Binderless, bendable graphene/Fe_xSn_1-xO₂ anode for lithium-ion batteries without the necessity of a current collector

SnO₂ is an appealing anode material for lithium ion batteries. Advantages of SnO₂ includes relatively low charge-discharge plateau and highly abundance in nature. However, the volume change (300%) is significant and critically impeding its cycle life. In this manuscript, we address these problems by exploiting an in-situ redox process to prepare graphene encapsulated SnO₂ nanoparticles using soluble Sn²⁺ as the Sn precursor, which is oxidized to SnO₂ by using graphene oxide. This method affords graphene @ SnO₂ via oxygen bridging through of SnO₂ nanoparticles. Furthermore, this method incorporates Fe atom into the SnO₂ structure in-situ to create Fe_xSn_1-xO₂ structure, which exhibits higher Li storage capacity. Our synthetic approach delivers graphene encapsulated Fe_xSn_1-xO₂ structure, which is located on flexible carbonaceous fibers, and the whole system can be applied as lithium-ion batteries anode without any need of a current collector or binder polymer. This novel Sn based electrode could deliver a high capacity (calculate total electrode mass) of 454.3 mAh g⁻¹ after 200 cycles at 100 mA g⁻¹ (65.1% retention). Unlike most contemporary technologies, increasing the thickness of our Sn based electrode simply increases the capacity proportionally. The areal capacity is 1348.3 μAh cm⁻², and it is simply doubled to 2856.1 μAh cm⁻² while we double the thickness of electrode.