Developing the supercapacitor device with low cost, non-toxic, efficient, and high electrochemical activity is the key role of the electrode material. Owing to the open framework structure with enhanced ionic conductivity, the metal phosphate based electrode materials are preferred for the supercapacitor application. Herein, in this report Ammonium Oxonium Dodeca Molybdophosphate (NH₄)_2.6(H₃O)_0.4(PMo₁₂O₄₀) open channel microcubes are synthesized using simple co-precipitation method, which enables to produce the maximum specific capacitance of 752 F g⁻¹ at a current density of 2 A g⁻¹.