On the other hand, most of the inorganic-organic composite membranes studied so far have a mass ratio of about 10-15 wt.% , , . In addition, few inorganic-organic composite membranes synthesized have well-connected proton pathways , , , , , , . Therefore, the ZrP membrane fabricated in this study is of great importance. There is also a remarkable discovery: three types of inorganic particles, ZrP/ZrATMP/ZrHEDP, can be packed into the substrates at a high concentration of about 48 wt.% with the same technique. It is expected that various ZrP-based inorganic particles can be packed into the substrate by converting Acac-Zr. As we mentioned in the introduction, those inorganic particles have a variety of possible applications. Even if the application is not for PEM, the phase-separated structure is beneficial because the structure does not leave isolated inorganics and maximizes its properties. The presented method can easily be applied to fill a large amount of multiple inorganic particles with continuous structure.