亲疏水交替碳纸的制备及其在气体扩散层中的应用

Preparation of hydrophilic and hydrophobic alternating carbon paper and its application in the gas diffusion layer

摘要:

气体扩散层（GDL）作为控制质子交换膜燃料电池（PEMFC）水气传输的核心部件，对PEMFC的性能具有重要影响。将碳纤维纸（CP）浸渍聚四氟乙烯（?PTFE）乳液后，通过模具夹持进行干燥，得到了亲疏水交替的CP，并通过微孔层（MPL）涂敷工艺制备了基底层亲疏水交替的GDL，以期提高PEMFC性能。通过SEM、EDS、接触角、垂直平面（TP）电阻率、垂直平面（TP）透气率和电化学性能等测试对基底层亲疏水交替GDL的结构与性能进行了分析。结果表明：浸渍PTFE乳液的CP经模具夹持干燥后，形成条纹状亲水区和疏水区。将基底层亲疏水交替的GDL组装成单电池，在2 A/cm2电流密度（简称电密）下的电压为0.47 V，功率密度为948 mW/cm2；相同条件下，采用基底层无差别疏水处理的GDL组装成单电池，其电压为0.44 V，功率密度为884 mW/cm2，与基底层无差别疏水处理的GDL相比，电压及功率密度分别提高了6.82%和7.24%。

关键词:气体扩散层;碳纸;亲疏水交替;燃料电池;水管理;功能材料

Abstract:

As the core component of controlling the water vapor transmission of proton exchange membrane fuel cell (PEMFC), gas diffusion layer (GDL) has an important influence on the performance of PEMFC.After soaking the carbon paper (CP) with Polytetrafluoroethylene (PTFE) , the carbon paper treated with alternating hydrophilic and hydrophobic pressing by mold filling was obtained, and the hydrophilic and hydrophobic alternating gas diffusion layer (GDL) was prepared by microporous layer (MPL) coating process, in order to improve the water management ability of proton exchange membrane fuel cell (PEMFC). The structure and performance of hydrophilic and hydrophobic alternating GDL at the base layer were characterized by the data of appearance, contact angle, SEM, EDS, through plane (TP) resistivity, through plane (TP) permeability and assembled single cell polarization curve. The results show that the carbon paper impregnated with PTFE formed the striped hydrophilic area and hydrophobic area. The GDL assembled with alternating hydrophilic and hydrophobic treatment had a voltage of 0.47 V and power density of 948 mW/cm2. In the same case, the GDL assembled with undifferential hydrophobic treatment had 0.44 V and power density of 884 mW/cm2. Compared with the GDL assembled with undifferential hydrophobic treatment, the voltage and power density at 2 A/cm2 increased by 6.82% and 7.24%, respectively.

Key words:gas diffusion layer;carbon paper;hydrophilic/hydrophobic alternation;fuel cell;water management;functional materials