NaCl Pinning Induced Ultrafine Sn Nanoparticles Anchored on Three-Dimensional Porous Carbon for Na Storage

Engineering of the composite composed of ultrafine Sn nanocrystallites uniformly dispersed on three-dimensional porous carbon (3DC) remains a challenge. In this work, ultrafine SnO2 nanoparticles coated with TPB were prepared by a solvothermal method first. During this process, the generated TPB formed a thick coating layer outside the SnO2 nanoparticles, which can limit the growth and inhibit the agglomeration of SnO2 nanoparticles. Then the SnO2@TPB was dispersed on the surface of the NaCl cubic crystal template uniformly coated by C6H5O7 (NH4)(3) by freeze-drying. Finally, TPB and C6H5O7(NH4)(3) were carbonized synchronously and became a solid and intact carbon community with abundant pores under the template effect of NaCl, and the SnO2 nanoparticles were reduced to monodisperse ultrafine Sn nanoparticles uniformly and firmly anchored on porous 3D carbon (Sn@C@3DC) under the combined action of the nanospatial confined effect and pinning effect of the NaCl template. Benefiting from monodisperse ultrafine Sn nanoparticles to alleviate their huge volume expansion, the ultrathin 3D carbon network to promote the diffusion of electrons and ions provides a space to cushion the expansion of Sn nanoparticles. The firm connection between ultrafine Sn and 3DC can heighten the structural stability of Sn@C@3DC. Therefore, the Sn@C@3DC composite as an SIB anode material exhibited prominent electrochemical performance, notably the rate performance and extremely long-cycling stability even at 10 A g(-1).