Synthesis and electrochemical behavior of Li2CoSiO4 cathode with pyrrolidinium-based ionic liquid electrolyte for lithium ion batteries

Li2CoSiO4, a silicate olivine cathode for lithium rechargeable batteries, is synthesized for the first time by sol-gel method using polyacrylic acid (PAA) as the chelating agent. Coupled thermal and vibrational analysis of the gel and also the X-ray diffraction pattern confirms the formation of the sample at 800 A degrees C. 1-Butyl-1-methyl pyrrolidinium bis(trifluoromethanesulfonyl)imide (BMPyTFSI) solutions of lithium bis(trifuloromethansulfonyl)imide (LiTFSI) having a concentration of 0.2 mol kg(-1) is used as electrolyte. The electrochemical stability window of this electrolyte is found to be > 5 V by linear sweep voltammetry technique. The compatibility of Li2CoSiO4 with 0.2 mol kg(-1) LiTFSI-BMPyTFSI electrolyte is tested by charge-discharge cycles which show charging and discharging capacities of about 204 and 32 mAh g(-1), respectively, in the first cycle.