共查询到20条相似文献,搜索用时 15 毫秒
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Junyan Zhang Yanhua Cheng Mike Tebyetekerwa Si Meng Meifang Zhu Yunfeng Lu 《Advanced functional materials》2019,29(15)
Designing aerogel materials featuring both high thermal insulation property and excellent mechanical robustness is of great interest for applications in superior integrated energy management systems. To meet the above requirements, composite aerogels based on hierarchical “stiff–soft” binary networks are reported, in which secondary mesoporous polymethylsilsesquioxane domains intertwined by bacterial cellulose nanofibrillar networks are connected in tandem. The resulting composite aerogels are characterized by highly porous (93.6%) and nanosized structure with a surface area of 660 m2 g?1, leading to the excellent thermal insulation performance with a low thermal conductivity of 15.3 mW m?1 K?1. The integrated “stiff–soft” binary nature also endows the composite aerogels with high flexibility that can conform to various substrates as well as large tensile strength that can withstand more than 2.70 × 104 times its own weight. These composite aerogels show multifunctionality in terms of efficient wearable protection, controllable thermal management, and ultrafast oil/water separation. These favorable multifeatures present composite aerogels ideal for aerospace, industrial, and commercial applications. 相似文献
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Jiaying Zhu Yeling Zhu Yuhang Ye Zhe Qiu Yifan Zhang Zhengyang Yu Xia Sun David C. Bressler Feng Jiang 《Advanced functional materials》2023,33(22):2300893
Aerogels with both high elastic strain and fast shape recovery after compression have broad application potentials as thermal regulation, absorbents, and electrical devices. However, creating such aerogels from cellulosic materials requires complicated preparation processes. Herein, a simple strategy for scalable production of hemp microfibers using a top-down method is reported, which can further be assembled into aerogels with interconnected porous structures via ice-templating technique. With density as low as 2.1 mg cm−3, these aerogels demonstrate isotropic superelasticity, as exhibited by their fast shape restoration from over 80% compressive strain. Due to the high porosity (99.87%) and structural tortuosity, these aerogels show a low thermal conductivity of 0.0215 ± 0.0002 W m−1 K−1, suggesting their potential in thermal insulation application. Certain hydrophobic modification using silane derivative further endows these aerogels with reduced water affinity. Overall, the proposed strategy to prepare bio-based microfibers using scalable technology, as well as the assembled aerogels, provides new insights into the design and fabrication of multifunctional bio-based aerogels for value-added applications. 相似文献
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Lightweight aerogels with large specific surface area (SSA) have numerous applications. Free‐standing aerogels are created from single‐walled carbon nanotubes (SWCNTs), and their SSA and pore characteristics, electrical conductivity, mechanical properties, and thermal management attributes are determined. The SSA of the aerogels is extraordinarily high and approaches 1291 m2 g?1 at a density of 7.3 mg mL?1, which is close to the theoretical limit (≈1315 m2 g?1). Mechanical characterization shows that these aerogels have open‐cell structures and their Young's moduli are higher than other aerogels at comparable density. The aerogels also enhance heat transfer in a forced convective process by ≈85%, presumably due to their large porosity and surface area. 相似文献
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Ya Li Xiaofang Liu Xiaoyu Nie Wenwen Yang Yidong Wang Ronghai Yu Jianglan Shui 《Advanced functional materials》2019,29(10)
Multifunctionalization is the future development direction for microwave absorbing materials, but has not yet been explored. The effective integration of multiple functions into one material remains a huge challenge. Herein, an aerogel‐type microwave absorber assembled with multidimensional organic and inorganic components is synthesized. Polyacrylonitrile fibers and polybenzoxazine membranes work as the skeleton and crosslinker, respectively, forming a 3D framework, in which carbon nanotubes are interconnected into an electrically conductive network, and Fe3O4 nanoparticles are uniformly dispersed throughout the aerogel. Remarkably, the microwave absorption performances of the aerogel achieve ultralight, ultrathin (1.5 mm), and strong absorption (reflection loss of ?59.85 dB) features. In particular, its specific reflection loss values considerably outperform the current magnetic–dielectric hybrids with similar components. Moreover, the aerogel possesses strong hydrophobicity and good thermal insulation, endowing it attractive functions of self‐cleaning, infrared stealth, and heat insulation that is even comparable to commercial products. The excellent multifunction benefits from the cellular structure of aerogel, the assembly of multidimensional nanomaterials, and the synergistic effect of organic–inorganic components. This study paves the way for designing next‐generation microwave absorbing materials with great potential for multifunctional applications. 相似文献
