When the added APTMS is dispersed into fine oil droplets under vigorous stirring, the droplets can react with GA molecules to get the precursor of SiOx@C with the outer polymer shell. The simple molecular crosslinking reaction between GA and APTMS insitu produce the polymer spheres based on the CNTs with Si nanoparticles filling in the structure. After freeze-drying and carbonization, the obtained powders exhibit the twined 3D structure seen microscopically. The existence of the polydopamine layer outside silicon nanoparticles has been verified by Raman (Fig. ). The peaks at 1356 and 1585 cm -1 were related to the deformation of catechol . Before carbonization, the chemical structures of P-Si-SiOx@C, P-Si-SiOx@C-1.25, P-Si-SiOx@C-2.5 and P-Si-SiOx@C-5 were characterized by FT-IR (Fig. ). The stretching peaks of -C=Nand C-N in SiOx@C precursors were located at 1640 cm -1 and 1250 cm -1 , respectively, verifying the successful reaction between C=O from GA and -NH2 groups from APTMS and polydopamine after molecular crosslinking reaction. The peaks from 1000 cm -1 to 1200 cm -1 are ascribed to Si-C and Si-O-Si bonds, providing the silicon oxide source after carbonization.