Negatively-Doped Conducting Polymers for Oxygen Reduction Reaction

The oxygen reduction reaction (ORR) limits the efficiency of oxygen-associated energy conversion in fuel cells and air-metal batteries. Today, expensive noble metal catalysts are often utilized to enhance the ORR and the resulting conversion efficiency in those devices. Hence, there is an intensive research to find efficient electrodes, exhibiting a favorable electronic structure, for ORR based on abundant materials that can be manufactured using low cost processes. In that context, metal-free carbon-based nanostructures and conducting polymers have been actively investigated. The negatively doped poly(benzimidazobenzophenanthroline) (BBL) as an efficient and stable oxygen cathode material is reported here. Compared to the benchmark p-doped conducting polymer poly(3,4-ethylendioxythiophene) (PEDOT), the BBL provides electrocatalysis that fully reduces dioxygen into water, via a (2 + 2)-electron transfer pathway with hydrogen peroxide (H2O2) as an intermediate; while PEDOT limits the ORR to H2O2. It is demonstrated that n-doped BBL is a promising air electrode material for low-cost and ecofriendly model fuel cells, without the need of any co-catalysts, and its performance is found to be superior to p-doped PEDOT air electrodes.

Automated summary

The oxygen reduction reaction (ORR) is a bottleneck for energy conversion efficiency in fuel cells and air-metal batteries, and there is a growing interest in finding efficient electrodes based on abundant materials. This study introduces a negatively doped poly(benzimidazobenzophenanthroline) (BBL) as a promising air electrode material, surpassing p-doped PEDOT in performance for low-cost and ecofriendly model fuel cells.