N-doped pierced graphene microparticles as a highly active electrocatalyst for Li-air batteries
In this work we report a novel scalable strategy to prepare a lithium-air battery electrode from 3D N-doped pierced graphene microparticles (N-PGM) with highly active performance. This approach has combined the merits of spray drying technology and the hard template method. The pierced structured graphene microparticles were characterized physically and electrochemically. An x-ray photoelectron spectrometer and Raman spectra have revealed that the novel structure possesses a higher N-doping level than conventional graphene without the pierced structure. A much higher BET surface area was also achieved for the N-PGM than the conventional N-doped graphene microparticles (N-GM). Cyclic voltammetry indicated that the lithium-air battery with the N-PGM electrode has a better utilization for the graphene mass and a higher void volume for Li2O2 formation than that of the N-GM electrode. N-PGM also exhibits improved decomposition kinetics for Li oxide species yielded in the cathodic reaction. Charge and discharge measurements showed that the N-PGM lithium-air battery achieved an improved specific capacity and an enhanced cycle performance than when an N-GM electrode is used.