Clean preparation of Fe2SiO4 coated Fe2O3 integrated with graphene for Li-ion storage application

Ferric oxide (Fe 2 O 3 ) is an attractive candidate for energy storage applications, including anode of Li-ion batteries due to its low-cost, high availability and large theoretical capacity. However, the mineral suffers from poor cyclability and rate performance due to the combination of rapid disintegration of the compound upon Li-ion insertion and extraction cycles, and poor conductivity of the electrode. Here, for the first time, we report on the clean modification of ferric oxide using corn-derived silica and graphite-derived graphene nanosheets , using a facile calcination-mechanical integration approach, without the involvement of environmentally-problematic raw materials. The product (Fe 2 O 3 @Fe 2 SiO 4 @G) consists of ferric oxide particles coated with iron silicate; and these hybrid particles are integrated with graphene nanosheets. The presence of Fe 2 SiO 4 layers could relieve the volume changes of Fe 2 O 3 involved in the cycling, and also improves the ionic conductivity reducing the interfacial resistance between the electrode and the electrolyte, while graphene nanosheets improves the electrical conductivity of the electrode. Thus Fe 2 O 3 @Fe 2 SiO 4 @G electrode considerably outperforms the initial Fe 2 O 3 with outstanding Li-ion storage capacities of 823 and 422 mA h g −1 recorded at the current densities of 100 and 1000 mA g −1 , respectively, after 300 cycles. Pseudocapacitive behavior of the electrode is found to be 76.6% at 1 mV s −1 , confirming the promotion of surface interactions in the nanostructured hybrid material . This article suggests a clean way of modifying naturally occurring Fe 2 O 3 to be used as the anode of lithium ion batteries.