Systematic study on the discharge product of Pt-based lithium oxygen batteries

Lithium oxygen batteries have attracted much attention due to the high theoretical energy density. However, they suffer a large overpotential during oxygen evolution process and thus catalysts play a vital role in the reaction. Here, we systematically explored the influence of Pt-based nanoparticle catalysts on the discharge product Li₂O₂. Because of the superior electrical conductivity and the strong binding with oxygen, Pt-based nanoparticles serve as active sites which are favorable for the growth of toroidal Li₂O₂. We also found that the content and composition of Pt-based nanoparticle catalysts exert a significant influence on the electrochemical performance of lithium oxygen batteries. The discharge products are composed of crystalline Li₂O₂ and oxygen-rich LiO₂ characterized by high-energy X-ray diffraction and Raman. Atomic force microscopy further provides detailed information of the particle size and surface roughness. The loading of Pt catalysts determines the phase and size of Li₂O₂ on the discharged electrode surface. This study will be beneficial for the optimization of Pt-based catalysts used in non-aqueous lithium oxygen batteries.