy composites, respectively. More importantly, the strategy of designing all carbon heterogeneous stacking skeleton in this study provides a guidance for synergistic controlling of multifunctional performance of composites.
05
MiracleHope Adegun, KitYing Chan, Jie Yang, et al. Composites Part A: Applied Science and Manufacturing[J]. Composites Part A: Applied Science and Manufacturing.
總結(jié)：該文采用單向冷凍鑄造技術(shù)制備了各向異性氮化硼納米片(BNNs)/聚乙烯醇復(fù)合氣凝膠。與傳統(tǒng)氧化硅或氧化鋁基氣凝膠中相互連接的各向同性納米顆粒形成的開(kāi)孔結(jié)構(gòu)不同，二維BNNS可以將氣凝膠分隔成獨(dú)立的細(xì)胞，有效減少空氣傳導(dǎo)和對(duì)流，從而實(shí)現(xiàn)超低導(dǎo)熱。得益于BNNs排列的多孔結(jié)構(gòu)，具有最佳BNNS含量的復(fù)合氣凝膠在具有20.3 mW/mK的超低導(dǎo)熱系數(shù)。
Abstract: Thermally insulating materials are commonly used to reduce energy consumption in buildings. Most commercial products possess only low thermal conductivities but poor insulating capabilities in the daytime with little sunlight reflectance and thermal emittance. It is challenging to achieve all traits in the same material. Herein, anisotropic boron nitride nanosheet (BNNS)/polyvinyl alcohol composite aerogels are developed using the unidirectional freeze-casting technique. Benefitting from the aligned porous structure, the composite aerogel with an optimal BNNS content exhibits a combination of an ultralow TC of 20.3 mW/mK in the through-thickness direction, a high solar-weighted reflectance of 95.0 % over the whole sunlight wavelength and a high emittance of above 93 % within the atmospheric transparency window. These exceptional thermo-optical properties enable the composite aerogel to maintain the interior temperature much cooler than commercially available foams, making them promising candidates as superinsulating envelopes for energy saving in buildings towards carbon neutrality.
06
Fengyin Du, Wenkai Zhu, Ruizhe Yang, et al. Bioinspired Super Thermal Insulating, Strong and Low Carbon Cement Aerogel for Building Envelope[J]. Advanced Science.
總結(jié)：該文所得水泥氣凝膠的質(zhì)量密度僅為0.015 g/cm3。合成的水泥氣凝膠在剛度(315.65 MPa)和韌性(14.68 MJ/m3)方面表現(xiàn)出超高的力學(xué)性能。水泥氣凝膠內(nèi)部具有多尺度孔隙的高孔隙結(jié)構(gòu)極大地抑制了傳熱，從而實(shí)現(xiàn)了超低導(dǎo)熱系數(shù)(0.025 W/(mK))。此外，無(wú)機(jī)C-A-S-H納米顆粒在水泥氣凝膠中形成防火屏障，具有良好的阻燃性（極限氧指數(shù)高達(dá)46.26%，UL94-V0）。
Abstract: The composite films filled with anisotropic flaky powders usually have excellent in-plane thermal conductivity, The energy crisis has arisen as the most pressing concern and top priority for policymakers, with buildings accounting for over 40% of global energy consumption. Currently, single-function envelopes cannot satisfy energy efficiency for next-generation buildings. Designing buildings with high mechanical robustness, thermal insulation properties, and more functionalities has attracted worldwide attention. Further optimization based on bioinspired design and material efficiency improvement has been adopted as effective approaches to achieve satisfactory performance. Herein, inspired by the strong and porous cuttlefish bone, a cement aerogel through self-assembly of calcium aluminum silicate hydrate nanoparticles (C-A-S-H, a major component in cement) in a polymeric solution as a building envelop is developed. The as-synthesized cement aerogel demonstrates ultrahigh mechanical performance in terms of stiffness (315.65 MPa) and toughness (14.68 MJ m?3). Specifically, the highly porous microstructure with multiscale pores inside the cement aerogel greatly inhibits heat transfer, therefore achieving ultralow thermal conductivity (0.025 W/mK). Additionally, the inorganic C-A-S-H nanoparticles in cement aerogel form a barrier against fire for good fire retardancy (limit oxygen index, LOI ≈ 46.26%, UL94-V0). The versatile cement aerogel featuring high mechanical robustness, remarkable thermal insulation, light weight, and fire retardancy is a promising candidate for practical building applications.
