High-temperature polymer electrolyte membranes: Proton conductivity and performance of polybenzimidazole/Ti0.9Mn0.1P2O7

Polymer electrolyte membranes have proven to be highly successful in creating efficient, emission-free fuel cells, but their low-temperature limitation restricts full potential utilization. To address this issue, in the present work, polybenzimidazole (PBI)/Ti 0.9 Mn 0.1 P 2 O 7 (TMP) inorganic-organic composite membranes were fabricated, and their morphological and structural characterizations were performed. Before testing, all membranes were loaded with phosphoric acid . The resulting PBI/TMP composite membrane has a higher proton conductivity of 212.3 mS cm −1 and activation energy ⁓ 5.49 kJ mol −1 as compared to the pristine PBI membrane with protonic conductivity 102.7 mS cm −1 and activation energy ⁓ 1.24 kJ mol −1 . The PBI/TMP membrane can function effectively up to 180 °C, achieving a maximum peak power density of 376 mW cm −2 at the current density of 1120 mA cm −2 with the open circuit potential ⁓0.940 V. The inclusion of TMP significantly enhances overall cell performance compared to pristine PBI, where the peak power density of 364 mW cm −2 and current density of 958 mA cm −2 at 180 °C were obtained with an open circuit potential of 0.819 V. This study revealed successfully the potential of PBI/TMP composite membranes for their application in high-temperature proton exchange membrane fuel cells. • PBI/Ti 0.9 Mn 0.1 P 2 O 7 composite membrane were synthesized and studied. • Composite membrane exhibits good thermal stability and mechanical strength. • PBI/TMP composite membrane shows max. Conductivity 212.3 mS cm −1 at 180 °C. • FC with PBI/TMP shows OCV = 0.940 V and power density = 376 mWcm −2 at 1120 mA/cm −2 . • TMP improves the performance of PBI membranes at elevated temperatures.