Compared with the reported SiOx@C based anodes, Si-SiOx@C-1.25 reveals superior cycling performance and stability, which are attributed to the twined CNT skeleton structure and the ensuing conductive pathways between SiOx@C and carbon-wrapped silicon (Table ). To further investigate the formation of SEI layer and the properties, in-operando XRD analysis during initial lithiation process was conducted. The cell was assembled in a specially-made split cell with a beryllium window on the top of the electrodes. In operando Raman was also conducted. The cell was assembled in a specially-made split cell with a quartz window on the top of the electrodes with lithium metal as counter electrodes. Fig. and Fig. show the in-operando Raman spectra of Si-SiOx@C-1.25