Silicon-based micro direct methanol fuel cell with an N-inputs-N-outputs anode flow pattern

A micro direct methanol fuel cell(μDMFC) is suitable for use in notebook computers,mobile phones,and other digital products.To resolve the poor mass-transport efficiency problem in the anode flow channel,this paper presents an N-inputs-N-outputs parallel flow pattern with rectangular convexes to reinforce methanol mass transport and reduce concentration polarization.The simulation results show that the N-inputs-N-outputs parallel flow channels with the rectangle convexes improve the performance.μDMFCs,which have four anode flow patterns,are fabricated using MEMS(microelectromechanical systems) technology.The experimental results show that the μDMFC with the rectangle convexes has a performance better than previously reported systems,and has a peak power density of 19.96 mW/cm2.The simulation and experimental results are in good agreement.     

Bi掺杂的直接甲醇燃料电池阳极催化剂研究进展

发展可替代能源对缓解全球能源问题具有重要意义。直接甲醇燃料电池(direct methanol fuel cell,DMFC) 因其工作温度低、能量密度高以及污染物排放少等特性,正逐渐成为最有发展前景的便携式能源技术之一。目前,其商业化进程主要取决于甲醇氧化反应(methanol oxidation reaction,MOR) 的动力学快慢、催化剂的成本和寿命。Bi元素的掺杂可以极大地提高甲醇电催化氧化的性能,并且可以提高阳极催化剂抵抗CO中毒的能力。介绍了掺杂Bi的贵金属和非贵金属阳极电催化剂,以及贵金属掺杂Bi₂O₃、Bi₂WO₆ 等光辅助电催化剂;综述了它们提高甲醇电催化氧化性能的机制,并展望了阳极Bi电催化剂在DMFC中所面临的机遇和挑战。     

直接甲醇燃料电池的阳极进料系统及控制策略

直接甲醇燃料电池(direct methanol fuel cells,DMFC)的甲醇燃料的利用关系到系统的能量密度,是其微型化亟待解决的问题。为了提高甲醇利用率和提高系统的能量密度,必须采用必要的进料系统和控制策略。该文从主动和被动两类系统总结了面向直接甲醇燃料电池的关键系统组件和相关的控制策略,从系统工程的角度加以分析,总结了DMFC用甲醇传感器和系统控制的设计开发思想,并指出电池型化学传感器将是DMFC用甲醇传感器的主要开发方向,系统需采用脉冲式进料和混合动力方式以适应不同模式的负载。自呼吸电堆需采用基于化学势为推动力的被动式进料方式。采用空载自升温模式有助于缩短启动时间。     

Three-dimensional ordered macroporous platinum-based electrode for methanol oxidation

The attractive application of the direct oxidation methanol fuel cell (DMFC) in wide application areas, such as portable energy and stationary power suppliers, stimulates researchers to search for optimal anodic electrocatalysts for the oxidation of methanol. In prac- tical performance, the catalysts are generally dispersed as nanoparticles for conducting supports with high sur- face area for obtaining maximum catalyst utilization. Porous carbon is one of the well-known supports for the dispe…     

Electrostatic self-assembly Pd particles on Nafion^TM membrane surface to reduce methanol crossover

Nafion^TM perfluorosulfonate proton exchange membranes (PEM) have been widely used as solid electrolytes in direct methanol fuel cell (DMFC) because it possesses relatively good mechanical strength and chemical stability.Due to its structure of side chains (-SO3ˉ) fixed at CF backbones, phase separation occurs between hydrophilic regions and hydrophobic ones in hydrated Nafion^TM membrane.     

Micro PEM Fuel Cells and Stacks

1 Results The effects of different operating parameters on micro proton exchange membrane (PEM) fuel cell performance were experimentally studied for three different flow field configurations (interdigitated,mesh,and serpentine).Experiments with different cell operating temperatures and different backpressures on the H2 flow channels,as well as various combinations of these parameters,have been conducted for three different flow geometries.The micro PEM fuel cells were designed and fabricated in-house through a deep UV lithography technique and the SU-8 photoresist was used as microstructure material for the fuel cell flow field plates.Results are presented in the form of polarization VI curves and PI curves under different operating conditions.The possible transport mechanisms associated with the parametric effects were discussed.Moreover,it was found that among the three flow patterns considered,significant improvements can be reached with a specified flow geometry.     

