A universal surface enhanced Raman spectroscopy (SERS)-active graphene cathode for lithium-air batteries

Nonaqueous lithium-air (Li-O-2) batteries, with their high theoretical energy densities far exceeding those of conventional Li-ion batteries, have attracted significant research interest over the past decade. However, the practical realization of Li-O-2 batteries is still confronted with the challenge of electrode side reactions that lead to severe solvent/electrode degradation upon cycling. To understand the reaction process on the electrode, it is necessary to obtain detailed information about the chemicals formed on the Li-O-2 battery electrode. Herein, a universal method to fabricate large-area regularly patterned gold nano-dots using an anodic aluminum oxide (AAO) mask was developed. The gold nano-dots were patterned on to conductive substrates such as Au film and graphene, and then the films were used as SERS (Surface Enhanced Raman Spectroscopy)-active cathodes in Li-O-2 batteries. The discharge products on the different electrodes (graphene and gold) were analyzed and the results indicated that the SERS electrode will be a useful tool for studying the reaction process on lithium-air cathodes.