Exploring the engineered electroplating process for coating of gold on the inner structure of porous transport layer (PTL): Performance evaluation of coating in simulated PEM electrolyzer
Aditya Singh, Biswajit Samir De, Sukhvant Singh, Sai Praneeth Thota, Mohmmad Khalid, Samaneh Shahgaldi
Abstract
During prolonged operation of PEM water electrolyzer (PEMWE) in an acidic environment, the formation of TiO 2 on the surface of the Ti-PTL causes passivation, resulting in an increase in the cell voltage. Herein, the Ti-PTL treatment involved three steps: electrochemical etching to remove surface oxides, electrostriking to form an Au underlayer and electroplating to apply a protective top layer of Au. The Au was uniformly distributed on the top of the surface and inner structure of Ti-PTL under the optimized rotation speed of 50 rpm, denoted by Au/Ti felt [R = 50]. The Ti-PTL treatment under optimized rotation presented a more effective anticorrosive coating in simulated conditions of a PEMWE compared to treatments without rotation and those with high rotation of 200 rpm. In PEMWE cell, the Au/Ti felt [R = 50] PTL demonstrated a voltage reduction of 124 mV compared to Au/Ti felt [R = 0] at 2.0 A/cm 2 . The corrosion study and durability measurements were conducted using a homemade simulated flow corrosion cell. 3D printing was employed to fabricate non-metallic bipolar plates (BPs) that included a simulated flow field structure at the PTL/BP interface. This approach paves the way to independently observe the impact on cell voltage caused by the degradation of the PTL. • Development of engineered electroplating method to coat inner structure of the PTL. • Optimized rotation of substrate during electroplating offered uniform gold coating. • 3D printed non-metallic BPs were assembled to create simulated BPs/PTL interface. • Conducted the comprehensive ex-situ and in-situ characterizations. • Optimized rotating Au coated PTL offered PEMWE performance of 1.742 V at 2.0 A/cm 2 .