Facile synthesis and enhanced electrochemical performance of Li2FeSiO4/C/reduced graphene oxide nanocomposites

Li2FeSiO4/amorphous carbon/reduced graphene oxide (LFS/C/rGO) was synthesized from nano-SiO2, rGO, Li2CO3, FeC2O4·2H2O and ammonium citrate by a facile solid-state reaction method. Electrical conductivity tests and charge-discharge voltage profiles indicate LFS/C/rGO with 20 wt.% rGO shows the highest electrical conductivity and highest discharge capacity of 191.6 mAh g−1. XRD results reveal rGO can promote the Li2FeSiO4 crystalline grain growing, especially the (210) crystal face growing. SEM results indicate a more valid conductive network is formed in LFS/C/rGO. TEM image shows the good crystalline of LFS in LFS/C/rGO composite. FT-IR spectrum indicates that 1638 cm−1 peak of rGO's C = C bonds are observed in LFS/C/rGO and all typical characteristic absorption peaks of LFS/C/rGO exhibit blue shifts compared to that of LFS/C. The electrochemical measurements illustrate that LFS/C/rGO has much better electrochemical performance than that of LFS/C. The main reason might be attributed to the more valid conductive network formed by amorphous carbon and rGO.