Electrolytic reduction is a crucial process during the pyroprocessing of oxide spent fuel. This paper investigates the effects of different concentrations of Li

2

O on the properties of the LiCl-UCl

3

-Li

2

O molten salt system during electrolytic reduction using first-principles molecular dynamics simulations. The study reveals that increasing Li

2

O concentration lowers the ion diffusion coefficients of Li

+

Cl

-

and O

2-

in the electrolyte

which has negative effect on the transport property of the system. A thorough analysis of the ligand structures formed by various components in the molten salt was conducted

including radial distribution functions and angular distribution functions. The analysis reveals that oxygen ions compete with chloride ions for coordination with cations. This competitive interaction has a significant impact on the coordination between Li-Cl and U-Cl elements

thereby influencing the microstructure. The analysis of electronic structures shows that the addition of Li

2

O affects the charge transfer among lithium

uranium

and chlorine

impacting the bond strength between anions and cations. Finally

the calculation of redox potential shows that an appropriate concentration of Li

2

O is beneficial to the electrochemical reduction process. The research results provide a theoretical basis for the design of molten salts in the electroly

tic reduction process.