Development of platinum catalyst for lithium oxygen batteries by top-down lithography

Abstract

Lithium–oxygen ($Li–O_2$) batteries are attracting attention around the world as next generation batteries due to their very high energy density. However, there is a challenge that discharge/charge overpotential is large in practical application. In this work, as a cathode, the high monodisperse platinum hole-cylinder nanoparticles (Pt-HCNPs) fabricated by the top-down method dispersed on graphene nanoplatelets (GNP) enhanced the activity in both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), dramatically reducing the overpotential. During the discharge, amorphous $Li_2O_2$ with nanoflake morphology that facilitates formation and decomposition was found. This unique $Li_2O_2$ formation process is suggested as a cause of the reduction mechanism that occurs through the numerous catalytic active sites provided by hole-cylinder morphology and small grain size. These findings suggest a new strategy for the fabrication of catalysts for $Li-O_2$ batteries with high performance through a top-down method called secondary sputtering lithography.