Three Dimensionally Ordered Mesoporous Carbon as a Stable, High-Performance Li-O2 Battery Cathode

Enabled by the reversible conversion between Li2O2 and O2, Li–O2 batteries promise theoretical gravimetric capacities significantly greater than Li‐ion batteries. The poor cycling performance, however, has greatly hindered the development of this technology. At the heart of the problem is the reactivity exhibited by the carbon cathode support under cell operation conditions. One strategy is to conceal the carbon surface from reactive intermediates. Herein, we show that long cyclability can be achieved on three dimensionally ordered mesoporous (3DOm) carbon by growing a thin layer of FeOx using atomic layer deposition (ALD). 3DOm carbon distinguishes itself from other carbon materials with well‐defined pore structures, providing a unique material to gain insight into processes key to the operations of Li–O2 batteries. When decorated with Pd nanoparticle catalysts, the new cathode exhibits a capacity greater than 6000 mAh gcarbon−1 and cyclability of more than 68 cycles. Concealed: To address the issue of carbon‐support instability in Li–O2 batteries, a layer of FeOx grown on the carbon surface by atomic layer deposition (ALD) is used to physically separate a three dimensionally ordered mesoporous carbon support from the electrolyte. When the FeOx surface is decorated with ALD‐grown Pd nanoparticles, the cyclability of the cathode is significantly enhanced.