Hydrothermal synthesis and electrochemical performance of nanoparticle Li2FeSiO4/C cathode materials for lithium ion batteries

Li2FeSiO4 nanoparticles are successfully synthesized via hydrothermal approach, with the hydrothermal process monitored in detail. Structural characterizations by XRD, FTIR, SEM and HRTEM measurements reveal that the Li2FeSiO4 nanoparticles have a high crystalline degree and monodisperse nanoparticle shape with a size around of 50–200 nm. To further improve the electronic conductivity, the Li2FeSiO4 nanoparticles are coated by a carbon layer using in suit polymerization of dopamine. Moreover, the effect of carbon content for electrochemical performance of Li2FeSiO4/C is systemically investigated, and as a result, the composite with a ratio of Li2FeSiO4 and dopamine of 3:1 demonstrate the best electrochemical performance with a discharge specific capacity of 148 mA h g−1 at a rate of 0.1 C at room temperature. Furthermore, the electrochemical performance of Li2FeSiO4/C at high temperature of 55 °C is also investigated, and it also exhibits a good performance with a discharge specific capacity of 240 mA h g−1at a current rate of 0.2 C.