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.
总结：该文研究基于跨维度、跨尺度的结构适配工作原理，该有机无机纳米复合SCQs在环境压力干燥过程中具有快速结构回复能力，为气凝胶材料的低成本规模化制备奠定基础。另一方面，该气凝胶具有优异的绝热性能，热导率值低至17.4 mW/mK，远低于理想的绝热体-静止的空气，与目前航天用隔热材料-多层隔热毡相比，不仅具有更优异的耐热性能，而且在一个大气压或稀薄气压环境均具有更优异的隔热性能。
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.
总结：该文研究揭示了二氧化硅气凝胶在不同环境下被动保温、被动加热或被动冷却的按需热管理（ODTM）。二氧化硅气凝胶的ODTM行为可以简单地通过其光学性质的变化来实现，例如太阳光透明度和红外发射率，这些变化可以通过构建块的微观结构和表面成分设计来控制。该研究指导了对二氧化硅气凝胶热管理行为的全面理解，并通过调整二氧化硅气凝胶的光学和导热性能，导致二氧化硅气凝胶的ODTM应用。
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.
总结：该文通过化学气相沉积技术，实现了还原氧化石墨烯-碳纳米管-垂直富边石墨烯(rGO-CNT-VG)的共价键复合的三维结构。基于微结构的设计和控制，成功获得的层叠式三维rGO-CNT-VG骨架在不同组分之间具有大量无缝结合的异质界面，可以产生额外的电荷极化、界面极化和介电弛豫，从而显著促进电磁微波的衰减和转换，达到理想的电磁干扰屏蔽性能。值得关注的是，rGO-CNT-VG /环氧复合材料的导热系数为2.46 W/mK，EMI屏蔽效率为56.65 dB，分别是rGO/环氧复合材料的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.
总结：该文采用单向冷冻铸造技术制备了各向异性氮化硼纳米片(BNNs)/聚乙烯醇复合气凝胶。与传统氧化硅或氧化铝基气凝胶中相互连接的各向同性纳米颗粒形成的开孔结构不同，二维BNNS可以将气凝胶分隔成独立的细胞，有效减少空气传导和对流，从而实现超低导热。得益于BNNs排列的多孔结构，具有最佳BNNS含量的复合气凝胶在具有20.3 mW/mK的超低导热系数。
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.
总结：该文所得水泥气凝胶的质量密度仅为0.015 g/cm3。合成的水泥气凝胶在刚度(315.65 MPa)和韧性(14.68 MJ/m3)方面表现出超高的力学性能。水泥气凝胶内部具有多尺度孔隙的高孔隙结构极大地抑制了传热，从而实现了超低导热系数(0.025 W/(mK))。此外，无机C-A-S-H纳米颗粒在水泥气凝胶中形成防火屏障，具有良好的阻燃性（极限氧指数高达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.
总结：该研究用免冻干的方法，设计了由光热MXene-CNF层和CNF层组成的Janus结构气凝胶（JMNA）。该气凝胶能够实现可切换的热调节，将被动辐射冷却和加热集成到一个材料系统中，以适应多变的环境。
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.
总结：该文提出以天然中空隔热动物毛发为灵感，采用中空木棉纤维(KF)、粘结剂聚乙烯醇(PVA)和阻燃交联剂膦酸双胍酯(BGP)构建了管状气凝胶的三维网络结构。通过冷冻成型和冷冻干燥，成功制备了集保温、高强、防火为一体的多功能管状气凝胶。由于分子间氢键和粘结剂的高粘度，KF保持了高填充、全组分和高价值利用率。与纯KF相比，KF- PVA - BGP气凝胶的导热系数降低到0.0531 W/mK，抗压强度提高到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.
总结：本研究通过简单的机械球磨工艺制备了一种具有优异光吸收性能的新型EGaIn基相变储能材料(STA-EGaIn)。采用定向冷冻干燥法和烷基化反应法制备了木片激发纤维素纳米晶气凝胶，同时提高了木片激发纤维素纳米晶气凝胶的防漏和浸渍性能。为了提高STA-EGaIn的导热性能和光热性能，引入MoS2来降低STA-EGaIn的界面热阻，调整EGaIn基相变储能复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.
总结：该文提出了一种混合-纺丝辅助冷冻铸造（BSFC）策略，将颗粒改性碳纤维加入石墨烯气凝胶中，以实现机械强化和功能增强。这种方法为创造可定制的多材料、多尺度结构石墨烯气凝胶提供了极大的自由度。例如，我们制造了碳化硅颗粒改性碳纤维增强石墨烯（SiC/CF-GA）气凝胶。所制备的气凝胶具有超轻、高弹性、抗疲劳压缩（50%应变下1000次循环）等优异性能。同时，增强的弹性激发了 SiC/CF-GA 气凝胶的有效应变传感能力，其灵敏度高达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.
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