Functionalization of 2D materials for enhancing OER/ORR catalytic activity in Li-oxygen batteries
A Ostadhossein and J Guo and F Simeski and M Ihme, COMMUNICATIONS CHEMISTRY, 2, 95 (2019).
A major barrier toward the practical application of lithium-oxygen batteries is the high overpotential caused by the precipitation of oxygen-reduction products at the cathode, resulting in poor cyclability. By combining first-principle calculations and reactive molecular dynamics simulations, we show that surface functionalization of 2D MXene nanosheets offers a high degree of tunability of the catalytic activity for oxygen-reduction and oxygen-evolution reactions (ORR/OER). We show that the controlled creation of active vacancy sites on the MXene surface enhances ORR in excess of a factor of 60 compared to graphene- based cathode materials. Furthermore, we find that increasing the ratio of fluorine vs. oxygen termination of the functionalized Ti4N3-MXene catalyst reduces the charge overpotential by up to 70% and 80% compared with commercial platinum-on-carbon and graphene catalysts, respectively. These results provide direct guidance toward the rational design of functionalized 2D materials for modulating the catalytic activity for a wide range of electrocatalytic applications.
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