Experimental and theoretical studies on dynamic properties of Li ions in LixMn2O4

In order to study the dynamic properties of LixMn2O4, potential relaxation techniques (PRT) is used to measure the chemical diffusion coefficient of LixMn2O4. Results are presented for x ranges from x=0.1 to 0.9. They show that the chemical diffusion coefficient at the two-phase coexistent stage near x=0.3 and 0.7 is higher than at the single-phase stage during the insertion and extraction process. Monte Carlo (MC) simulations are also used to simulate the ionic conductivity σ of Li ions in LixMn2O4 and its dependence as a function of lithium concentration x. The results show an M shaped curve in the plot of ionic conductivity σ versus x when the simulation temperature is 293 K, which confirms the experimental PRT results. The voltage profiles of LixMn2O4/Li cells were also simulated with different boundary conditions.