Mesoporous Li2FeSiO4/C nanocomposites with enhanced performance synthesized from fumed nano silica

Mesoporous Li 2 FeSiO 4 /C nanocomposites (LFS-FNS and LFS-NS) were prepared from fumed nano silica (FNS) and nano silica (NS) through facile solid-state reactions, respectively. XRD analysis indicates that the crystalline structures of LFS-FNS and LFS-NS are indexed to monoclinic Li 2 FeSiO 4 of P2 1 . SEM results prove that the particle size of LFS-FNS and FNS (25~40 nm) is smaller than that of LFS-NS and NS, revealing the particle size of Li 2 FeSiO 4 /C nanocomposites can be tuned by choosing different silica. TEM further indicates Li 2 FeSiO 4 nanoparticles are uniformly dispersed in the amorphous carbon networking of LFS-FNS. Pore structure analysis indicates the external surface areas of LFS-FNS as well as LFS-NS are 51.4 and 36.1 m 2  g −1 , indicating the pore properties of mesoporous Li 2 FeSiO 4 /C nanocomposites can be controlled by using different silica as silicon resource. The reduced particle size and high external surface area shorten the lithium-ion diffusion path and make LFS-FNS possess better electrochemical performance over LFS-NS. The discharge capacity of LFS-FNS is as high as 172 mA h g −1 at 0.1 C.