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关于半导体器件热特性表征和控制技术的研究 总被引:3,自引:2,他引:1
根据对器件散热特性的分析,提出用特定脉宽的瞬态热阻抗表征器件的稳态散热特性.测量了特定器件热阻与温度的依赖关系,建议在实际工作中注意器件热阻并不为常数的客观事实.提出应力试验前后测量器件热阻可有效控制器件的某些制造缺陷. 相似文献
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Linfeng Cai Jianfeng Fan Shengchang Ding Dongyi He Xiangliang Zeng Rong Sun Linlin Ren Jianbin Xu Xiaoliang Zeng 《Advanced functional materials》2023,33(2):2207143
Soft gels with high toughness have drawn tremendous attention recently due to their potential applications in flexible electronic fields. The miniaturization and high-power density of electronic devices require soft gels with both high toughness and low thermal resistance; however, it is difficult to achieve these properties simultaneously. Herein, a simple design strategy is reported for constructing soft (high stretchability of 6.91 and low Young's modulus of 340 kPa), tough (4741.48 J m−2) and thermal conductive (low thermal resistance of 0.14 cm2 K W−1, under 10 psi pressure) polydimethylsiloxane/aluminum composite gel. This is realized by precisely lengthening polymer strands between the chemical cross-linked points and controlling the aluminum content in the composite gels. The symbiosis of this combination involves: lengthening the polymer strands facilitates its unfolding to increase the softness and intrinsic toughness; the thermally conductive spherical aluminum enables low thermal resistance and increases the intrinsic toughness and stress dissipation. By utilizing this gel as a thermal interface material, effective heat dissipation is demonstrated in electronic devices operating under high-power conditions over numerous cycles. These results demonstrate the application potential of composite gels in meeting the performance maintenance and heat dissipation, which are needed for modern electronic devices. 相似文献
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Zilong Xie Zhengli Dou Die Wu Xiangtong Zeng Yuan Feng Yunfei Tian Qiang Fu Kai Wu 《Advanced functional materials》2023,33(14):2214071
For advanced thermal interface materials (TIMs), massive inorganic addition for high isotropic thermal conductivities conflicts with suitable rheological viscosity for low contact thermal resistance. Traditional strategies rarely resolve such a contradiction, and it remains an academic and industrial challenge. Herein, inspired by the structure and function of the bone joint, a best-of-both-worlds approach is reported that endows a standard polydimethylsiloxane/alumina (PDMS/Al2O3) TIM with simultaneously enhanced rheological mobility and thermal conductivity. It is conducted by employing morphology-controllable gallium-based liquid metal (LM) to the surface of Al2O3 by a scalable mechanochemical process. At the typical polymer-LM-Al2O3 interface, LM droplets with low cohesive energy can release the freedom for macromolecular chain relaxation and reduce the viscosity, successfully allowing the high-loading TIMs (79 vol.%) to keep the thixotropic state and effectively reducing its contact thermal resistance with a copper substrate by 65%. At the same time, adjacent LMs merge to thermally bridge separate Al2O3 particles, which facilitates the interfacial thermal conduction and enhances the thermal conductivity from 5.9 to 6.7 W m−1 K−1. Along with additional electrical insulation, this filler modification strategy is believed to inspire others to develop high-performance polymer-based TIMs for future advanced electronics. 相似文献
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Wei Gao Zhouyue Lei Chengbin Zhang Xiangdong Liu Yongping Chen 《Advanced functional materials》2021,31(43):2104071
