Mesoporous lithium metal phosphates are an important class of materials for the development of lithium ion batteries. However, there is a limited success in producing mesoporous lithium metal phosphates in the literature. Here, a lyotropic liquid crystalline (LLC) templating method was employed to synthesize the first examples of LiMPO4 (LMP) of Mn(II), Co(II), and Ni(II). A homogeneous aqueous solution of lithium and transition metal nitrate salts, phosphoric acid (PA), and surfactant (P123) can be spin coated or drop-cast coated over glass slides to form the LLC mesophases which can be calcined into mesoporous amorphous LMPs (MA-LMPs). The metal salts of Mn(II), Co(II) and Ni(II) produce MA-LMPs that crystallize into olivine structures by heat treatment of the LLC mesophase. The Fe(II) compound undergoes air oxidation. Therefore, both Fe(II) and Fe(III) precursors produce a crystalline Li3Fe2(PO4)3 phase at over 400 °C. The MA-LMPs show no reactivity towards lithium, however the crystalline iron compound exhibits electrochemical reactivity with lithium and a good electrochemical energy storage ability using a lithium-ion battery test.
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We would like to thank to beam line scientist, Dr. M. Harfouche (from SESAME), Mr. K. E. Ercan and Ms. I. Karakaya for their helps in XANES and Mr. M. Güler for TEM measurements. We also thank to TÜBİTAK (under the project number 215Z193) for the financial support of this work and Turkish Atomic Agency for the travel grant for the XANES measurements. This work was also performed in part at the Queensland node of the Australian National Fabrication Facility, a company established under the National Collaboration Research Infrastructure Strategy to provide nano and microfabrication facilities for Australia's researchers. Ö.D. is a member of the Science Academy, Istanbul, Turkey.
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