Catalytic effect of reduced graphene oxide on facilitating reversible conversion reaction in SnO2 for next-generation Li rechargeable batteries

With growing needs for mobility and wearable devices, developing advanced electrode materials for next-generation Li rechargeable batteries becomes one of the major challenges. To resolve this issue, various types of metal oxide materials have been adopted as high-capacity anode materials. In this work, a high-energy SnO2-based anode material is proposed by combinative hybridization with reduced graphene oxide, which is an efficient method to improve electrochemical performance of Li-ion battery. As a result, the Li storage performance of SnO2 and reduced graphene oxide composite electrode is remarkably enhanced in terms of reversible capacity, cyclability and rate capability. Synchrotron-based X-ray analysis has revealed that the improvement in electrochemical performances can be attributed to high and stable participation of additional conversion reaction as well as alloying reaction of SnO2 along with insertion reaction of reduced graphene oxide. In this composite electrode, we observe catalytic effect of reduced graphene oxide that improves reversibility of conversion reaction by reducing Sn–O bond strength, in addition to providing stable matrix. The information from this work will give insights into how the changes of physicochemical properties in graphene composite materials affect the electrochemical performance of electrode material and thus, provide a realizable strategy for next-generation rechargeable batteries. •High-performance SnO2/rGO composite electrode is prepared by a facile method.•The conversion reaction occurs more reversibly by introducing rGO.•Charge transfer between carbon and SnO2 induce weaker Sn–O bond strength.•The catalytic effect of rGO on conversion reaction is due to the weakened Sn–O bond.