Lim Ahyoun, Jeong Hui-Yun, Lim Youngjoon, Kim Jin Young, Park Hee Young, Jang Jong Hyun, Sung Yung-Eun, Kim Jong Min, Park Hyun S
Center for Hydrogen, Fuel Cell Research, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea.
School of Chemical and Biological Engineering, Seoul National University, Seoul 08826, Republic of Korea.
Sci Adv. 2021 Mar 24;7(13). doi: 10.1126/sciadv.abf7866. Print 2021 Mar.
Polymer electrolyte membrane unitized regenerative fuel cells (PEM-URFCs) require bifunctional porous transport layers (PTLs) to play contradictory roles in a single unitized system: hydrophobicity for water drainage in the fuel cell (FC) mode and hydrophilicity for water supplement in the electrolysis cell (EC) mode. Here, we report a high-performance amphiphilic Ti PTL suitable for both FC and EC modes, thanks to alternating hydrophobic and hydrophilic channels. To fabricate the amphiphilic PTL, we used a shadow mask patterning process using ultrathin polydimethylsiloxane (PDMS) brush as a hydrophobic surface modifier, which can change the Ti PTL's surface polarity without decreasing its electrical conductivity. Consequently, performance improved by 4.3 times in FC (@ 0.6 V) and 1.9 times in EC (@ 1.8 V) from amphiphilic PTL. To elucidate reason for performance enhancement, discrete gas emission through the hydrophobic channels in amphiphilic PTL was verified under scanning electrochemical microscopy.
聚合物电解质膜单电池再生燃料电池（PEM - URFCs）需要双功能多孔传输层（PTLs）在单个单电池系统中发挥相互矛盾的作用：在燃料电池（FC）模式下具有疏水性以排水，在电解池（EC）模式下具有亲水性以补水。在此，我们报道了一种适用于FC和EC模式的高性能两亲性Ti PTL，这得益于交替排列的疏水和亲水通道。为了制备两亲性PTL，我们使用了一种荫罩图案化工艺，该工艺使用超薄聚二甲基硅氧烷（PDMS）刷作为疏水表面改性剂，它可以改变Ti PTL的表面极性而不降低其电导率。因此，两亲性PTL使FC（@ 0.6 V）性能提高了4.3倍，EC（@ 1.8 V）性能提高了1.9倍。为了阐明性能增强的原因，在扫描电化学显微镜下验证了通过两亲性PTL中疏水通道的离散气体排放。
