Hierarchical mesoporous Li2FeSiO4/C sheaf-rods as a high-performance lithium-ion battery cathode

Hierarchical mesoporous Li 2 FeSiO 4 /C sheaf-rods (HMLFS-SRs) were fabricated using a hard template method with SBA-15 as a silicon source. For comparision, Li 2 FeSiO 4 /C nanocomposites (LFS) were prepared using nano-SiO 2 under the same conditions. XRD results prove that both the HMLFS-SRs and LFS contain crystalline Li 2 FeSiO 4 and trace amounts of Fe 3 O 4 impurities. The SEM and TEM images indicate that the HMLFS-SRs are hierarchical sheaf rods composed of nanoparticles . EDS data prove that elemental Fe, Si, O and C are uniformly distributed throughout the whole Li 2 FeSiO 4 /C sheaf rod. Nitrogen adsorption/desorption analyses further indicate that the HMLFS-SRs are typical mesoporous materials with an external surface area of 47 m 2  g −1 , which is higher than that of the LFS (31 m 2  g −1 ). These unique structures enable the HMLFS-SRs to exhibit much better electrochemical performance than the LFS. The HMLFS-SRs deliver a high discharge capacity of 206.6 mAh g −1 at 0.1 C. In addition, the HMLFS-SRs also have good cycling performance, satisfactory rate performance, a low charge transfer resistance and a large lithium-ion diffusion coefficient .