One major challenge associated with proton exchange membrane fuel cells is to preserve higher proton conductivity under low-humidity atmosphere. Elevation of water uptake in the perfluorinated polymeric membrane is crucial for the facilitated transportation of proton, which dominates the fuel cell performance. Development of an intrinsic mechanism that controls water balance through the membrane electrode assembly (MEA), eliminates the need for external water management system and thus makes the system suitable for portable applications, where size is an important criterion to be considered. Herein, we report a nano-sized dense-structure (NSDS) layer coated onto the conventional catalyst layer, forming a dual-layered electrode architecture that is favorable in promoting the self-humidification process. This self-humidifying layer is fabricated by the electrostatic spray deposition with sufficiently low deposition rate, which allows for a creation of more uniformly distributed porous structure with diameters smaller than 80 nm, enabling recirculation of the water generated for proper humidification. When experimentally investigated, the MEA employing the dual-layered electrode reveals a 3.15 times elevated current density at 0.6 V than conventional MEA under 0% relative humidity. Mechanism for the water retention in the proposed electrode is further evaluated by X-ray computed tomography, which reveals dramatically increased tortuosity of 4.43 for the NSDS layer in comparison to 1.9 for the conventional catalyst layer.

与质子交换膜燃料电池相关的一个主要挑战是在低湿度气氛下保持较高的质子传导性。全氟聚合物膜中水吸收的增加对于促进质子的运输至关重要，质子占主导地位的是燃料电池的性能。开发通过膜电极组件（MEA）控制水平衡的内在机制，消除了对外部水管理系统的需求，因此使该系统适合于便携式应用，在便携式应用中，尺寸是要考虑的重要标准。在本文中，我们报道了涂覆在常规催化剂层上的纳米级致密结构（NSDS）层，形成了有利于促进自加湿过程的双层电极体系结构。该自增湿层通过具有足够低的沉积速率的静电喷涂沉积来制造，这允许产生直径小于80nm的更均匀分布的多孔结构，从而能够使产生的水再循环以进行适当的增湿。当进行实验研究时，在0 V相对湿度下，采用双层电极的MEA在0.6 V电压下的电流密度是常规MEA的3.15倍，是传统MEA的3.15倍。通过X射线计算机断层扫描进一步评估了拟议电极中保水的机理，与常规催化剂层的1.9相比，NSDS层的弯曲度显着提高了4.43。这样可以产生直径小于80 nm的更均匀分布的多孔结构，从而使产生的水再循环以进行适当的加湿。当进行实验研究时，在0 V相对湿度下，采用双层电极的MEA在0.6 V电压下的电流密度是常规MEA的3.15倍，是传统MEA的3.15倍。通过X射线计算机断层扫描进一步评估了拟议电极中保水的机理，与常规催化剂层的1.9相比，NSDS层的弯曲度显着提高了4.43。这样可以产生直径小于80 nm的更均匀分布的多孔结构，从而使产生的水再循环以进行适当的加湿。当进行实验研究时，在0 V相对湿度下，采用双层电极的MEA在0.6 V电压下的电流密度是常规MEA的3.15倍，是传统MEA的3.15倍。通过X射线计算机断层扫描进一步评估了拟议电极中保水的机理，与常规催化剂层的1.9相比，NSDS层的弯曲度显着提高了4.43。在0％相对湿度下，0.6 V时的电流密度是传统MEA的15倍。通过X射线计算机断层扫描进一步评估了拟议电极中保水的机理，与常规催化剂层的1.9相比，NSDS层的弯曲度显着提高了4.43。在0％相对湿度下，0.6 V时的电流密度是传统MEA的15倍。通过X射线计算机断层扫描进一步评估了拟议电极中保水的机理，与常规催化剂层的1.9相比，NSDS层的弯曲度显着提高了4.43。