An ultrathin substrate-free gas diffusion layer for proton exchange membrane fuel cell

The gas diffusion layer (GDL) is a key component responsible for mass transfer in the proton exchange membrane fuel cell (PEMFC); however, the conventional commercial GDLs exist with series of disadvantages of the long mass transfer routine, high cost of the substrate layer, and complex preparation processes. To address these problems, we develop a novel substrate-free gas diffusion layer (sfGDL) composed of the whisker carbon nanotubes and Ketjen blacks as a crack-free micrometer network structure. Such a unique sfGDL exhibits a competitively high power density of 1.37 W cm-2 at 100 % relative humidity and 3.77 A cm-2 current density at 0.2 V. Besides, compared with the conventional GDLs, the thickness of sfGDL in this work is significantly reduced by 40 %, indicating great potential for practical applications. This work paves a new way to boost the high performance of PEMFCs.