【作者】 孙敏；

【导师】 谢腾峰；

【作者基本信息】 吉林大学 ， 物理化学， 2024， 硕士

【摘要】 随着现代生活和工业生产对能源需求的增加以及对环境保护的迫切需求,越来越多的研究者致力于寻求新的经济、高效、清洁、安全的能源和具有更高容量的储能设备。超级电容器作为新一代储能装置表现出了巨大的潜力,其具有高功率密度、长循环寿命和快速充放电的特点,在各个领域得到了广泛的应用。α-MoO3因其在水性和非水性电解质中极高的理论比电容(1117 mAh·g-1)和出色的电化学活性而备受赞誉。此外,它的类石墨层状结构和负的氧化还原电位为Li+提供了理想的插入和迁出通道和位置,使得α-MoO3成为了超级电容器电极的热门候选材料之一。然而,在实际储能应用中,Li+扩散效率的缓慢限制了 α-MoO3的进一步发展。为解决这一问题,本研究首先合成了纳米级电极材料,以缩短电子传输路径,改善Li+传输动力。随后,通过构建异质结,界面产生的导带能级驱动,进一步提高Li+扩散效率。此外,光催化技术在储能装置中也展现了巨大的潜力,通过利用光伏效应产生的非平衡载流子,可以推动氧化还原反应,进一步提高Li+扩散动效率并实现太阳能的储存。以此为基础,同时构建了原位光充能源电池并探究其储能性能和光电转化效率。主要工作如下:(1)以FTO为基底,采用水热方法制备了 α-MoO3纳米片,并利用电化学测试手段明确了其赝电容行为和储能机制。结果表明,在0.1 mA·cm-2的电流密度下,α-MoO3比电容值可高达623.64 F·g-1。为进一步探究其储能性能,选择PPy作为对电极,成功构建了 2.0 V MoO3//PPy非对称的超级电容器,且在0.2 mA·cm-2的电流密度下获得了 25.9 Wh·kg-1的高能量密度和1538 W·kg-1的高功率密度。经过速率测试后,能量密度恢复到了原始容量的91.04%。(2)为进一步提高Li+的扩散效率,通过构建TiO2/MoO3异质结构,利用界面能级差异的驱动以促进界面电荷转移,降低电荷转移电阻。除此之外,异质结的构建缓解了充放电过程中产生了体积膨胀,提高了电极材料的结构稳定性。进一步构建的TiO2/MoO3//PPy超级电容器体系其储能性质也得到了显著提升,在0.1 mA·cm-2的电流密度下获得了 42.28 Wh·kg-1更高的能量密度,是MoO3//PPy相同条件下的产生的能量密度(26.26Wh·kg-1)的1.57倍。(3)采用简单的水浴浸泡的方法,制备了兼具光电转化和原位能量储存的TiO2/MoO3/N3光阳极,通过CV等电化学测试手段验证了光电催化共同作用下Li+扩散效率的进一步提高。另外以Pt为阴极,LiI为主要的氧化还原介质,构建的类DSSCs体系的TiO2/MoO3/N3//I-/I3-/Pt光充储能电池实现了在零偏压光照条件下太阳能的转化与储存。经计算,TiO2/MoO3/N3//I-/I3-/Pt体系在10μA·cm-2的恒定电流下最高的放电时长为724.7 s,相比于MoO3/N3//I-/I3-/Pt电极放电容量(259.3 s)提高了约2.8倍。最后,我们又通过J-V曲线探究了光充能源电池的转化效率,TiO2/MoO3/N3//I-/I3-/Pt体系表现出了 7.72 mA·cm-2的短路电路、0.53 V的开路电压,其光电转化效率为1.80%。更多还原