Electrochemical characterization of the Pt /PEDOT electrode in DMFC

Poly-(3, 4-ethylenedioxythiophene) (PEDOT) was applied in making electrodes and gas diffusion layer for direct methanol fuel cells (DMFC). Electrochemical characterizations of Pt/PEDOT electrodes, made by two different methods, were investigated by cyclic voltammetry, methanol oxidation tests and DMFC performance. The platinum particle structure in PEDOT/PSS (poly?styrene sulfonic acid) films was investigated by SEM and TEM. Our research work showed that PEDOT influenced the catalytic activity behavior in three different ways when it was applied to the anode, cathode and the gas diffusion layer. The DMFC performance agreed with the cyclic voltammetry and methanol oxidation test results.     

基于模糊辨识的燃料电池建模

通过分析直接甲醇燃料电池(DMFC)的组成结构、工作原理，运用电化学、流体动力学、热力学等学科理论，建立DMFC电池性能数学模型，并根据DMFC实验数据进行了仿真。由于数学模型具有复杂性，难以满足工程上对DMFC控制系统的设计，特别是实时控制需要的情况，因此采用一种基于在线辨识的模糊预测算法对DMFC电堆进行建模。结果表明，这种数学建模是合理和可行的，对直接甲醇燃料电池控制系统的建模和控制具有一定的实用价值。     

Highly efficient anode catalyst with a Ni@PdPt core–shell nanostructure for methanol electrooxidation in alkaline media

To enhance the electrocatalytic activity of anode catalysts used in alkaline-media direct methanol fuel cells (DMFCs), a Ni@PdPt electrocatalyst was successfully prepared using a three-phase-transfer method. The Ni@PdPt electrocatalyst was characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and high-resolution TEM (HRTEM) techniques. The experimental results indicate that the average particle size of the core–shell-structured Ni@PdPt electrocatalyst is approximately 5.6 nm. The Ni@PdPt electrocatalyst exhibits a catalytic activity 3.36 times greater than that of PdPt alloys for methanol oxidation in alkaline media. The developed Ni@PdPt electrocatalyst offers a promising alternative as a highly electrocatalytically active anode catalyst for alkaline DMFCs.     

微型直接甲醇燃料电池流场板内多相流动分析

针对微型直接甲醇燃料电池,运用多孔介质理论建立了微型直接甲醇燃料电池流场板内含电化学反应的、毛细力驱动下的微通道内多相流动的传输模型;计算并分析了流场板内微通道尺寸、功率密度等重要参数对毛细力驱动下微通道中多相流动的传输特性的影响,以及流场板内微通道尺寸对电池性能的影响.结果表明:微通道内液相饱和度随通道宽度和高度的增加而增大,随节距和电池功率密度的增加而减小;电池的功率密度随微通道高度和宽度的增加而增大,随节距和长度的增加而减小.     

Operational and structural aspects of a vapor-feed semi-passive direct methanol fuel cell supplied with concentrated methanol

Direct methanol fuel cell （DMFC） has great potential to replace the traditional battery in the field of portable power sources. This study investigates the operational and structural aspects of a vapor-feed semi-passive DMFC supplied with concentrated methanol. The effec tiveness of using vaporous methanol to improve the cell performance is experimentally validated. Results indicate that there exits an optimal value of methanol concentration that favors both methanol supply and control of methanol crossover （MCO）. With the increase in vaporization temperature, the cell performance can be enhanced. Based on the traditional structural design, a sintered porous metal plate is further used to depress the impact of MCO so that the cell performance can be significantly improved at a relatively higher methanol concentration. This is of great importance to enhance the energy density and operating duration for portable applications. The mechanisms related to the performance behaviors are discussed in detail.     

A New Process and Technology for Rapid Prototyping of A μ-Micro Motor

A new process and technology of rapid prototyping for a μ-micro motor is presented as a nontraditional machining and an advanced manufacturing technology (AMT) to be realized by using masks, including the operation principle of the motor, structure design, technique, driven circuit, and quality examination with Raman spectrum. The μ-micro motor is fabricated by the micro electro-mechanical systems (MEMS) process, the structure design must be considered to fabricate or assembly the parts during machining the motor in the meantime. The research proved that integration of IC (integrated circuit) process and MEMS using masks is effective in obtaining the rapid prototyping manufacturing of the μ-micro motor. With the mature technique to fabricate the motor, there are advantages to produce the motor in short time and with lower cost than before. The motor is a common power source of micro machines in military and civilian applications, for example, applied to micro robot, micro bio medicine, and micro machine. The size of the motor is 190 μm in maximum diameter by 125 μm in height that is bulk machined in array with the number of hundreds of micro motors on a substrate.     

