Ambient lithium–air battery enabled by a versatile oxygen electrode based on boron carbide supported ruthenium

Abstract

Li-air batteries (LABs) operated in ambient air containing moisture and CO2 highly desire the oxygen electrodes to have capability of Li2CO3 and LiOH decomposition and electrochemical stability. Here we report the application of a stable non-carbon based oxygen electrode based on boron carbide supported ruthenium (Ru/B4C) for ambient LABs. LABs using Ru/B4C deliver a discharge capacity of 2689 mA h g−1 and voltage plateaus of 2.7 V and 3.8 V for discharge and charge process, respectively at 0.1 mA cm−2, which are comparable to those for Ru/B4C-based Li–O2 battery (2796 mA h g−1, 2.8 V and 3.7 V, respectively). Under limited capacity of 300 mA h g−1, LAB exhibits 45 stable cycles, close to the 50 cycles for its Li–O2 battery counterpart. The typical product for the first discharge for LAB is the mixture of Li2CO3 and Li2O2 with relative content ratio of 62:38, which cannot be detected after the first charge. The non-carbon based Ru/B4C oxygen electrode provides a promising approach for the stable operation of LABs in ambient air.