【作者】 吴锐；

【导师】 叶丁丁；

【作者基本信息】 重庆大学 ， 工程硕士（动力工程）（专业学位）， 2018， 硕士

【摘要】 近年来,随着移动互联网技术的高速发展,便携式电子设备如智能手环、智能手机、智能手表等层出不穷,而传统电池技术发展跟不上市场上便携式电子产品长时间运行而不需频繁充电的实际需求。无膜微流体燃料电池(Membraneless microfluidic fuel cell,MMFC)利用燃料和氧化剂层流流动的特点,不需要隔膜来分离阳极和阴极,消除了传统燃料电池由于膜而产生的相关问题,具有比表面积大、易集成、功率密度高、携带方便等优点,被认为是最有应用前景的微型电源之一,从而受到研究学者的广泛关注。现有的微流体燃料电池大多需要外部驱动设备来维持电池内部燃料和氧化剂的层流流动,降低了电池的净功率输出,限制了其实际应用。本文提出了一种基于纤维的碳纸阳极被动式微流体燃料电池,通过棉线的毛细力辅以重力的作用实现了燃料和氧化剂的被动式运输,取消了微流体燃料电池对外部驱动设备的依赖。从传质的角度对电池阳极和阴极结构进行了改进,构建了纤维一体化阳极以及空气自呼吸阴极被动式微流体燃料电池,系统研究了燃料浓度,电解液浓度以及反应物流量对电池产电特性的影响。本文主要研究成果如下:(1)构建了基于纤维的碳纸阳极被动式微流体燃料电池,采用棉线作为微流体燃料电池的液体输运通道,实现了燃料和氧化剂的被动运输。在燃料和氧化剂之间引入隔离液,有效避免了燃料和氧化剂的扩散混合。结果表明在燃料浓度为2M、电解液浓度为2M,流量为27.33μL/min时,电池最大功率密度和极限电流密度分别为19.9mW/cm~2和111.2mA/cm~2,与文献报道的基于织物的微流体燃料电池相比,最大功率密度提高了3.5倍。(2)采用反复浸渍沉积法在棉线上负载催化剂,制备了纤维一体化阳极,并构建了纤维阳极被动式微流体燃料电池,在燃料浓度为2M、电解液浓度为2M,流量为27.33μL/min时,电池的最大功率密度为21.84 mW/cm~2,极限电流密度为126.82 mA/cm~2。与碳纸阳极的被动式微流体燃料电池相比,有效促进了阳极燃料向电极表面的传质,燃料浓度为0.2M时性能可提升138%,而且比碳纸阳极电池表现出了更好的恒电压放电稳定性。(3)采用空气自呼吸阴极替代溶解氧阴极,结合纤维一体化阳极的优势,构建了纤维一体化阳极-空气自呼吸阴极被动式微流体燃料电池,促进了电池阴极侧在高电流密度区的传质,电池的极限电流密度提高了7%。研究表明,电池性能随燃料浓度和电解液浓度的增加呈现先升高再降低的趋势,随流量的增加性能逐渐提升。更多还原

【Abstract】 In recent years,with the rapid development of mobile Internet technology,more and more portable electronic devices such as smart wristbands,smart phones,and smart watches have emerged.However,the traditional battery technology cannot keep up with the demand for portable electronic products in the market that they do not require frequent charging during long period of operation.The membraneless microfluidic fuel cell(MMFC)utilizes the laminar flow characteristics of the fuel and the oxidant,does not require a membrane to separate the anode and the cathode,and eliminates the problems associated with conventional fuel cell membranes.Due to its advantages such as large specific surface area,easy to integrate,high power density,easy portability,etc.,MMFCs are considered to be one of the most promising miniature power sources and have attracted widespread attention from researchers.At present,most of the microfluidic fuel cells require external drive equipment to maintain laminar flow of fuel and oxidant,reducing the net power output of the fuel cell,further limiting its practical application.In this study,a fiber-based passive microfluidic fuel cell with carbon paper anode was proposed.The fuel and oxidant are transported passively by the capillary force of the cotton thread,and the dependence of the microfluidic fuel cell on the external driving equipment is eliminated.The structure of the anode and cathode of the fuel cell was improved in terms of mass transfer.The passive microfluidic fuel cell with fiber-integrated anode and air-breathing cathode were designed.The effect of the fuel concentration,electrolyte concentration and reactant flow rate on the cell performance were discussed.The main research results of this study are as follows:(1)A fiber-based passive microfluidic fuel cell with carbon paper anode was fabricated.The cotton thread was used as the flow channel of the microfluidic fuel cell to realize the passive transportation of fuel and oxidant.Through adding the third fluid to separate the fuel and the oxidant,the diffusion mixing of the fuel and the oxidant was effectively avoided.It was found that at fuel concentration of 2M,electrolyte concentration of 2M and flow rate of 27.33μL/min,the maximum power density and current density were 19.9 mW/cm~2 and 111.2mA/cm~2,respectively.Compared with the fabric-based microfluidic fuel cell reported before,the performance of the proposed fuel cell in this study was increased by 3.5 times.(2)A fiber-integrated anode was prepared by repetitive dip deposition coating method to fabricate catalyst layer on cotton thread surface.A passive microfluidic fuel cell with fiber-integrated anode was constructed.At fuel concentration of 2M,electrolyte concentration of 2M and flow rate of 27.33μL/min,the maximum power density of the fuel cell was 21.84 mW/cm~2,and the limiting current density was 126.82mA/cm~2.Compared with the microfluidic fuel cell with carbon paper anode,the mass transfer of anode fuel to the electrode surface was effectively promoted,and the performance was increased by 138%at fuel concentration of 0.2 M.More stable performance was found when the fuel cell was discharged at constant voltage.(3)Combining the advantages of air self-breathing cathode and fiber-integrated anode,a passive microfluidic fuel cell with fiber-integrated anode and air-breathing cathode was constructed.It was found that the mass transfer at cathode at high current densities was enhanced,leading to the maximum current density was improved by 7%.Moreover,the cell performance showed a trend of increasing at first and then decreasing with increasing fuel concentration and electrolyte concentration,while increased gradually with an increase in the flow rate.更多还原