Fluorinated strategy of node structure of Zr-based MOF for construction of high-performance composite polymer electrolyte membranes

Carbonized Polymer Dots Assemble in Proton-Conducting Channels to Enhance the Conductivity and Selectivity Simultaneously for High-Performance Fuel Cells

Fabricating polymer electrolyte membranes (PEMs) simultaneously with high ion conductivity and selectivity has always been an ultimate goal in many membrane-integrated systems for energy conversion and storage. Constructing broader ion-conducting channels usually enables high-efficient ion conductivity while often bringing increased crossover of other ions or molecules simultaneously, resulting in decreased selectivity. Here, the ultra-small carbon dots (CDs) with the selective barriers are self-assembled within proton-conducting channels of PEMs through electrostatic interaction to enhance the proton conductivity and selectivity simultaneously. The functional CDs regulate the nanophase separation of PEMs and optimize the hydration proton network enabling higher-efficient proton transport. Meanwhile, the CDs within proton-conducting channels prevent fuel from permeating selectively due to their repelling and spatial hindrance against fuel molecules, resulting in highly enhanced selectivity. Benefiting from the improved conductivity and selectivity, the open-circuit voltage and maximum power density of the direct methanol fuel cell (DMFC) equipped with the hybrid membranes raised by 23% and 93%, respectively. This work brings new insight to optimize polymer membranes for efficient and selective transport of ions or small molecules, solving the trade-off of conductivity and selectivity.

Research on Energy and Economics of Self-Made Catalyst-Coated Membrane for Fuel Cell under Different Oxidants

In the context of global warming, clean energy represented by fuel cells has ushered in a window period of rapid development; however, most research mainly focuses on the improvement of catalysts and performance, and there is very little research on the performance differences and energy consumption between different oxidants. In this paper, the performance differences of fuel cells with different oxidants (air and oxygen) are studied using a self-made CCM, and the economic aspect is calculated from the perspective of power improvement and energy consumption. Firstly, the CCM and GDL are prepared, and the hydrophilicity and hydrophobicity of GDL are realized by the addition of PTFE and SiO₂, respectively. Secondly, through the experiment, it is found that the fuel cell can achieve the best comprehensive performance at 60 °C, and the use of oxygen can achieve the highest power increase, 117.1%, compared with air. Finally, from the perspective of economics, after excluding the power consumed for preparing oxygen, the use of oxygen as an oxidant still achieved a net power increase of 29.512%. The research in this paper clearly shows that using oxygen instead of air can greatly improve performance and is good economically, which makes it a useful exploration for the research of fuel cells.