Facile synthesis and lithium reversible insertion on iron hydrated trifluorides FeF3·0.5H2O

•Simple and low cost synthesis process for transition metal fluorides.•Hydrated iron trifluorides FeF3·0.5H2O synthesized via solvothermal route for the first time.•The composite iron trifluorides-graphene is showing better electrochemical performance.•The composite FeF3·0.5H2O/graphene is showing enhanced capacity of 200 mAh/g.

An original synthesis method for the synthesis of hydrated iron trifluorides is presented for the first time. This method, based on solvothermal process starting from iron salt and HF in alcool, is economic, simple and environmentally benign. The electrochemical performances of the composite phase FeF3·0.5H2O/graphene is showing enhanced capacity of 200 mAh/g at C/20.