阳极流场结构对直接甲醇燃料电池性能影响研究

直接甲醇燃料电池(DMFC)以其能量密度高、环境友好、结构简单和储存携带方便等优点在便携式产品领域得到广泛关注。流场结构设计是否合理是影响燃料电池输出性能的关键因素之一。本文采用非均衡流场的设计思路,对比了非均衡蛇形流场和均衡蛇形流场的DMFC输出性能。实验结果表明,非均衡蛇形流场结构能够提高DMFC的输出性能,当DMFC水平放置时,非均衡蛇形流场的DMFC峰值功率比均衡蛇形流场的DMFC提高33%左右;均衡蛇形流场的DMFC竖直方式放置时,其输出性能比水平放置时有明显提高,而非均衡蛇形流场的DMFC竖直方式放置时,其输出性能与水平放置时相差不多。     

磺化聚醚醚酮(sPEEK)/SiO2杂化质子交换膜的制备与表征

为提高磺化聚醚醚酮(sPEEK)质子交换膜的耐甲醇渗透性能,用正硅酸乙酯为前驱体制得硅溶胶,在sPEEK中原位生成SiO2,制备了直接甲醇燃料电池用sPEEK/SiO2杂化质子交换膜材料,用核磁共振(1H-NMR)和Fourier红外光谱(FT-IR)表征了膜的化学结构,用扫描电子显微镜(SEM)观察了sPEEK与SiO2的复合形态,用交流阻抗仪和气相色谱仪分别测定了膜的质子传导率和甲醇渗透系数。实验结果表明,在质子传导率没有严重降低的同时,杂化膜的阻醇性得到了较好的改善。     

320×256红外焦平面阵列读出电路的设计

提出了一种320×256红外焦平面阵列读出电路的原理及电路设计,采用直接注入的单元电路,在给定的单元面积内可以获得较大的积分电容。相关的320×256阵列读出电路已经在0.5μm双层多晶三层铝N阱CMOS工艺线上实现,整体芯片的面积为9.0 mm×11.2 mm。实测结果表明芯片在常温和低温77 K时都工作正常,工作频率大于5 MHz,整电路的功耗为48 mW左右,动态范围是75 dB,噪声电压为0.5 mV。     

电动车电池研究进展

采用电动车代替汽车可以彻底根除汽车尾气的污染,开发电动车的核心问题是电池。比较实用的电动车电池有:镍 -金属氢化物 (Ni-MH)蓄电池、金属燃料电池、氢 -氧燃料电池和直接甲醇燃料电池。介绍了这些电池的结构、原理,以及近年来的研究进展和今后的改     

圆形直接甲醇燃料电池阴极涂覆装置的设计

针对圆形直接甲醇燃料电池阴极扩散层及催化层的涂覆现状．结合该电池形状及涂覆特点,设计一种可实现连续、自动涂覆的旋转涂覆装置．阐述了利用电极旋转时所受的力使浆料均匀涂覆在电极支撑体表面的原理．分别给出涂覆装置的传动结构、烘干结构、整体结构设计,并指出设计中需要注意的要点及改进的方向．结果表明,该装置涂覆连续性强,均匀性好,可以在一定程度上减小涂覆的劳动强度与重复强度,提高涂覆效率．     

直接甲醇燃料电池用Co-N-C电催化剂的制备及性能

以三聚氰胺甲醛树脂和硝酸钴为前驱体,在Ar保护下采用高温碳化方法制备用于直接甲醇燃料电池(DMFC)阴极的含氮碳载钴(Co-N-C)氧还原电催化剂.利用热重与红外光谱联用、X射线衍射分析、元素分析等方法表征了催化剂的制备过程和结构,采用旋转圆盘电极测试考察了不同碳化温度对Co-N-C电催化剂氧还原催化活性的影响及电催化剂的耐醇性能,并采用该催化剂为阴极催化剂进行DMFC单电池测试.结果表明:Co-N-C电催化剂具有较高的电催化活性和较好的耐醇性能;其氧还原起始电位在0.5V(vs.SCE)左右;700℃碳化温度下制备的Co-N-C电催化剂具有最高的氧还原催化活性.     

便携式直接甲醇燃料电池

采用超薄无Teflon化催化层制备直接甲醇燃料电池空气电极,用电化学沉积方法制备甲醇氧化催化剂PtRu／C。提出较高电位下甲醇氧化的概念。所研制的直接甲醇燃料电池的催化电极贵金属催化剂的利用率提高,甲醇氧化过程催化剂CO中毒问题能够基本消除。