Alumina’s Effect as Blocking Layer on Self-discharge Process: Case Study of Supercapacitors as Energy storage Devices

Supercapacitors are useful in peak power applications to suppress and compensate transient effects that significantly affect batteries. Unfortunately, they suffer from self-discharge due to the redox reactions process in porous electrodes. This study aims at investigating into the effect of Alumina (Al
₂
O
₃
) as insulating layer (blocking layer) on the supercapacitors' performance during the self-discharge phenomenon. Two models of supercapacitors were developed, and implemented in the Matlab/Simulink software. The first model is without, and the second one with Al
₂
O
₃
coating. Some simulations are performed. The results demonstrate that an application of an ultra-thin insulating layer of Al
₂
O
₃
with a thickness about 0.5 nm on the electrodes of supercapacitors may reduce the faradic reactions rate by 17% and the leakage current by 77.73%. However, the specific capacitance of the electrical double layer may decrease by 45.35% and the voltage drop is about 50% for devices without Al
₂
O
₃
compared to 0.02% with Al
₂
O
₃
.