Lithium storage cell presenting both a high electrical potential and a high lithium insertion capacity

1. Lithium storage cell comprising at least a first electrode comprising an active material wherein Li + cations can be inserted, a second electrode and an electrolyte, wherein the active material comprises a linear condensed compound comprising at least two tetrahedra, respectively of AO 4 and A′O 4 type, bonded by a common oxygen atom and wherein an M 2+ ion of transition metal with a degree of oxidation of +2 is inserted, the ratio between the number of Li + cations able to be inserted in the active material and the number of transition metal ions M 2+ being strictly greater than 1, A and A′ being selected from the group consisting of P 5+ , Si 4+ , Al 3+ , S 6+ , Ge 4+ , B 3+ and M 2+ being selected from the group consisting of Ni 2+ , Co 2+ , Mn 2+ , Fe 2+ and Ti 2+ , wherein

the active material has the following general formula (I):

Li a X b MZ d (A 2 O 7 ) e (A′O 3 ) f   (I)

in which:

X represents at least one alkaline metal with a degree of oxidation of +1 selected from the group consisting of Li + , Na + , K + ,

M represents at least one transition metal with a degree of oxidation of +2 selected from the group consisting of Ni 2+ , Co 2+ , Mn 2+ , Fe 2+ , Ti 2+ ,

Z represents at least one element selected from the group consisting of the metal ions Cu + , Ag + , Mg 2+ , Ca 2+ , Sr 2+ , Zn 2+ , V 2+ , Cu 2+ , Al 3+ , Ti 3+ , Cr 3+ , Fe 3+ , Mn 3+ , Ga 3+ , V 3+ , Ge 4+ , Sn 4+ , Mo 4+ , Ti 4+ , V 4+ , V 5+ , Ta 5+ , Nb 5+ and Mo 6+ , the chemical elements O, S, F and Cl and a group of A″O 4 type,

A″ is a cation selected from the group consisting of P 5+ , Si 4+ , Al 3+ , S 6+ , Ge 4+ , B 3+ ,

a>1,

b and d≧0

and e and f>0.

2. Lithium storage cell according to claim 1 , wherein A″ is identical to A and/or A′.

3. Lithium storage cell according to claim 1 , wherein the active material is in the form of a nano-dispersion of the condensed compound with an electronic conducting additive.

4. Lithium storage cell according to claim 3 , wherein the conducting additive is carbon.

5. Lithium storage cell according to claim 3 , wherein the nano-dispersion also comprises an organic binder.

6. Lithium storage cell according to claim 5 , wherein the organic binder is formed by a polymer selected from the group consisting of methylmethacrylate-based polymers, acrylonitrile-based polymers, vinylidene fluoride-based polymers, polyethers and polyesters.

7. Lithium storage cell according to claim 1 , wherein the second electrode comprises at least one material selected from the group consisting of metal lithium, a lithium alloy, a nano-dispersion of a lithium alloy in a lithium oxide, a material of spinelle structure comprising lithium and titanium, a lithium and transition metal nitride, carbon and a lithium intercalation compound.

8. Lithium storage cell according to claim 1 , wherein the electrolyte is formed by a salt comprising at least the Li + cation.

9. Lithium storage cell according to claim 8 , wherein the salt is selected from the group consisting of LiClO 4 , LiAsF 6 , LiPF 4 , LiR F SO 3 , LiCH 3 SO 3 , LiN(R F SO 2 ) 2 , LiN(R F SO 2 ) 3 , R F being selected from the group consisting of a fluor atom and a perfluoroalkyl group containing between 1 and 8 carbon atoms.

10. Lithium storage cell according to claim 8 , wherein the electrolyte also comprises an aprotic polar solvent in which the salt is dissolved.

11. Lithium storage cell according to claim 10 , wherein the storage cell comprises a separating element designed to be arranged between the first and second electrodes and imbibed with electrolyte.