Aqueous thermocells that are eco-friendly and capable of converting low-grade heat into electricity continuously are promising candidates to power flexible and wearable devices in various application scenarios. However, challenges remain in their limited working temperatures, mechanical fragility, and poor thermoelectric performance, mainly due to the reduced entropy of both polymer chains and thermogalvanic ions at low temperatures. In this work, the challenges are addressed by introducing a synergistic chaotropic effect to destruct strong hydrogen bonds, increase polymers’ entropic elasticity, and enlarge the entropy difference of thermogalvanic ions. An organohydrogel thermocell is designed with a chaotropic comonomer and a chaotropic cosolvent. The maximum normalized power density of the thermocell achieves 0.1 mW m−2 K−2, which is in the same order of magnitude as the highest record in current quasi-solid thermocells. Even at −30 °C, the thermocell maintains the elongation at a break of more than 100% and a relatively high power density of 0.012 mW m−2 K−2. Furthermore, the thermocell shows the potential to light up a light-emitting diode and stably works when compressed, bent, and stretched in a wide temperature range. This work provides insights on developing reliable power sources to drive flexible electronics continually in extremely cold environments. 相似文献
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高抗热震性红外辐射节能涂层的制备与性能研究 总被引:1,自引:0,他引:1
以堇青石、SiC、Cr2O3、TiO2、SiO2为原料,与磷酸盐胶粘结剂配料混匀后,经机械搅拌制备红外辐射涂料,采用刷涂的方式在高铝砖基体表面制备红外辐射节能涂层。采用TG-DSC研究分析红外辐射粉末的热稳定性,利用涂-4杯和漆膜附着力测定仪对涂料的流动性能和涂层与基体的结合强度进行表征,采用空冷和水淬方式研究涂层的抗热震性能,并探讨了碳化硅的含量对涂层红外发射率的影响。研究结果表明:胶粉比为2:1时,获得的涂料均匀,流动性最好;以磷酸盐胶粘结剂制备的红外辐射涂料经1100℃以上高温瓷化后,红外辐射涂层与基体的结合力增强,涂层抗热震性能良好;碳化硅含量为40%时,制备的复合红外辐射涂层具有最优的红外辐射性能。此外,在炭砖焙烧窑上使用该红外辐射涂料后,炉内温度提高了128℃,降低能耗8%左右。 相似文献
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Dual Support System Ensuring Porous Co–Al Hydroxide Nanosheets with Ultrahigh Rate Performance and High Energy Density for Supercapacitors 下载免费PDF全文
Xiaoliang Wu Lili Jiang Conglai Long Tong Wei Zhuangjun Fan 《Advanced functional materials》2015,25(11):1648-1655
Layered double hydroxides (LDHs) are promising supercapacitor electrode materials due to their high specific capacitances. However, their electrochemical performances such as rate performance and energy density at a high current density, are rather poor. Accordingly, a facile strategy is demonstrated for the synthesis of the integrated porous Co–Al hydroxide nanosheets (named as GSP‐LDH) with dual support system using dodecyl sulfate anions and graphene sheets as structural and conductive supports, respectively. Owing to fast ion/electron transport, porous and integrated structure, the GSP‐LDH electrode exhibits remarkably improved electrochemical characteristics such as high specific capacitance (1043 F g?1 at 1 A g?1) and ultra‐high rate performance capability (912 F g?1 at 20 A g?1). Moreover, the assembled sandwiched graphene/porous carbon (SGC)//GSP‐LDH asymmetric supercapacitor delivers a high energy density up to 20.4 Wh kg?1 at a very high power density of 9.3 kW kg?1, higher than those of previously reported asymmetric supercapacitors. The strategy provides a facile and effective method to achieve high rate performance LDH based electrode materials for supercapacitors. 相似文献
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A novel method for fabricating micro‐patterned interdigitated electrodes based on reduced graphene oxide (rGO) and carbon nanotube (CNT) composites for ultra‐high power handling micro‐supercapacitor application is reported. The binder‐free microelectrodes were developed by combining electrostatic spray deposition (ESD) and photolithography lift‐off methods. Without typically used thermal or chemical reduction, GO sheets are readily reduced to rGO during the ESD deposition. Electrochemical measurements show that the in‐plane interdigital design of the microelectrodes is effective in increasing accessibility of electrolyte ions in‐between stacked rGO sheets through an electro‐activation process. Addition of CNTs results in reduced restacking of rGO sheets and improved energy and power density. Cyclic voltammetry (CV) measurements show that the specific capacitance of the micro‐supercapacitor based on rGO–CNT composites is 6.1 mF cm?2 at 0.01 V s?1. At a very high scan rate of 50 V s?1, a specific capacitance of 2.8 mF cm?2 (stack capacitance of 3.1 F cm?3) is recorded, which is an unprecedented performance for supercapacitors. The addition of CNT, electrolyte‐accessible and binder‐free microelectrodes, as well as an interdigitated in‐plane design result in a high‐frequency response of the micro‐supercapacitors with resistive‐capacitive time constants as low as 4.8 ms. These characteristics suggest that interdigitated rGO–CNT composite electrodes are promising for on‐chip energy storage application with high power demands. 相似文献
