物理化学学报 >> 2022, Vol. 38 >> Issue (1): 2012091.doi: 10.3866/PKU.WHXB202012091

所属专题: 石墨烯的功能与应用

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高结构稳定性、低泄漏率三维铜@石墨烯复合相变材料的制备

李晓明1, 高逸丹1, 孔庆强1, 谢莉婧1, 刘卓1, 郭晓倩1, 刘燕珍1, 卫贤贤3, 杨晓1, 张兴华1, 陈成猛1,2,*()   

  1. 1 中国科学院山西煤炭化学研究所,中国科学院炭材料重点实验室,太原 030001
    2 中国科学院大学材料科学与光电技术学院,北京 100049
    3 太原科技大学环境与安全学院,太原 030024
  • 收稿日期:2020-12-31 录用日期:2021-02-18 发布日期:2021-02-25
  • 通讯作者: 陈成猛 E-mail:ccm@sxicc.ac.cn
  • 作者简介:第一联系人:

    These authors contributed equally to this work.

  • 基金资助:
    国家自然科学基金(21922815);国家自然科学基金(51802325);山西省自然科学基金(201901D211585);山西省科技攻关专项(20191102003);山西省专利推广实施资助专项(20200716);山西省重点研发项目(201903D121007)

Fabrication of Three-Dimensional Copper@Graphene Phase Change Composite with High Structural Stability and Low Leakage Rate

Xiaoming Li1, Yidan Gao1, Qingqiang Kong1, Lijing Xie1, Zhuo liu1, Xiaoqian Guo1, Yanzhen Liu1, Xianxian Wei3, Xiao Yang1, Xinghua Zhang1, Chengmeng Chen1,2,*()   

  1. 1 Key Laboratory of Carbon Materials, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, China
    2 College of Materials Sciences and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing 100049, China
    3 College of Environment and Safety, Taiyuan University of Science and Technology, Taiyuan 030024, China
  • Received:2020-12-31 Accepted:2021-02-18 Published:2021-02-25
  • Contact: Chengmeng Chen E-mail:ccm@sxicc.ac.cn
  • About author:Chengmeng Chen. Email: ccm@sxicc.ac.cn; Tel.: +86-351-404-9061
  • Supported by:
    the National Natural Science Foundation of China(21922815);the National Natural Science Foundation of China(51802325);the Natural Science Foundation of Shanxi Province(201901D211585);the Scientific and Technological Key Project of Shanxi Province(20191102003);the Patent Promotion and Implementation Project of Shanxi Province(20200716);the Key Research and Development (R&D) Projects of Shanxi Province(201903D121007)

摘要:

由于能源消费需求的持续增长和传统化学燃料的日益枯竭,对可再生能源的需求日益迫切。以地热能、太阳能为代表的可再生能源脱颖而出。然而,这些能源的应用易受到天气、季节、地点和时间的影响,具有不稳定性、随机性、波动性和间歇性。储能技术是解决上述问题的有效途径,它可以在需要的时候储存或释放能量。在各种储能技术可选材料中,相变材料(PCMs)是智能热能管理和便携式热能领域的有力候选者。大多数相变材料都存在导热系数低、环境污染、熔点泄漏等问题,因此有必要将相变材料封装到支撑骨架材料中。事实上,支撑材料在应用中仍面临着一些重大挑战。首先,骨架材料应能抵抗相变材料在相变过程中的体积变化,即具有良好的结构稳定性。其次,还应具有较高的导热系数和较低的泄漏率。石墨烯气凝胶(GA)已被证明是提高相变材料形状稳定性的有效支撑骨架,但相变引起的泄漏和网络结构的脆性是制约其应用的关键问题。在此,我们提出了一种双脉冲电镀的强化策略,用于制备铜@石墨烯气凝胶(Cu@GA)作为相变储能骨架材料。这一结构设计中,石墨烯气凝胶上的石墨烯片层上均匀地镀上了铜层,且不同片之间被铜镀层所连接。这种铜增强石墨烯气凝胶网络结构赋予复合材料良好的导热性和坚固的骨架稳定性,有利于增强相变换热和抑制相变过程中的泄漏。此外,通过真空浸渍法将十八胺(ODA)封装在Cu@GA骨架中,获得了结构稳定性高、泄漏率低的复合相变材料(Cu@GA/ODA),保证了ODA在Cu@GA骨架材料中的均匀分散和填充。通过比较复合相变材料的重量变化,研究了不同骨架对复合相变材料泄漏率的影响。优化后的复合相变材料(CPCM)Cu@GA/ODA经20次储热、放热循环后,泄漏率降低至19.82% (w,质量分数),而GA/ODA和GOA/ODA为骨架的复合相变材料的泄漏率分别为80.31% (w)和72.99% (w)。为了探讨这种影响的原因,用扫描电子显微镜(SEM)观察了循环后骨架的形貌。铜/石墨烯气凝胶(Cu@GA)骨架材料没有明显的收缩或坍塌,仍可以保持完整的三维网络结构,而氧化石墨烯气凝胶(GOA)和石墨烯气凝胶(GA)的骨架材料三维结构不复存在,且在氧化石墨烯/石墨烯片能够观察到明显的裂隙。铜涂层可以提高骨架的微观结构稳定性,有利于提高结构稳定性,降低复合材料的泄漏率。同时,该研究为构建理想的金属增强石墨烯气凝胶复合骨架材料铺平了新的道路,该复合材料具有优异的综合性能,可用于未来的相变储能、多孔微波吸收和储能应用。

