Li2CoSiO4 has been prepared successfully by a solution route or hydrothermal reaction for the first time, and its electrochemical performance has been investigated primarily. Reversible extraction and insertion of lithium from and into Li2CoSiO4 at 4.1V versus lithium have shown that this material is a potential candidate for the cathode in lithium ion batteries. At this stage reversible electrochemical extraction was limited to 0.46 lithium per formula unit for the Li2CoSiO4/C composite materials, with a charge capacity of 234mAhg−1 and a discharge capacity of 75mAhg−1.