The CCMswere annealed by hot-pressing at 140  C and 2.8MPa for 3min, and then theywere assembled with two gas diffusion layers (GDLs, 25BCH, SGL Carbon Group Co., Ltd.) and a single serpentine pattern cell (Japan Auto- mobile Research Institute (JARI) standard cell) with an active geo- metric area of 29.2 cm2.