Carbon-enhanced electrodeposited SnO₂/carbon nanofiber composites as anode for lithium-ion batteries

Tin oxides (SnO₂) are promising anode material candidate for next-generation lithium-ion batteries due to their high capacity, low cost, high abundance, and low toxicity. However, the practical use of SnO₂ anodes is currently limited by their large volume changes during cycling. Severe volume changes of SnO₂ anodes lead to intense pulverization and loss of electrical contact between the active material and carbon conductor. Herein, we introduce binder-free SnO₂-electrodeposited carbon nanofibers (CNF@SnO₂) and SnO₂-electrodeposited porous carbon nanofibers (PCNF@SnO₂) composites that can maintain their structural stability during repeated charge-discharge cycling. Results indicated that the amount of the electrodeposited SnO₂ nanoparticles and the capacity of the resultant composites were successfully enhanced by using a porous nanofiber structure. Both CNF@SnO₂ and PCNF@SnO₂ composites were also coated with amorphous carbon layers by chemical vapor deposition to further improve the structural stability. Electrochemical performance results demonstrated that the combination of porous nanofiber structure and CVD amorphous coating led to a novel carbon-coated PCNF@SnO₂ composite anode with high capacity retention of 78% and large coulombic efficiency of 99.8% at the 100th cycle.