Fluorine-doped tin oxide microspheres with 3D tunneled porous structure and nanocarbon skin for ultrafast and highly stable lithium-ion battery

The advancement of high-performance lithium-ion storage is critical to meet growing demands of the global energy market, especially electric vehicles (EVs). The ultrafast charging capabilities of traditional graphite anodes are limited by their inadequate lithium storage kinetics and relatively low theoretical capacity (372 mAh/g). Hence, we developed fluorine-doped tin oxide (FTO) microspheres with the 3D tunneled porous structure and nanocarbon skin. This unique carbon-coated porous (CPFTO) structure was successfully developed via one-pot vertical ultrasonic spray pyrolysis using a mixed solvent with different boiling points and Ketjen black. The electrode of CPFTO reveals remarkable specific capacity of 839.8 mAh/g with 78.3 % retention after 100 cycles at 100 mA/g and outstanding ultrafast cyclic stability with 77.3 % retention and 410.6 mAh/g after 500 cycles at 3000 mA/g. These performance gains resulted from the (i) higher number of electrochemically active sites and increased ion and electron conductivities provided by the 3D porous structure and the nanocarbon skin and (ii) minimized volume expansion of FTO by the nanocarbon skin. This study demonstrates that the advanced structural design of CPFTO effectively addresses the challenges of ultrafast lithium storage and offers a promising solution for next-generation LIBs.