H2S气体浓度及流率对复合质子传导膜燃料电池性能的影响

采用溶胶—凝胶法制备了纳米级Li2SO4+Li2WO4+Al2O3复合质子传导膜，研究了不同H2S气体浓度、流率和操作温度对结构为H2S、（复合MoS2阳极催化剂）/ 复合质子传导膜/（复合NiO阴极催化剂）、空气的燃料电池电化学性能影响。燃料电池的性能与通入阳极侧的H2S浓度和流率有关，H2S浓度和流率增加，提高了阳极侧气体扩散速率和电化学活性组分，使燃料电池的开路电压、输出电流与功率密度提高，电化学性能变好。即使气体中的H2S浓度低达5%时，该气体也可作为电池的燃料并用来发电。操作温度增加，质子传导膜的电传导率和电化学反应速率增加，电池的输出电流与功率密度提高。比较了MoS2与复合MoS2催化剂的性能，复合MoS2催化剂比MoS2催化剂具有更好的性能和化学稳定性。当采用纯H2S作为燃料，通入阳极和阴极侧的H2S和空气的流率分别为35ml?min-1和100ml?min-1，操作温度为650、700和750oC时，燃料电池产生的最大功率密度为12.4、52.9和130 mW?cm-2、最大电流密度为45、281和350 mA?cm-2。

Influence of H2S Concentration and Flow Rate in Gas Mixture on Performance of Composite Proton Conducting Membrane Fuel Cells

Nano-composite proton conducting membrane of Li2SO4+Li2WO4+Al2O3 for H2S solid oxide fuel cells was preparaed by a gel-solution method. Influence of various H2S concentraions and flow rates in gas mixture as well as operating temperature on electrochemical performance of fuel cell having the configuration of H2S, (composite MoS2 anode catalyst)/composite proton conducting membrane/ (composite NiO cathode catalyst), air was investigated. Performance of the fuel cell was related with H2S concentraion and flow rate entering anode compartment. The open circuit voltage, current and power densities increased with increasing both H2S concentraion and flow rate in gas mixture. This is attributed to improved gas diffusion in anode and increased concentration of anodic electroactive species, and is resulted in imporved electrochemical performance of the fuel cell. However, as low as 5% H2S concentraion in gas mixture can also be used as fuel feed to cells to produce the power. Electrochemical reation rate and ion conductivity (electric conduction) of proton-conducting membranes increased with the temperature, and cell performance became better with increasing cell operation temperature. The results of composite MoS2 anode catalyst was compared with those of MoS2 anode catalyst, and the former had superior performance and better chemical stability in H2S stream. When pure H2S flow rate of 35ml?min-1 entering the anode compartment and air flow rate of 100ml?min-1 entering the cathode compartment were utilized, a fuel cell produced the maximum power densities up to 12.4、52.9 and 130 mW?cm–2, and the maximun current density 45, 281 and 350 mA?cm–2 were achieved at 650, 700 and 750°C, respectively.