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Energy Storage: Dual Support System Ensuring Porous Co–Al Hydroxide Nanosheets with Ultrahigh Rate Performance and High Energy Density for Supercapacitors (Adv. Funct. Mater. 11/2015) 下载免费PDF全文
Xiaoliang Wu Lili Jiang Conglai Long Tong Wei Zhuangjun Fan 《Advanced functional materials》2015,25(11):1763-1763
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Zhen Chen Huu-Dat Nguyen Maider Zarrabeitia Hai-Peng Liang Dorin Geiger Jae-Kwang Kim Ute Kaiser Stefano Passerini Cristina Iojoiu Dominic Bresser 《Advanced functional materials》2021,31(41):2105343
High-energy Ni-rich lithium transition metal oxides such as Li[Ni0.8Co0.1Mn0.1]O2 (NCM811) are appealing positive electrode materials for next-generation lithium batteries. However, the high sensitivity toward moist air during storage and the high reactivity with common organic electrolytes, especially at elevated temperatures, are hindering their commercial use. Herein, an effective strategy is reported to overcome these issues by coating the NCM811 particles with a lithium phosphonate functionalized poly(aryl ether sulfone). The application of this coating allows for a substantial reduction of lithium-based surface impurities (e.g., LiOH, Li2CO3) and, generally, the suppression of detrimental side reactions upon both storage and cycling. As a result, the coated NCM811-based cathodes reveal superior Coulombic efficiency and cycling stability at ambient and, particularly, at elevated temperatures up to 60 ° C (a temperature at which the non-coated NCM811 electrodes rapidly fail) owing to the formation of a stable cathode electrolyte interphase with enhanced Li+ transport kinetics and the well-retained layered crystal structure. These results render the herein presented coating strategy generally applicable for high-performance lithium battery cathodes. 相似文献
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Jaeyoung Jang Sooji Nam Dae Sung Chung Se Hyun Kim Won Min Yun Chan Eon Park 《Advanced functional materials》2010,20(16):2611-2618
A novel application of ethylene‐norbornene cyclic olefin copolymers (COC) as gate dielectric layers in organic field‐effect transistors (OFETs) that require thermal annealing as a strategy for improving the OFET performance and stability is reported. The thermally‐treated N,N′‐ditridecyl perylene diimide (PTCDI‐C13)‐based n‐type FETs using a COC/SiO2 gate dielectric show remarkably enhanced atmospheric performance and stability. The COC gate dielectric layer displays a hydrophobic surface (water contact angle = 95° ± 1°) and high thermal stability (glass transition temperature = 181 °C) without producing crosslinking. After thermal annealing, the crystallinity improves and the grain size of PTCDI‐C13 domains grown on the COC/SiO2 gate dielectric increases significantly. The resulting n‐type FETs exhibit high atmospheric field‐effect mobilities, up to 0.90 cm2 V?1 s?1 in the 20 V saturation regime and long‐term stability with respect to H2O/O2 degradation, hysteresis, or sweep‐stress over 110 days. By integrating the n‐type FETs with p‐type pentacene‐based FETs in a single device, high performance organic complementary inverters that exhibit high gain (exceeding 45 in ambient air) are realized. 相似文献
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Jaeyoung Jang Sooji Nam Dae Sung Chung Se Hyun Kim Won Min Yun Chan Eon Park 《Advanced functional materials》2010,20(16)
A novel application of ethylene‐norbornene cyclic olefin copolymers (COC) as gate dielectric layers in organic field‐effect transistors (OFETs) that require thermal annealing as a strategy for improving the OFET performance and stability is reported. The thermally‐treated N,N′‐ditridecyl perylene diimide (PTCDI‐C13)‐based n‐type FETs using a COC/SiO2 gate dielectric show remarkably enhanced atmospheric performance and stability. The COC gate dielectric layer displays a hydrophobic surface (water contact angle = 95° ± 1°) and high thermal stability (glass transition temperature = 181 °C) without producing crosslinking. After thermal annealing, the crystallinity improves and the grain size of PTCDI‐C13 domains grown on the COC/SiO2 gate dielectric increases significantly. The resulting n‐type FETs exhibit high atmospheric field‐effect mobilities, up to 0.90 cm2 V?1 s?1 in the 20 V saturation regime and long‐term stability with respect to H2O/O2 degradation, hysteresis, or sweep‐stress over 110 days. By integrating the n‐type FETs with p‐type pentacene‐based FETs in a single device, high performance organic complementary inverters that exhibit high gain (exceeding 45 in ambient air) are realized. 相似文献