Gold nanocrystals with variable index facets as highly effective cathode catalysts for lithium-oxygen batteries

Cathode catalysts are the key factor in improving the electrochemical performance of lithium–oxygen (Li–O2) batteries via their

promotion of the oxygen reduction and oxygen evolution reactions (ORR and OER). Generally, the catalytic performance of

nanocrystals (NCs) toward ORR and OER depends on both composition and shape. Herein, we report the synthesis of polyhedral

Au NCs enclosed by a variety of index facets: cubic gold (Au) NCs enclosed by {100} facets; truncated octahedral Au NCs

enclosed by {100} and {110} facets; and trisoctahedral (TOH) Au NCs enclosed by 24 high-index {441} facets, as effective

cathode catalysts for Li–O2 batteries. All Au NCs can significantly reduce the charge potential and have high reversible

capacities. In particular, TOH Au NC catalysts demonstrated the lowest charge-discharge overpotential and the highest capacity

of ~ 20 298 mA h g− 1. The correlation between the different Au NC crystal planes and their electrochemical catalytic

performances was revealed: high-index facets exhibit much higher catalytic activity than the low-index planes, as the high-index

planes have a high surface energy because of their large density of atomic steps, ledges and kinks, which can provide a high

density of reactive sites for catalytic reactions.