Iron oxide/graphene composites as negative-electrode materials for lithium ion batteries - optimum particle size for stable performance

We synthesized Fe2O3/graphene composites by a hydrothermal method. The effect of varying the pH in the range pH = 8-12 on the properties of the composites and their performance as negative-electrode materials in lithium ion batteries was investigated. The particle size increased with increasing pH. The best battery performance was obtained for composites prepared at pH = 10 (specific capacity exceeding 800 mA h g(-1) after 60 cycles) due to superior preservation of the electrode morphology compared to samples prepared at lower or higher pH values.