Abstract: The invention relates to a class of electrochemical energy storage materials and a preparation method and application thereof. A porous metal oxide-based electrochemical energy storage material at least comprises a host metal oxide with a hierarchical pore structure; wherein, the host metal oxide is a single crystal, quasicrystal, or twin crystal structure with ordered atomic lattice arrangement, the crystal is rich in oxygen atom vacancy defects, the structural general formula is MxOy?z, wherein M is selected from one or more combinations of niobium element, molybdenum element, titanium element, vanadium element, manganese element, iron element, cobalt element, nickel element, copper element, zinc element, tungsten element, tantalum element, and zirconium element; and 1?x?2, 1?y?5, and 0.1?z?0.9, preferably Nb2O5?z.