Cathode materials for secondary (rechargeable) lithium batteries

A cathode material for a rechargeable electrochemical cell, said cell also comprising an anode and an electrolyte, the cathode material comprising an ordered or modified olivine compound having the formula:

• Lix+yM1−(y+d+t+q+r)DdTtQqRr[PO4]1−(p+s+v)[SO4]p[SiO4]s[VO4]v
• where
• M is Fe2+ or Mn2+ or mixtures thereof;
• D is a metal in the +2 oxidation state selected from the group consisting of:
• Mg2+, Ni2+, Co2+, Zn2+, Cu2+, and Ti2+;
• T is a metal in the +3 oxidation state selected from the group consisting of:
• Al3+, Ti3+, Cr3+, Fe3+, Mn3+, Ga3+, Zn3+, and V3+;
• Q is a metal in the +4 oxidation state selected from the group consisting of:
• Ti4+, Ge4+, Sn4+, and V4+;
• R is a metal in the +5 oxidation state selected from the group consisting of:
• V5+, Nb5+, and Ta5+;
• 0≦x≦1;
• 0≦y, d, t, q, r, p, s, v≦1 where at least one of y, d, t, q, r, p, s, and v differ from 0 and
• y+d+t+q+r≦1;
• p+s+v≦1;
• 3+s−p=x−y+2+t+2q+3r;
• where x is the degree of intercalation during operation of the electrode material, y represents the fraction of lithium ions on the initial Fe2+ and/or Mn2+ sites;
• d represents the fraction of divalent ions (noted as D) on the initial Fe2+ and/or Mn2+ sites;
• t represents the fraction of trivalent ions (noted as T) on the initial Fe2+ and/or Mn2+ sites;
• q represents the fraction of tetravalent ions (noted as Q) on the initial Fe2+ and/or Mn2+ sites;
• r represents the fraction of pentavalent ions (noted as R) on the initial Fe2+ and/or Mn2+ sites;
• p represents the fraction of hexavalent sulfur (as discrete SO42− tetrahedra) on the initial P5+ sites;
• s represents the fraction of tetravalent silicon (as discrete SiO4 tetrahedra) on the initial P5+ sites;
• and v represents the fraction of pentavalent vanadium ions on the initial P5+ sites, and M, D, T, Q and R reside in octahedral sites.

A cathode material for a rechargeable cell based on iron phosphate and/or manganese phosphate, said cell comprising an anode and an electrolyte, said cathode material comprising ordered or modified olivine Lix+yM1−(y+d+t+q+r)DdTtQqRr[XO4] wherein:

• Li is localized in linear chains of alternate planes of octahedral sites in the olivine structure or in partial substitution of the M atoms occupying zigzag chains of octahedra;
• M comprises Fe2+ or Mn2+ metal or mixtures thereof localized in the zigzag chains of octahedra;
• D comprises a metal atom in the +2 oxidation state in substitution on an M atom octahedral crystallographic site;
• T comprises a metal atom in the +3 oxidation state in substitution on an M atom octahedral crystallographic site;
• Q comprises a metal atom in the +4 oxidation state in substitution on an M atom octahedral crystallographic site;
• R comprises a metal atom in the +5 oxidation state in substitution on an M atom octahedral crystallographic site;
• XO4 comprises covalently bounded tetrahedral oxide anions that are either PO43− or PO43− partially substituted by other covalently bounded tetrahedral oxide isovalent or aliovalent anions;
• 0≦x≦1;
• 0<y+d+t+q+r<1, where y, d, t, q, or r may vary between 0 and 1 with at least one of y, d, t, q, r differ from 0, wherein:
• x is a degree of intercalation during operation of the electrode material;
• y represents the fraction of lithium ions on the initial M sites;
• d represents the fraction of divalent ions on the initial M sites;
• t represents the fraction of trivalent ions on the initial M sites;
• q represents the fraction of tetravalent ions on the initial M sites;
• and
• r represents the fraction of pentavalent ions on the initial M sites.