Nanoporous tree-like SiO2 films fabricated by sol–gel assisted electrostatic spray deposition

A novel nanoporous tree-like SiO2 film was synthesized by a sol–gel assisted electrostatic spray deposition (SG-ESD) approach. The sol–gel process employed was better to create SiO2 with linear cross-link chains for the electrostatic spray deposition. From electron microscopic study, it was found that the as-deposited SiO2 films possess nanoporous tree-like morphology in macroscale; and monodispersed hollow nanoporous spherical structure in microscale. The formation of the nanoporous “tree” structure is related to the preferential landing of droplets on the substrate and the electrostatic repulsion force among landing droplets during the ESD process. The catalytic effect of hydrochloric acid in the sol–gel system contributes to the formation of the hollow and porous structured SiO2 spheres. The charge-discharge characteristics of the porous SiO2 as an anode for Li-ion batteries were briefly evaluated and good long-term cycle performance was reached.

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► Nanostructured SiO2 was synthesized.
► The structure possesses porous and nano-tree-like morphology in macroscale.
► The structure possesses monodispersed nanoporous spherical structure in microscale.
► Obtained SiO2 shows good cycle performance as anode for lithium ion batteries application.