Well-Dispersed Fluorine-doped Tin Oxide Nanoparticles on the One-Dimensional Network Structure of Carbon Nanofibers for Enabling Ultrafast Lithium Storage

The growing environmental concerns have spurred a surge in the interest in eco-friendly energy storage devices. Because of their advantages, such as high energy density and long cycle life, Li-ion batteries (LIBs) are used in electronic devices and electric vehicles (EVs). However, the specific capacity and ultrafast cycling performance of the LIBs used in EVs require further improvement. In this study, well-dispersed fluorine-doped tin oxide (FTO) nanoparticles (NPs) were deposited on carbon nanofibers (CNFs) using horizontal ultrasonic spray pyrolysis deposition to obtain a CNF/FTO electrode. The F atoms in tin oxide increased its electrical conductivity. The one-dimensional CNF network structure enhanced the electrical conductivity of the electrode. The abundant active sites in nanosized FTO facilitated Li-ion diffusion. The well-dispersed FTO NPs on the CNF matrix prevented the agglomeration of the electrode material and substantial volume changes in the electrode during its cycling. At a current density of 100 mA/g, the CNF/FTO electrode exhibited a superior discharge capacity of 487.96 mAh/g with a capacity retention of 66.7%, and even at an ultrafast current density of 2000 mA/g, it demonstrated excellent performance with a discharge capacity of 289.3 mAh/g and a capacity retention of 93.6% after 500 cycles of operation. Graphical Abstract The well-dispersed fluorine-doped tin oxide nanoparticles on the one dimensional network structure of carbon nanofibers (CNF/FTO) were fabricated by horizontal ultrasonic spray pyrolysis deposition. The CNF/FTO16 electrode showed the highest ultrafast discharge capacity of 289.2 mAh/g and a capacity retention of 93.6% after 500 cycles at current density of 2000 mA/g, which were mainly attributed to the increased active site and prevented agglomeration by well-dispersed FTO NPs on network structure of CNFs.