基于纳米多孔铜@氧化亚铜的光辅助充电超级电容器研究

After fossil energy, the solar energy has been considered as one of the most promising alternative. Solar cell can convert solar energy into electrical energy to use directly, whereas it is not able to store the electrical energy. Supercapacitor is considered as a promising candidate for energy storage because it has the advantages of higher power densities and a short charging time and so on. How to combine the solar energy conversion with energy storage to realize the direct storage of solar energy is very important to solve. Herein, a photoassisted rechargeable supercapacitor has been designed and fabricated. The NPC@Cu2O photo-electrode which possess photosensitive and supercapacitor properties provides the possibility of the construction of the photoassisted rechargeable supercapacitor. The photoassisted rechargeable supercapacitor has the advantages of the solar cells and supercapacitor, which can realize the direct storage of solar energy. Thus, a highly conductive and free-standing core-shell NPC@Cu2O electrode is fabricated through that: a three-dimensional (3D) nanoporous copper (NPC) is synthesized via free-dealloying the ductile Cu-based metallic glasses and then self-oxidized to form in-situ heterogenous NPC@Cu2O. The morphology and structure of the NPC@Cu2O hybrids can be controlled by adjusting the precursor alloy composition, dealloying conditions and self-oxidized process and so on. The relationship between the morphology, structure and the photoassisted rechargeable supercapacitor performances of the NPC@Cu2O hybrids has been investigated from microscopic level. We will also elucidate the coupling mechanism among NPC@Cu2O hybrids, the nanosize effects on improving the photoassisted rechargeable supercapacitor properties of the electrode material, and the photo-electrochemical mechanism, so as to propose the energy storage model and mechanism of the NPC@Cu2O hybrids. The success of this project will provide theoretical guidance and the technical approach for the research and development of photoassisted rechargeable supercapacitor.

继化石能源之后,太阳能被认为是最有希望的替代能源之一。太阳能电池可以将太阳能转换成电能直接使用,然而不能实现能量的存储。超级电容器具有充放电速度快、功率密度高等优点，是一种非常有潜力的能量存储装置。如何将太阳能电池和超级电容器有效结合起来实现光能的直接存储成为亟待解决的问题。本项目设计构筑了一种光辅助充电超级电容器,该器件以兼具光敏性能和电容性能的纳米多孔铜@氧化亚铜作为复合电极，从而实现光能的直接存储。采用脱合金的方法合成三维纳米多孔铜(NPC)，然后通过表面化学修饰生成具有异质核壳结构的NPC@Cu2O复合材料。通过合理调节合金成分、脱合金技术参数、自氧化过程等条件，实现复合电极材料形貌和结构的调控。从微观层次上研究NPC@Cu2O的结构与光辅助充电超级电容器性能的关系，阐明光辅助充电超级电容器的储能机理。本项目的实施有助于为光辅助充电超级电容器的研发提供理论依据和和技术途径。

氧化亚铜（Cu2O）用作光电极材料，具有较窄的禁带宽度（2.2 eV），良好的化学稳定性、价格低廉等，但是其较短的光生空穴传输距离、光生载流子的寿命、较差的Cu2O表面稳定性，导致其较低的太阳能利用率和较差的储能性能，阻碍其大规模应用。本项目针对Cu2O上述的缺点，设计制备了：i)兼具光敏性能和电容性能的纳米多孔铜@氧化亚铜（NPC@Cu2O）复合材料；ii)过渡金属硫化物修饰的NPC@Cu2O复合光电极材料；iii)过渡金属磷化物修饰的NPC@Cu2O复合光电极材料；iv)几类不同的过渡金属化合物光电极材料。该研究采用XRD、XPS、SEM、Raman、TEM等结构表征，并结合相关的光电化学表征手段，得出下面的结论：i)解释了NPC@Cu2O复合光电极材料的性能优化机理；ii)将过渡金属硫化物、磷化物与Cu2O光电极耦合，改善了光电化学性能，并证明了其性能耦合机理；iii)多相异质结对Cu2O光电化学储能性能的改善作用被初次证实；iv)对比了几类不同纳米结构的光电复合电极材料，证实电化学活化可以显著改善NPC@Cu2O的光电化学性能。上述结论阐述了光电复合电极材料的微纳结构与电化学性能之间的关系，解释了其性能耦合机理、光电化学性能改善机理和光电化学储能机理，为高性能光电极材料的开发和研究奠定了坚实的理论基础。