关键词: 电镀, 铜/石墨烯气凝胶, 三维石墨烯骨架, 相变材料, 脆性

Abstract:

Owing to the continuous increase in energy consumption and the growing depletion of traditional fossil fuels, the development of renewable energy is becoming increasingly urgent. Renewable energy has come to the fore, represented by geothermal energy and solar energy. However, the application of these energy sources is highly susceptible to weather, season, location, and time. Thus, these alternative energies are unstable, random, fluctuating, intermittent, and inefficient. The development of energy storage technologies can efficiently solve these problems, storing and releasing energy when needed. Among the key materials used in various energy-storage technologies, phase-change materials (PCMs) are strong candidates for smart thermal energy management and portable thermal energy sectors. As most innate PCMs face issues of low thermal conductivity, environmental pollution, and leakage over their melting point, encapsulating PCMs into supporting materials is necessary. However, these supporting materials face significant challenges in their application. First, skeleton materials should be resistant to the PCM volume changes during melting and solidification processes to achieve suitable structural stability. Second, skeleton materials should also have high thermal conductivity and a low leakage rate. Graphene aerogel (GA) has proven to be an effective supporting skeleton to improve the shape-stability of PCMs; however, the leakage caused by the phase transition and the brittleness of the network structure is a primary problem restricting its application. Skeleton materials play a crucial role in the performance of PCMs. Herein, we propose a double-pulse plating reinforcement strategy for fabricating copper@graphene aerogel (Cu@GA) as a skeleton material for phase change energy. In this design, individual nanosheets of the GA were uniformly covered and interlinked by copper particles. The Cu@GA interlinked networks ensure suitable thermal conductivity and a robust framework, beneficial for phase change heat transfer and leak-suppression performance. In addition, we prepared a PCM composite with high structural stability and low leakage rate by encapsulating octadecylamine (ODA) in Cu@GA through vacuum impregnation to ensure homogeneous ODA dispersion in the Cu@GA porous structure. The influence of different skeletons on the PCM composite leakage rate was investigated by comparing the weight change of the PCM composite. Benefiting from these structural features, the optimized composite phase change material (CPCM) Cu@GA/ODA showed a reduced leakage rate of 19.82% (w, mass fraction) compared to 80.31% (w) of GA/ODA and 72.99% (w) of GOA/ODA after 20 heat storage and release cycles. The cycled skeleton morphology was investigated using scanning electron microscopy to determine the origin of this influence. The skeleton integrity of Cu@GA/ODA was well maintained, while the three-dimensional network structures of GOA/ODA and GA/ODA showed shrinkage or collapse. Thus, the copper coating increased the skeleton's microstructural stability, conducive to high structural stability and reducing the leakage rate of the PCM composite. This study paves the way for the construction of ideal metal-coating GA composites with an excellent comprehensive performance for future phase change energy storage, porous microwave absorption, and energy storage applications.

Key words: Electroplating, Copper@graphene aerogel, 3D graphene skeleton, Phase change material, Friability

MSC2000: 

  • O642