07
Weiqing Yang, Peng Xiao, Shan Li, et al. Engineering Structural Janus MXene-nanofibrils Aerogels for Season-Adaptive Radiative Thermal Regulation[J]. Small.
總結(jié)：該研究用免凍干的方法，設(shè)計(jì)了由光熱MXene-CNF層和CNF層組成的Janus結(jié)構(gòu)氣凝膠（JMNA）。該氣凝膠能夠?qū)崿F(xiàn)可切換的熱調(diào)節(jié)，將被動(dòng)輻射冷卻和加熱集成到一個(gè)材料系統(tǒng)中，以適應(yīng)多變的環(huán)境。
Abstract: Aerogels have provided a significant platform for passive radiation-enabled thermal regulation, arousing extensive interest due to their capabilities of radiative cooling or heating. However, there still remains challenge of developing functionally integrated aerogels for sustainable thermal regulation in both hot and cold environment. Here, Janus structured MXene-nanofibrils aerogel (JMNA) is rationally designed via a facile and efficient way. The achieved aerogel presents the characteristic of high porosity (≈98.2%), good mechanical strength (tensile stress of ≈2 MPa, compressive stress of ≈115 kPa), and macroscopic shaping property. Based on the asymmetric structure, the JMNA with switchable functional layers can alternatively enable passive radiative heating and cooling in winter and summer, respectively. As a proof of concept, JMNA can function as a switchable thermal-regulated roof to effectively enable the inner house model to maintain >25 °C in winter and <30 °C in hot summer. This design of Janus structured aerogels with compatible and expandable capabilities is promising to widely benefit the low-energy thermal regulation in changeable climate.
08
Yue Xu, Chentao Yan, Chunlin Du, et al.
High-strength, thermal-insulating, fire-safe bio-based organic lightweight aerogel based on 3D network construction of natural tubular fibers[J].
Composites Part B.
總結(jié)：該文提出以天然中空隔熱動(dòng)物毛發(fā)為靈感，采用中空木棉纖維(KF)、粘結(jié)劑聚乙烯醇(PVA)和阻燃交聯(lián)劑膦酸雙胍酯(BGP)構(gòu)建了管狀氣凝膠的三維網(wǎng)絡(luò)結(jié)構(gòu)。通過(guò)冷凍成型和冷凍干燥，成功制備了集保溫、高強(qiáng)、防火為一體的多功能管狀氣凝膠。由于分子間氫鍵和粘結(jié)劑的高粘度，KF保持了高填充、全組分和高價(jià)值利用率。與純KF相比，KF- PVA - BGP氣凝膠的導(dǎo)熱系數(shù)降低到0.0531 W/mK，抗壓強(qiáng)度提高到1.64 MPa。
Abstract: Petrochemical-based foam materials are extensively used in insulation and energy storage fields. However, their non-degradability and high flammability have caused great pressure on energy, environment and human life and property safety. It is urgent to carry out research on biodegradable and fire safety alternative biomaterials. Herein, inspired by the natural hollow insulation animal hair, the 3D network structure of tubular aerogel was constructed by using the hollow kapok fibers (KF), the binder polyvinyl alcohol and the flame retardant crosslinker biguanide phosphonate. The multifunctional tubular aerogel integrating thermal insulation, high strength and fire safety was successfully prepared by freeze-forming and freeze-drying. Due to the intermolecular hydrogen bonding and the high viscosity of binder, KF maintained a high filling, full component and high value utilization. Compared to pure KF, the thermal conductivity of KF-PVA-BGP aerogel was reduced to 0.0531 W/mK and its compressive strength was improved to 1.64 MPa. Meanwhile, the incorporation of flame retardant cross-linker BGP promoted the degradation and charring of KF-PVA aerogel and released lots of inert gases during decomposition process, which effectively exerted the flame retardant effect in condensed and gas phases. Besides, compared with commercial PS insulation boards, KF-PVA-BGP composites are recyclable, sustainable and biodegradable in addition to their excellent thermal insulation and fire safety performance. This KF-PVA-BGP aerogel showed good application prospects for replacing traditional petrochemical-based materials in thermal insulation, energy storage and new energy fields.
09
Zechang Wei, Yaoxin Zhang, Chenyang Cai, et al.
Wood Lamella-Inspired Photothermal Stearic Acid-Eutectic Gallium-Indium-Based Phase Change Aerogel for Thermal Management and Infrared Stealth[J].
