Constructing inverse opal antimony@carbon frameworks with multi-level porosity towards high performance sodium storage

Metal antimony (Sb) has excellent electrical conductivity and high theoretical capacity of sodium storage based on alloy reaction mechanism and possesses great application potential in sodium ion batteries (SIBs). However, serious material fracture and volume expansion during the alloy reaction greatly hinder its commercialization process. To overcome these issues, herein a construction method combining ordered silica template, viscous sol casting and high temperature gel reduction is proposed for fabricating ordered 3D antimony/carbon inverse opal framework (3D Sb/C). With the confining effect of the templates, active antimony nanoparticles are highly dispersed. After the etching process, macroporous inverse opal framework can be constructed. The following repeated oxidation and reduction process on active antimony modifies the surrounding microscopic environment, further forming a huge number of mesopores, and finally resulting in the formation of multi-level porous structure. The acquirement of the 3D Sb/C inverse opals realizes the multiple engineering modulations for SIB application, which is conducive to the exposure of active sites, the buffer of volume expansion, and the path of rapid ion diffusion/electron transfer. Benefiting from these structure advantages, the 3D Sb/C 250 inverse opals exhibit excellent sodium storage capacity (550.4 mAh g −1 at 0.1 A g −1 ) and cyclic stability (257.9 mAh g −1 after 200 cycles at 1 A g −1 ). • 3D antimony@carbon inverse opal framework (3D Sb/C) was constructed as SIB anode. • Silica template, sol casting and gel reduction are combined for 3D Sb/C construction. • Active antimony nanoparticles are highly dispersed in carbon inverse opal framework. • The repeated oxidation and reduction process results in multi-level porous structure. • 3D Sb/C with the novel porous structure exhibits excellent Na storage performances.