The subject hybrid membrane has higher conductivity than the prior arts. This is because the subject membrane has a different host polymer, PVP, which is a more desirable host polymer for H$_{3}$PO$_{4 }$ due to PVP’s extreme high affinity to the acid, thus having a higher uptake of H$_{3}$PO$_{4}$ , leading to a 5 higher conductivity even under low humidity. Also, it forms a very transparent, well dispersed membrane with very few pores. 

In relation to Chen et al. [Chen, N.; Hong, L. Solid State Ionics, 2002, 146, 377], the subject invention uses H$_{3}$PO$_{4 }$ as an extra proton carrier to facilitate the proton conduction and H$_{3}$PO$_{4 }$ is imbedded in the silica network. 

Hence, in the subject invention the host polymer, such as PVP, has a strong interaction with the selected acid, such as H$_{3}$PO$_{4}$ , thus having a large intake of the acid. The acid is immobilized in the interpenetrating network formed by condensation of silica in the membrane to avoid leaching out. The membrane is flexible, transparent, and ductile. Because of a large amount of acid, such as H$_{3}$PO$_{4}$ , already imbedded in the membrane, a small amount of water can significantly facilitates the proton conduction, thus leading to a high conductivity under a low humidity. The conduction mechanism is a proton being transferred between acid molecules or between an acid molecule and a water mo!- ecule or between water molecules in a combination of a Grotthus-type mechanism (i.e., the protons are transferred within adjacent hydrogen bonds) and a vehicular mecha› msm. 

An approach to produce an effective PCM is based on organic-inorganic materials generated by sol-gel and has recently gained increasing interest in view of obtaining new composite compounds with unique properties that result from intimate mixing of various components on a molecular level. In the sol-gel process organic groups are introduced by co-condensation of alkoxides (of silicon, aluminum, tita› nium, zirconium, tin, etc.) with reactive organic functional› ities followed by organic cross-liuking reactions, thus pro› viding the advantages of the polymers, while the inorganic network gives an amorphous structure and good thermal, mechanical and chemical stability. Some of the membranes investigated so far are: 1) NAFION/alkoxide composite membranes, such as, NAFION/SiO$_{2}$-P $_{2}$O$_{5}$-ZrO$_{2 }$ [M. Aparicio, F. Damay, L. C. Klein, "Characterization of SiO2- P2O5-Zr02 sol-gel/NAFION composite membranes", Jour› nal of Sol-Gel Science and Technology, 26(1/2/3) (2003), p. 1055-1059 and Aparicio, M.; Klein, L. C.; Adjemian, K. T.; Bocarsly, A. B., "SiO2-P2O5-Zr02 sol-gel/NAFION com› posite membranes for PEMFC", Ceramic Transactions, 127 (2002), p. 167-176], NAFION/silicon oxide [Jung, D. H.; Cho, S. Y.; Peck, D. H.; Shin, D. R.; Kim, J. S., "Perfor› mance evaluation of a Nafion/silicon oxide hybrid mem› brane for direct methanol fuel cell", Journal of Power Sources, 106 (2002), p. 173-177 and Kim, Haekyoung; Lim, C.; Chang, H., "Fabrications and direct methanol fuel cell applications ofNafion based organic-inorganic hybrid mem› brane", Proceedings-Electrochemical Society (2001 ), 2001-4(Direct Methanol Fuel Cells), p14-28], NAFION/ glass [Nogami, M.; Usui, Y.; Kasuga, T., "Proton conducting organic-glass composites", Fuel Cells, 1 (2001 ), p. 181-185], NAFION/silica [Miyake, N.; Wainright, J. S.; Savinell, R. F., "Evaluation of a sol-gel derived Nafion/silica hybrid membrane for polymer electrolyte membrane fuel cell applications 11. Methanol uptake and methanol perme› ability", Journal of the Electrochemical Society, 148 (2001), A905-A909 and Miyake, N.; Wainright, J. S.; Savinell, R. F., "Evaluation of a sol-gel derived Nafion/silica hybrid membrane for proton electrolyte membrane fuel cell appli- 

