Hierarchical shuttle-like Li2FeSiO4 as a highly efficient cathode material for lithium-ion batteries

Abstract

We successfully synthesized the novel hierarchical shuttle-like Li2FeSiO4 using one step hydrothermal method with ethylene glycol assisted. The growth mechanism of the shuttle-like Li2FeSiO4 constructed of nanosingle crystals was discussed and its electrochemical performance as a cathode material for lithium ion battery was investigated. Astonishingly, the 1st discharge specific capacity of the new material without carbon coating was 180.6 mA h g−1 at 0.1 C with a remarkably high Coulombic efficiency of 97.5%, and an improved high-rate capability (71.0 mA h g−1 at 2 C) was offered which is comparable to the commonly carbon-coated Li2FeSiO4. Moreover, it exhibited a very stable discharge specific capacity at current densities from 0.1 to 2 C. Its excellent electrochemical performance can be ascribed to the significantly improved diffusion coefficient of lithium ions (5.6421 * 10−11 cm2 s−1), which was greatly larger than the reported carbon-coated Li2FeSiO4 nanocomposites and diatomic metallic ions (Ni2+, Cu2+, Zn2+) doped Li2FeSiO4. These indicate the shuttle-like Li2FeSiO4 is a very promising cathode material for lithium-ion batteries.