Critical importance of current collector property to the performance of flexible electrochemical power sources

Abstract

Flexible electrochemical power sources are attracting increasing attentions for their unique advantages like flexibility, shape diversity, light weight and excellent mechanical properties. In this research, we discover that the current collector can dramatically affect the performance of flexible electrochemical power sources with large size. For flexible air-breathing proton exchange membrane fuel cell (PEMFC), the performance could have more than 8 times increase by only adjusting the directions of current collectors. The different performances of different current collection types are mainly attributed to the diverse lengths of the electron transfer pathways. In addition, the conductivity of current collector can dramatically affect the capability of flexible PEMFCs with large-size. The flexible PEMFCs with thicker carbon nanotube membrane as current collector (low electric resistance) show higher ability. A mathematic model is successfully built in this work to further understand the performance. Moreover, the model and simulation are also applicable to other flexible power sources, such as flexible Li-ion battery and supercapacitor.