## 1 Introduction  
The increasing global demand for energy and urgent environmental concerns have driven the development of innovative technologies aimed at reducing dependence on fossil fuels [1]. While renewable energy sources such as wind, solar, and hydro hold great promise, their intermittent nature presents a challenge that requires effective solutions for energy storage [2]. In this context, green hydrogen derived from renewable sources has emerged as a high-energy-density vector for energy storage and transportation [3]. As a result, fuel cells are gaining prominence as clean and efficient alternatives to conventional combustion engines, particularly in transportation applications [4]. Fuel cells exhibit high efficiency by converting a significant portion, up to 63%, of the chemical energy contained in the fuel into electricity [5], surpassing the typical efficiency levels achieved with internal combustion engines [6]. Furthermore, an additional advantage of fuel cells is that they solely generate water as a by-product, resulting in a significant reduction in environmental impact compared with engines that release harmful pollutants [7]. In contrast to batteries, fuel cells offer a higher energy density, enabling the storage of larger amounts of energy in a smaller volume [8] and facilitate faster refueling times [9]. Among the different types of fuel cells available, the proton-exchange membrane fuel cell (PEMFC) is the most commonly used variant [10], especially in the transportation sector. Polarization curves are vital in fuel cell performance analysis, highlighting the voltage-current density relationship and energy efficiency [11]. Particularly in PEMFC studies, these curves have allowed the assessment of the activation, ohmic, and concentration losses, each varying with cell design and operation [12; 13]. Activation losses arise from slow electrochemical reactions at fuel cell electrodes, influenced by electrode materials, catalyst properties, operation temperature, and gas properties [14]. Such losses are characterized by a sudden voltage drop under low current density conditions, reaching values between 0.9 and 0.7 V in this region. Conversely, ohmic losses stem from the electrical resistance encountered by the protons in the electrolyte membrane and by the electrons in the current collectors [15]. This linear trend appears from the end of the activation losses area to a value around 0.6-0.4 V. Lastly, concentration (or transport) losses, occurring from 0.6 to 0.4 V, are identified a sudden voltage decrease in a narrow range of current density. Concentration losses arise due to the depletion of reactants, particularly O2 at the cathode [16], becoming prominent when mass transfer limitations occur [17]. The O2 concentration plays a vital role in determining the extent of activation [18] and concentration losses [19]. Activation losses are aggravated by the hindrance of electrochemical reactions caused by the low partial pressure of O2 during low-current conditions [20]. A substantial reduction in activation losses, reaching 92%, was reported following an increase in O2 concentration from 24% to 100%. This improvement translates to enhanced efficiency across the entire range of current densities [21]. Moreover, a decrease in O2 concentration intensifies concentration losses by impeding reactant supply to the electrodes, resulting from mass transfer limitations between the gas channel and the catalytic layer of the cathode [22]. In certain fuel cell applications, particularly in the marine sector, specialized systems are employed to enhance the concentration of O2 in the cathode feed stream [23]. The O2 enrichment in the cathode feed stream has undergone extensive investigation for its potential to enhance performance and efficiency in PEMFCs [24]. [PERSON] et al. [25] demonstrated that O2 enrichment offers a notable advantage in increasing the power output of fuel cells at the working current density.