Kinetically limited de-lithiation behavior of nanoscale tin-covered tin oxidenanowires

Abstract

In this paper, we report that Sn-nanocluster-covered SnO₂ nanowire (“hybrid architectures”) electrodes exhibited stage-wise de-lithiation suggesting complete lithium extraction. The lithiation and de-lithiation behavior explains that the high capacity retention of 814 mAh g⁻¹ and durability over hundred cycles is because of low irreversible capacity loss. Mono-layers of un-agglomerated, sub 60 nm size Sn clusters supported on metallic electrodes also exhibited similar stage-wise de-lithiation while the microscale Sn clusters exhibited single-phase lithium extraction. This can be attributed to shorter lithium ion diffusion lengths and high surface area of the nanomaterials. The cyclic voltammetric studies of Sn nanoclusters (sub 60 nm size) confirm the reaction kinetics limited behavior of lithiation and de-lithiation characteristics. The Sn-nanocluster-covered SnO₂ nanowires showed a capacity retention of 458 mAh g⁻¹ at 500 mAg⁻¹ current density indicating an excellent rate capability.