*3.3. Simulation Results of EBMD Model*

Figure 6 depicts the variation in the distributions of space charges, electric fields, molecular chain displacements, and electron energies with time in pure LDPE and LDPE/Al2O3 nanodielectrics. With the increase in nanofiller content, under the same voltage, the accumulation of space charges in the nanocomposites first decreases and then increases, while the electric field concentration first decreases and then increases. It can be obtained from the dynamic equation of molecular chain motion that, with the increase in nanofiller content, the displacement of molecular chains within nanocomposites first decreases and then increases under the same voltage. This causes the energy accumulated by the electrons to decrease first and then increase. At the same time, it is considered that the trapping ability of deep traps in nanocomposites first increases and then decreases. The energy accumulation of charge carriers in the dynamic free volume and the trapping ability of deep traps together determine the breakdown electric field of nanodielectrics as a function of nanofiller content. With the increase in the mass percentage of nanofillers, the breakdown electric field of the nanodielectrics increased first and then decreased.

**Figure 6.** Distributions of space charges (**a1**–**a5**), electric fields (**b1**–**b5**), molecular displacements (**c1**–**c5**), and electron energy gains (**d1**–**d5**) in pure LDPE and LDPE/Al2O3 nanocomposites with nanofiller contents of 0.1 wt%, 0.5 wt%, 2.0 wt%, and 5.0 wt%.
