We developed a new separator with a multi-hole structure (MHS) in the rib region for opencathode polymer electrolyte membrane fuel cell (OC-PEMFC) stack to improve performance. The electrochemical current-voltage performance results clearly demonstrate that the performance of the OC-PEMFC stack using the MHS design was higher than that using the conventional parallel design at high current regions (i.e., over 7 A). The current increased by 11.24% at 12 V (i.e., 0.6 V/cell). The effects of supplying additional oxygen and removing generated water were identified as factors improving the performance. The individual cell voltages demonstrate that the initial value of standard deviation for the OC-PEMFC stack using MHS was somewhat high, but it exhibited better uniformity at higher current regions. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.