Abstract : The EMI shielding performance and energy storage properties of the α-MnO2 SQDs are modulated by incorporating cobalt ions into crystal structure and results are verified through theoretical analysis. All the inherent properties are scrutinised using Reitveld refinement with simulated X-ray and DFT techniques. Besides cDFT/cRPA, PBE generalized GGA+U exchange correlation is used based on FM and different AFM configurations by avoiding SIE. Therefore, this theory can predict the superiority in EMI shielding and supercapacitive performance.