新型快速充放纳米热储存复合材料的构筑与性能研究

To better utilize the renewable solar energy and overcome the shortcoming of slow charging and discharging rate for the conventional thermal diffusion based organic thermal energy storage materials, a novel solar energy storage nanocomposite based on photothermal effect of metallic nanoparticles (NPs) is proposed by this program. Surfaced modified metallic NPs will be incorporated into silicone oil (a sensible thermal storage material) to develop the solar energy thermal storage materials with fast charging and discharge rates. The compatibility between NPs and silicone oil matrix will be improved by modifying the NP surfaces with bimodal long and short grafted matrix compatible chains. The dispersion state and self-assembly mechanism of the grafted NPs with different sizes and morphologies within the matrix will be systematically studied, thereby enabling the preparation of the composites with the best solar absorption performances. Thermal infrared camera, thermal couple and thermal atomic force microscopy (AFM) will be used to study the photothermal conversion behavior of the prepared composites and to measure the energy storage efficiency as well as investigate the energy storage mechanism of the nanocomposites. Surface modified high thermal conductivity NPs will be introduced to form thermal conduction path within the matrix and to improve the discharging rate of the nanocomposites. Finally, the chemical compositions and preparation parameters will be optimized to fabricate the high-efficiency solar harvesting thermal storage nanocomposites with fast charging and discharging rates.

为提高对可再生能源太阳能的利用效率和克服传统基于热传导机制的有机热储存材料充放热速率慢的缺点，本项目拟通过向有机硅油储热材料中添加表面修饰的金属纳米粒子并调控其自组装和分散状态，开发基于金属纳米粒子光热效应的能快速充放热的新型太阳能热储存复合材料。通过在金属纳米粒子表面嫁接混合的长短链，提高其与有机硅油基体相容性，并通过改变表面修饰结构和参数来研究不同形貌不同尺寸的金属纳米粒子在有机硅油中的自组装机理，制备出能最大程度吸收太阳光的复合材料。利用红外相机、热电偶和扫描热原子力显微镜等手段研究纳米热储存材料在不同尺度上的光热转换行为，测量复合材料的热储存效率，揭示复合材料的热储存机制。通过向复合材料体系中引入高导热率纳米粒子并在基体内形成导热通道，提高复合材料放热速率。通过优化复合材料的参数和工艺，制备出能快速充放热的高效太阳能热储存复合材料。

太阳能热储存能克服太阳光照间歇性、能量密度低等缺点，是发展和利用高效太阳能光热技术的关键。当前太阳能热储存依靠从集热涂层向储热材料的热传导方式进行储热。然而，储热材料的低导热率严重地限制了热储存速率。本项目提出了基于纳米材料光热转换效应的直接太阳能光热储存，大幅提升了太阳能光热储存的速率，而且最大程度地保留了储热材料优良的物理性能，包括储热容量、流动性、加工性等。我们开发了一整套方案成功地制备了能够稳定分散的硅油基纳米储热流体，实现了110摄氏度下稳定的太阳能光热储存。进一步地，我们通过制备兼具磁响应和光热转换的四氧化三铁-石墨烯复合光热材料与有机石蜡进行复合，通过引入外加磁场调控纳米材料的动态分布，进一步加快了太阳能光热储存速率。通过物理建模，全面地揭示了新型储热的物理机制，分析了影响储热性能的因素。此外，本项目还探索了基于界面蒸发的高效太阳能光热利用，应用于海水淡化、污水净化等领域，制备了基于气液相变的热能传输装置，为将来构建高效太阳能光热利用系统奠定基础。