Synergic Effect of Niobium Doping and Carbon Coatingon the Performance of a Li₂ZnTi₃O₈ Anode Candidate for Lithium Ion Batteries

This study designates the outcomes of niobium doping and carbon coating on the structural and electrochemical performance of Li2ZnTi3O8 as an anode electrode for use in Li-ion batteries. Nb-doped, carbon-coated Li2ZnTi2.95Nb0.05O8/C (LZTO-2) and pristine Li2ZnTi3O8 (LZTO-1) anode materials were synthesized using facile sonication-assisted solid-state synthesis using sucrose as the carbon source. The synthesized materials are characterized using X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Electrochemical investigations are carried out using galvanostatic cycling, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). Structural analysis shows that the synthesized materials crystallize in the P4332 space group. It is observed through these studies that Nb doping (5%) and carbon (10%) coating have improved significantly the electrochemical performance of the (LZTO-2) as compared to (LZTO-1). LZTO-2 exhibits excellent cyclic performance and specific capacity (mA h g–1) at all C-rates. The excellent specific capacity of LZTO-2 at higher C-rates (5C, 10C, 20C, and 30C), i.e., 156, 135, 113, and 77 mA h g–1, respectively, as compared to LZTO-1, i.e., 127, 89, 48, and 26 mA h g–1, respectively, can be attributed to low charge transfer resistance resulting from having the proper amount of dopant and carbon content. Higher specific capacities, low charge transfer resistance, and higher values of Li-ion diffusion coefficient indicate that LZTO-2 is a magnificent anode electrode for commercial Li-ion batteries.