Syntheses, properties and applications of framework titanium phosphates with open structures
A new layered hydrogen titanium phosphate (HTP) was synthesized by ion exchange of a precursor material NMe[sub 4]TP. This precursor, which was prepared from a hydrothermal reaction employing tetramethylammonium as a templating cation, also has a layered structure. The chemical formula of HTP was proposed as TiO[sub 2](H[sub 2]PO[sub 4])(H[sub 3]O). This was derived using [sup 31]P magic angle spinning solid state NMR, structural considerations, and other supplemental methods. A model for the structure of HTP was proposed in this study. HTP is capable of undergoing amine and redox lithium intercalations and the reactions show excellent reversibility. Each formula unit of HTP can take up one amine molecule or two lithium cations. Amines intercalate into HTP can take up one amine molecule or two lithium cations. Amines intercalate into HTP with a bilayer conformation and tilt at an angle of about 55 degrees relative to the layer slabs. Metal cations can also be incorporated into HTP under carefully controlled pH conditions or from the amine intercalates. The conductivity of the lithium cations intercalated into HTP was studied by ac impedance spectroscopy and is comparable to that of the NASICON type compounds. A Li/LiClO[sub 4]/HTP electrochemical cell was constructed and its discharge was studied. The discharge potential ranges between 2.6 and 1.8 volts and the energy density of this cell was estimated to be about 550 W[sup *]h/kg for the pure HTP material. The three dimensional titanium phosphates with the NASICON structure were also studied in this work. The hydrothermal process was used and investigated for the synthesis of MTi[sub 2](PO[sub 4])[sub 3], where M = Li[sup +], Na[sup +], K[sup +], Ag[sup +], or Cu[sup +]. Pure products were obtained under milder conditions than reported before. A comparison on the synthesis and properties of these NASICON compounds prepared from different processes is given.
- Research Organization:
- State Univ. of New York, Binghamton, NY (United States)
- OSTI ID:
- 6973659
- Resource Relation:
- Other Information: Thesis (Ph.D.)
- Country of Publication:
- United States
- Language:
- English
Similar Records
One-step hydrothermal synthesis and electrochemical performance of sodium-manganese-iron phosphate as cathode material for Li-ion batteries
V[sub 2](PO[sub 4])[sub 3]: A novel NASICON-type vanadium phosphate synthesized by oxidative deintercalation of sodium from Na[sub 3]V[sub 2](PO[sub 4])[sub 3]
Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
36 MATERIALS SCIENCE
TITANIUM PHOSPHATES
MOLECULAR STRUCTURE
SYNTHESIS
ELECTROCHEMISTRY
CHEMISTRY
OXYGEN COMPOUNDS
PHOSPHATES
PHOSPHORUS COMPOUNDS
TITANIUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
400201* - Chemical & Physicochemical Properties
360601 - Other Materials- Preparation & Manufacture