Small.
總結(jié)：本研究通過(guò)簡(jiǎn)單的機(jī)械球磨工藝制備了一種具有優(yōu)異光吸收性能的新型EGaIn基相變儲(chǔ)能材料(STA-EGaIn)。采用定向冷凍干燥法和烷基化反應(yīng)法制備了木片激發(fā)纖維素納米晶氣凝膠，同時(shí)提高了木片激發(fā)纖維素納米晶氣凝膠的防漏和浸漬性能。為了提高STA-EGaIn的導(dǎo)熱性能和光熱性能，引入MoS2來(lái)降低STA-EGaIn的界面熱阻，調(diào)整EGaIn基相變儲(chǔ)能復(fù)合材料的光吸收性能。
Abstract: Eutectic Gallium-Indium (EGaIn) liquid metal is an emerging phase change metal material, but its low phase transition enthalpy and low light absorption limit its application in photothermal phase change energy storage materials (PCMs) field. Here, based on the dipole layer mechanism, stearic acid (STA)-EGaIn-based PCMs which exhibit extraordinary solar-thermal performance and phase change enthalpy are fabricated by ball milling method. The wood lamella-inspired cellulose-derived aerogel and molybdenum disulfide (MoS2) are used to support the PCMs by the capillary force and decrease the interfacial thermal resistance. The resulted PCMs achieved excellent photothermal conversion performance and leakage proof. They have excellent thermal conductivity of 0.31 W/mK (this is increased by 138% as compared with pure STA), and high phase change enthalpy of187.50 J g?1, which is higher than the most of the reported PCMs. Additionally, the thermal management system and infrared stealth materials based on the PCMs are developed. This work provides a new way to fabricate smart EGaIn-based PCMs for energy storage device thermal management and infrared stealth.
10
Yijing Zhao, Haobo Qi, Xinyu Dong, et al.
Customizable Resilient Multifunctional Graphene Aerogels via Blend-spinning assisted Freeze Casting[J].
ACS Nano.
總結(jié)：該文提出了一種混合-紡絲輔助冷凍鑄造（BSFC）策略，將顆粒改性碳纖維加入石墨烯氣凝膠中，以實(shí)現(xiàn)機(jī)械強(qiáng)化和功能增強(qiáng)。這種方法為創(chuàng)造可定制的多材料、多尺度結(jié)構(gòu)石墨烯氣凝膠提供了極大的自由度。例如，我們制造了碳化硅顆粒改性碳纖維增強(qiáng)石墨烯（SiC/CF-GA）氣凝膠。所制備的氣凝膠具有超輕、高彈性、抗疲勞壓縮（50%應(yīng)變下1000次循環(huán)）等優(yōu)異性能。同時(shí)，增強(qiáng)的彈性激發(fā)了 SiC/CF-GA 氣凝膠的有效應(yīng)變傳感能力，其靈敏度高達(dá)13.8 k/Pa。
Abstract: Graphene aerogels have gained considerable attention due to their unique physical properties, but their poor mechanical properties and lack of functionality have hindered their advanced applications. In this study, we propose a blend-spinning-assisted freeze-casting (BSFC) strategy to incorporate particle-modified carbon fibers into graphene aerogels for mechanical strengthening and functional enhancement. This method offers a great deal of freedom in the creation of customizable multimaterial, multiscale structural graphene aerogels. For example, we fabricated silicon carbide particle modified carbon fiber reinforced graphene (SiC/CF-GA) aerogels. The resulting aerogels display excellent properties such as being ultralightweight and highly resilient and having fatigue compression resistance (1000 cycles at 50% strain). Meanwhile, enhanced resilience inspired the effective strain-sensing capabilities of SiC/CF-GA aerogels with a sensitivity of 13.8 k/Pa. The adjustable dielectric properties due to SiC particle incorporation endow the SiC/CF-GA aerogel with a broad-band (8.0 GHz) effective electromagnetic wave attenuation performance. Besides, different particles could be incorporated into graphene aerogels via the BSFC strategy, allowing for customizable designs. Moreover, multifunctionalities were demonstrated by the modified aerogels, including noise absorption, thermal insulation, fire resistance, and waterproofing, further diversifying their practicality. Hence, the BSFC strategy provides a customized solution for fabricating modified graphene aerogels for advanced functional applications.
