Process for Producing Defect-Free Lithium Metal Phosphate Electrode Materials

A method of manufacturing a defect-free phospho olivine based lithium insertion-type electrode, comprising:

• providing an aqueous solutions of Li+, Mn+, and PO43− in a reactor, wherein Mn+ is one or more single or a mixed transition metal selected from the group consisting of Fe2+, Fe3+, Mn2+, Co2+, Ni2+, Mg2+, and Zn2+;
• heating the solution in the reactor to about 150° C. to 220° C. under elevated pressure 100-3000 psi for about 3 to 10 hours to produce a phospho-olivine having a formula LiMxPO4 where 0<x≦1, with varying degree of defects due to a presence of M metal in lithium sites of the phospho-olivine structure;
• recovering the produced phospho-olivine as a powder;
• heating the phospho-olivine powder to a transition temperature in an inert or reducing atmosphere, thereby forming a defect-free phospho-olivine structure, and
• mixing the defect-free phospho-olivine with a conducting additive to produce the defect-free phospho olivine based lithium insertion-type electrode.

A defect-free phospho-olivine composition prepared by a process, comprising:

• providing an aqueous solutions of Li+, Mn+, and PO43− in a reactor, wherein Mn+ is one or more single or a mixed transition metal selected from the group consisting of Fe2+, Fe3+ Mn2+, Co2+, Ni2+, Mg2+, and Zn2+;
• heating the solution in the reactor to about 150 to 220° C. under elevated pressure 100-3000 psi for about 3 to 10 hours to produce a phospho-olivine having a formula LiMxPO4 where 0<x≦1, with varying degree of defects due to a presence of M metal in lithium sites of the phospho-olivine structure;
• recovering the produced phospho-olivine as a powder;
• and
• heating the phospho-olivine powder to a transition temperature in an inert or reducing atmosphere, thereby forming the defect-free phospho-olivine structure.

A method of synthesizing a defect-free phospho-olivine composition, comprising:

• providing a slurry of Li+, Mn+, and PO43− in a one-pot in-situ reactor, wherein Mn+ is one or more single or a mixed transition metal selected from the group consisting of Fe2+, Fe3+, Mn2+, Co2+, Ni2+, Mg2+, and Zn2+;
• heating the slurry in the reactor to about a first reaction temperature where a phospho-olivine crystal lattice having a formula LixMPO4 where 0<x≦1, with varying degree of defects due to a presence of M-type metal in lithium sites forms under autogenous pressure;
• heating the formed phospho-olivine crystal lattice in the reactor to about a second reaction temperature, which defines the onset of cation ordering;
• holding the second reaction temperature until a desired defect concentration is reached;
• and
• recovering the produced defect-free phospho-olivine.

A defect-free phospho-olivine composition prepared by a process, comprising:

• providing a slurry of Li+, Mn+, and PO43− in a one-pot in-situ reactor, wherein Mn+ is one or more single or a mixed transition metal selected from the group consisting of Fe2+, Fe3+, Mn2+, Co2+, Ni2+, Mg2+, and Zn2+;
• heating the slurry in the reactor under autogenous pressure;
• monitoring the slurry in the reactor by in situ x-ray diffraction to determine a first temperature where a phospho-olivine crystal lattice having a formula LixMPO4 where 0<x≦1 forms;
• heating the formed phospho-olivine crystal lattice in the reactor;
• monitoring the formed phospho-olivine crystal lattice in the reactor by in situ x-ray diffraction to determine an onset of cation ordering;
• holding the temperature until a desired defect concentration is reached;
• and
• recovering a defect-free phospho-olivine.