A comparison between growth of direct and pulse current electrodeposited crystalline SnO2 films; electrochemical properties for application in lithium-ion batteries

Tin oxide (SnO₂) films were electrodeposited on graphite substrates using direct and pulse current electrodeposition techniques. The influence of applied current density on the morphological properties, crystal structure, and electrochemical behavior of the resulting films were studied by scanning electron microscope, X-ray diffraction spectroscopy, Mott–Schottky analysis, cyclic voltammetry, and electrochemical impedance spectroscopy techniques. The results showed that pulse electrodeposited films have porous flower-like morphology with smaller crystallite size and high donor density in comparison with direct current electrodeposited films that include equiaxed particles in their morphologies, such characteristics give them better electrochemical performance (higher degree of reversibility, higher specific capacitance, and faster lithium-ion diffusion) than those films that were synthesized by conventional direct current electrodeposition method. Furthermore, using higher applied current densities leads to the improvement of SnO₂ films’ electrochemical performance due to the formation of the films with finer morphology that include more porosity and oxygen vacancies in their respective crystal structure.