Defect-rich ultrafine amorphous tin oxyhydroxide nanoparticle anode for high-performance lithium-ion batteries

Abstract

Metal oxyhydroxide nanostructures are attractive anode materials for lithium-ion batteries (LIBs) because of their appreciable theoretical capacity. In their amorphous phase they can greatly relieve volume changes during cycling, enhancing cycle stability. Here, we successfully produce amorphous tin oxyhydroxide nanoparticles (a-SnOOH NPs) with sizes of less than 5 nm using a facile electrochemical anodization method. Plentiful oxygen vacancies (VOs) are generated in the NPs by simply introducing glycerol into the electrolyte. The numerous defects further facilitate the electrochemical kinetics of the a-SnOOH NPs with rich VOs (a-SnOOH/VO NPs), resulting in better cell performance. With the synergetic combination of amorphous nature and abundant defect sites, the a-SnOOH/VO NP anode for LIBs exhibits a considerable initial discharge capacity of 2171.3 mAh/g at a current rate of 0.2 C and retains a high reversible capacity with a coulombic efficiency of 98.4% after 300 cycles. The ultrafine particles also deliver exceptional rate capability with a large capacity of 641.9 mAh/g even at a high current rate of 20 C.