Electrochemical and X-ray absorption spectroscopy studies of anode materials for rechargeable batteries

Industrial upgrading in electric vehicles and portable electronic devices poses a great challenge to develop better rechargeable batteries. Establishing the structure-function relationship is significant for promoting the development of rechargeable batteries. Advanced materials design that tailors nanostructures and physicochemical properties can improve battery performance, whilst synchrotron X-ray absorption spectroscopy (XAS) can facilitate this by probing the electronic and local atomic structure of specific redox centers of the electrodes. This doctoral work investigates the engineering of the nanostructures/constituents of the anode materials and unraveling the electrochemical mechanisms of anode materials with an emphasis on XAS studies so as to break through the performance bottleneck of rechargeable batteries First, nanostructured Sb embedded in N-doped carbon matrices were prepared by a facile one-step and solvent-free pyrolysis method. By adjusting the experimental conditions, different hybrid architectures can be obtained, including hollow Sb embedded in holeless carbon matrices (Sb@G0.25N0.5-950) and Sb nanoplates embedded in holey carbon matrices (Sb@G0.25N0.25-950). It suggests that the formation of diverse nanostructures is closely related to the sublimation and evaporation of Sb, and the structural remolding of liquid Sb by surface tension. Benefitting from these unique structural features, these optimized electrodes show highly reversible sodium storage with high specific capacities and good cycling stability.