Large-scale facile synthesis of Fe-doped SnO2 porous hierarchical nanostructures and their enhanced lithium storage properties

Abstract

Metal oxide porous hierarchical structures are of great significance because of their unique structure-dependent physico-chemical properties and wide applications. Herein, a flower-like Fe-doped SnO₂ (Sn_1−xFe_xO₂) porous hierarchical architecture was successfully fabricated via a facile coordination polymer (CP) precursor approach. The precursor Sn_m[Fe(CN)₆]_n with a flower-like hierarchical structure composed of interconnected nanoplates was obtained by the reaction between Sn²⁺ and [Fe(CN)₆]³⁻ in aqueous solution at ambient temperature without using any surfactant or template. The calcination of the precursor produces a Sn_1−xFe_xO₂ hierarchical architecture without any obvious morphological deformation but with numerous mesopores in the nanoplates. The Brunauer–Emmett–Teller N₂ adsorption–desorption analysis showed that the sample of Sn_0.72Fe_0.28O₂ obtained under 350 °C calcination had a specific surface area as high as 108.57 m² g⁻¹ with a pore size of ca. 4 nm. When evaluated as negative electrode materials for lithium-ion batteries, the sample showed a high initial specific capacity of 1281.3 mA h g⁻¹ at a current density of 200 mA g⁻¹, and retained a specific capacity of 600.5 mA h g⁻¹ at the 100th cycle. The significantly enhanced performance towards lithium storage could be attributed to the cooperation of the highly stable hierarchical architecture, porous nanoplate building blocks, and Fe-doping in the SnO₂-based materials. It is believed that this facile CP precursor route can be extended to fabricate other doped metal oxide porous hierarchical structures with various functions.