Evaluation and optimization of microfluidic fuel cell with filter paper separator

Membraneless microfluidic fuel cells hold significant promise for wearable and implantable devices due to their potential for miniaturization and clean energy production. However, their output performance is constrained by mass transfer limitations and the difficulty of reactants binding to active sites, issues caused by carbon dioxide generated from oxidation in acidic conditions. To address these, a novel flow through anode microfluidic fuel cell structure with a filter paper separator is proposed to restrict carbon dioxide diffusion to the cathode while enhancing ion transfer. A two-phase numerical model is developed to investigate the internal gas-liquid separation mechanisms, with deviation and fitting analyses conducted using prior experimental data to validate the models. Additionally, the design is further optimized by incorporating a bubble-trap layer to mitigate carbon dioxide accumulation in the anode and flow channel. This re-optimized structure achieves a 41.07% reduction in the average carbon dioxide volume fraction in the anode, while increasing the maximum power density and current density to 23.97 mW cm-2 and 140.36 mA cm-2, respectively. These optimized designs and multi-evaluations, conducted through the numerical model, provide a theoretical foundation for improved two-phase flow management and reduced adverse effects of carbon dioxide. [Display omitted] •The availability of filter paper for separating CO2 gas is studied.•A bubble-trap layer is introduced for filter paper separator.•The dual-separation structure is studied.•The mass transfer in various gas-liquid separation structures are compared.