High rate capability and cyclic stability of hierarchically porous Tin oxide (IV)-carbon nanofibers as anode in lithium ion batteries

Tin oxide-carbon composite porous nanofibres exhibiting superior electrochemical performance as lithium ion battery (LIB) anode have been prepared using electrospinning technique. Surface morphology and structural characterizations of the composite material is carried out by techniques such as XRD, FESEM, HR-TEM, XPS, TGA and Raman spectroscopy. FESEM and TEM studies reveal that nanofibers have a uniform diameter of 150-180 nm and contain highly porous outer wall. The carbon content is limited to similar to 10% in the nanofibers as shown by the TGA and EDAX which does not fade the high capacity of SnO2. These nanofibers delivered a higher discharge capacity of 722 mAh/g even after 100 cycles at high rate of 1C. The excellent electrochemical performance can be ascribed to the synergy effect of small amount of carbon in the composite and the hierarchically porous structure which accommodate large volume changes associated with Li-ion insertion-desertion. The porous nano- architecture would also provide a short diffusion path for Li ? ions in addition to facilitating high flux of electrolyte percolation through micropores. The electrochemical performance of composite material has also been tested at 60 degrees C at a higher rate of 2C and 5C. Post cycling FESEM analysis shows no volumetric and morphology changes in porous nanofibers after completing rate capability at high rate of 10C.