Vitamin E assisted polymer electrolyte fuel cells

Abstract

Due to breathing O₂ from the air, vertebrates can suffer from diseases originating from oxidative stress. These, however, can be relieved by various antioxidants. Similarly, proton exchange membrane fuel cells (PEMFCs) suffer from the major problem of limited lifetimes, caused by chemical attacks by reactive oxygen species (ROS). Inspired by vertebrates, we herein show that the incorporation of a natural antioxidant, α-tocopherol (α-TOH), the most abundant component of vitamin E, which acts as a free radical scavenger, enables a maintenance of performance for PEMFCs which is impossible to achieve for fuel cells in the absence of α-TOH. It is notable that oxidized α-TOH can in turn be reduced by permeated H₂ during fuel cell operation, resulting in its regeneration. Such reversibility leads to a chemical circulation system, which not only ensures the effective recycling of α-TOH, but also permits efficient protection of proton exchange membranes (PEMs) and thus allows their long-term operation.