【Abstract】 Driven by the growing energy demand in modern life and industrial production,accompanied by the urgent need for environmental protection,an increasing number of researchers are dedicated to seeking new,cost-effective,efficient,clean,and safe energy sources and higher-capacity energy storage devices.With their high power density,long cycle life,and rapid charge-discharge characteristics,supercapacitors have emerged as a highly promising energy storage solution of the next generation.These versatile devices have found extensive applications across various domains.αMoO3 has gained considerable acclaim due to its exceptionally high theoretical specific capacitance(1117 mAh·g-1)and outstanding electrochemical activity in both aqueous and non-aqueous electrolytes.Furthermore,its graphite-like layered structure and negative redox potential provide an ideal pathway and site for the insertion and extraction of Li+,making α-MoO3 a promising electrode material with extensive potential applications in energy storage devices.However,the slow kinetics of Li+diffusion in practical energy storage applications have hindered the further development of α-MoO3.To address this issue,in this study,we initially synthesized nanoscale electrode materials to shorten the electron transport pathway and improve Li+transport kinetics.Subsequently,by constructing heterogeneous interface junctions,the differentiated interface energy level structure facilitated interface electron transfer,further enhancing the efficiency of Li+diffusion.In addition,photocatalysis technology has also demonstrated significant potential in energy storage devices.By harnessing the photovoltaic effect to generate non-equilibrium charge carriers,it is possible to drive redox reactions,further enhancing the efficiency of Li+diffusion and enabling the storage of solar energy.Building upon this foundation,an in situ photo-rechargeable energy cell was concurrently developed to investigate its energy storage performance and photoelectric conversion efficiency.The main work of this article is as follows:(1)α-MoO3 electrode materials were prepared using a hydrothermal method on FTO substrates,and their pseudocapacitive behavior and energy storage mechanisms were elucidated through electrochemical testing.The results revealed that at 0.1 mA·cm-2,α-MoO3 exhibited a specific capacitance value of up to 623.64 F·g-1.To further investigate its energy storage performance,PPy was chosen as the counter electrode,leading to the successful construction of a 2.0 V MoO3//PPy asymmetric supercapacitor,which achieved a high energy density of 25.9 Wh·kg-1 and a highpower density of 1538 W·kg-1 at 0.2 mA·cm-2.After rate testing,the energy density recovered to 91.04%of its original capacity.(2)To further enhance the diffusion efficiency of Li+,a TiO2/MoO3 heterostructure was constructed to leverage the interface energy level difference and facilitate interface charge transfer,thereby reducing the charge transfer resistance.Moreover,the construction of the heterojunction alleviated volume expansion during charge-discharge processes,thereby improving the structural stability of the electrode material.Furthermore,the TiO2/MoO3//PPy supercapacitor system exhibited significantly improved energy storage properties.It achieved a higher energy density of 42.28 Wh·kg-1 at 0.1 mA·cm-2,which is 1.57 times higher than the energy density(26.26 Wh·kg-1)obtained under the same conditions for the MoO3//PPy system.(3)A TiO2/MoO3/N3 photoanode was fabricated using a simple immersion method in a water bath,enabling simultaneous photoelectric conversion and in-situ energy storage.Electrochemical tests,including cyclic voltammetry(CV),were performed to confirm the enhanced Li+diffusion kinetics resulting from the combined effects of light and electricity.Furthermore,a TiO2/MoO3/N3//I-I3-/Pt light-charging energy cell,resembling a Dye-Sensitized Solar Cell(DSSC)system,was constructed with Pt as the cathode and LiI as the primary redox mediator.This system facilitated the conversion and storage of solar energy under zero bias voltage and illumination conditions.Calculation analysis revealed that the TiO2/MoO3/N3//I-I3-/Pt system exhibited an extended discharge duration of 724.7 s at a constant current of 10 μA·cm2,demonstrating a remarkable improvement of approximately 2.8 times compared to the discharge capacity of the MoO3/N3//I-/I3-/Pt electrode(259.3 s).Finally,the photoconversion efficiency of the light-charging energy cell was evaluated using J-V(current-voltage)curves.The TiO2/MoO3/N3//I-/I3-/Pt system displayed a short-circuit current of 7.72 mA·cm-2 and an open-circuit voltage of 0.53 V,resulting in an impressive photoelectric conversion efficiency of 1.8%.更多还原