cations 1. Proton conductivity and water content", Journal of the Electrochemical Society, 148 (2001), A898-A904], NAFION/TiO$_{2 }$ [Uchida, Hiroyuki; Ueno, Yoshihiko; Hagi- hara, Hiraki; Watanabe, Masahiro, "Self-humidifying elec› trolyte membranes for fuel cells", Journal of the Electro› chemical Society, 150 (2003), A57-A62], NAFION/Cs+ ions [V. Tricoli, "Proton and methanol transport in poly(perfluo› rosulfonate) membranes containing Cs+ and H+ cations", J. Electrochem. Soc. 145 (1998), p. 3798-3801], and NAFION/alkoxides of Ti, Al, Zr and organoalkoxysilanes [V. Tricoli, "Proton and methanol transport in poly(perfluo› rosulfonate) membranes containing Cs+ and H+ cations", J. Electrochem. Soc. 145 (1998), p. 3798-3801]. It was found that the incorporation of inorganic phase in NAFION led to improvements in its thermal stability, reduction of methanol crossover, and higher performance at elevated temperature. However, the proton conductivity in the hybrid membrane was lower than, or equal to, that in unmodified NAFION membranes if the inorganic phase was not P$_{2}$O$_{5 }$ [M. Apari- cio, F. Damay, L. C. Klein, "Characterization ofSiO2-P2O5- Zr02 sol-gel/NAFION composite membranes", Journal of Sol-Gel Science and Technology, 26(1/2/3) (2003), p. 1055-1059, Nogami, M.; Usui, Y.; Kasuga, T., "Proton conducting organic-glass composites", Fuel Cells, 1 (2001), p. 181-185, and Miyake, N.; Wainright, J. S.; Savinell, R. F., "Evaluation of a sol-gel derived Nafion/silica hybrid mem- brane for proton electrolyte membrane fuel cell applications 1. Proton conductivity and water content", Journal of the Electrochemical Society, 148 (2001), A898-A904], which favored proton migration based on the Grotthus-type mecha› nism [T. Yajima and H. Iwahara H. Uchida, "Protonic and oxide ionic conduction in BaCeO$_{3}$-based ceramics---effect of partial substitution for Ba in BaCe$_{0}$ _ $_{9}$O$_{3}$ - with Ca", Solid State Ionics, 47 (1991), p. 117-124, N. Bonanos, B. Ellis, K. S. Knight and M. N. Mahmood, "Ionic conductivity of gadolinium-doped barium cerate perovskites", Solid State Ionics, 35 (1989), p. 179-188, and H. Iwahara, H. Uchida, K. Morimoto, "High temperature solid electrolyte fuel cells using perovskite-type oxide based on barium cerium oxide (BaCeO$_{3}$ )", J. Electrochem. Soc., 137 (1990), p. 462-465]. The studies suggested that inorganic network led to increased close "channel" in film formation, thus decreased the ionic conductivity. 2) Polymer/heteropolyacid composite membranes [Chu, Young-Hwan; Lim, Jung-Eun; Kim, Hyun-Jong; Lee, Chang-Ha; Han, Hak-Soo; Shu!, Yong› Gun, "Proton conducting silica mesoporous/heteropolyacid› PVA/SSA nano-composite membrane for polymer electro› lyte membrane fuel cell", Studies in Surface Science and Catalysis, 146 (2003), (Nanotechnology in Mesostructured Materials), p. 787-790, Honma, I.; Nakajima, H.; Nish› ikawa, O.; Sugimoto, T.; Nomura, S., "Family of High› Temperature Polymer-Electrolyte Membranes Synthesized from Amphiphilic Nanostructured Macromolecules", Jour› nal of the Electrochemical Society, 150 (2003), A616-A619, Honma, Itaru; Nakajima, Hitoshi; Nishikawa, Osamu; Sug› imoto, Toshiya; Nomura, Shigeki, "Proton conducting elec› trolyte membranes synthesized through amphiphilic organic/inorganic hybrid macromolecules", Electrochemis› try (Tokyo, Japan), 70 (2002), p. 920-923, Honma, Itaru; Nakajima, Hitoshi; Nomura, Shigeki, "High temperature proton conducting hybrid polymer electrolyte membranes", Solid State Ionics, 154-155 (2002), p. 707-712, Honma, I.; Nakajima, H.; Nishikawa, O.; Sugimoto, T.; Nomura, S., "Amphiphilic organic/inorganic nanohybrid macromol- ecules for intermediate-temperature proton conducting elec› trolyte membranes", Journal of the Electrochemical Society, 149 (2002), A1389-A1392, Honma, I.; Nishikawa, O.; Sug- 

