Analysis and review on air-cooled open cathode proton exchange membrane fuel cells: Bibliometric, environmental adaptation and prospect

Air-cooled open cathode proton exchange membrane fuel cells is considered an ideal portable power source due to its lightweight and few auxiliary components. However, the structural characteristics of the cathode side directly exposed to the external environment make its output performance and stability strongly dependent on the surrounding environment. In order to statistically analyze and visualize the research status of air cooled open cathode fuel cells in the past, as well as to study the impact of temperature and humidity environmental factors on the performance, this study first uses bibliometric methods and visualization software VOSviewer and CiteSpace to achieve network analysis of journals, geographical country and institutional collaborations, author collaborations, and keyword terminology co-occurrence. The results show that since 2006, the field has entered a period of active research, with China and the United States possessing global leadership in this field. Furthermore, co-occurrence clustering analysis will be conducted on the main keywords of membrane electrodes, performance, stacks, and control in order to help researchers quickly understand the research frontiers and future development challenges. Finally, the environmental adaptability was analyzed and experimentally studied using an environmental testing platform. The experimental results showed that the performance is not only affected by the operating environment, but also closely related to the storage environment. After a period of storage in high temperature or low humidity environments, the output performance of a single cell/stack significantly decreases, especially in high-temperature storage environments. The higher the temperature of the storage environment in which a single cell is stored, the greater the polarization loss it produces. After the storage test at 75 °C, the polarization loss of a single cell increased to 34.2% of the open circuit voltage under a current density load of 0.8 A/cm2. The performance degradation generated by a single cell/stack during storage will gradually recover after a period of operation and activation, but the time required for stack activation to recover to its optimal state is significantly higher than that of a single cell. The results of this comparative and experimental study not only provide a macro knowledge structure for researchers of air cooled open cathode fuel cell systems, but also emphasize the importance of environmental adaptability, which is an important factor for future research and will directly determine storage and usage performance.