To verify the chemical valence states of P-Si-SiOx@Cs, XPS analysis was conducted (Fig. ). In Fig. , the N 1s core level spectra of P-Si-SiOx@C, P-Si-SiOx@C-1.25, P-Si-SiOx@C-2.5 and P-Si-SiOx@C-5 exhibit similar peaks from 395 eV to 403 eV, which can be attributed to C=N (400.8 eV) and C-N (398.1) peaks . After carbonization, the detailed morphologies of Si-SiOx@Cs were revealed by SEM. As shown in Fig. , the larger spheres are SiOx@C particles carbonized from the reaction products between GA and APTMS, while the smaller spheres are C-PDA-Si carbonized from PDA-Si. Si-SiOx@C shows a mixture of C-PDA-Si and SiOx@C, while Si-SiOx@C-1.25, Si-SiOx@C-2.5 and Si-SiOx@C-5 exhibit twined-CNTssupported structure, in which the SiOx@C particles depend on CNTs to form with C-PDA-Si filled in. Based on our previous work, the spherical structure of SiOx@C is granted by the crosslinking reaction between GA and APTMS with GA as crosslinkers . To confirm this, the morphology of dried APTMS without adding GA was shown in Fig. , which is flake-like structure rather than spherical structure.