Rechargeable electrochemical battery cell

1. A rechargeable lithium ion battery cell, comprising:

a housing, a positive electrode, a negative electrode and an electrolyte, wherein the electrolyte comprises SO 2 and a conductive salt and contains less than 50% by weight of organic material:

wherein the positive electrode comprises a quantity of active material per unit area of at least 30 mq/cm2;

wherein the positive electrode comprises a compound of the formula Li x M′ y (XO 4 ) a F b (I), which compound is optionally doped, wherein

M′ is at least one metal selected from the group consisting of the elements Ti, V, Cr, Mn, Fe, Co, Ni, Cu and Zn,

X is selected from the group consisting of the elements P, Si and S,

x is greater than 0,

y is greater than 0,

a is greater than 0 and

b is greater than or equal to 0, and

wherein the sum of positive charges in the compound equals the sum of negative charges.

2. The battery cell according to claim 1 , wherein the positive electrode further comprises a current collector having a first portion comprising a porous metal which has first and second surfaces and a thickness extending between the first and second surfaces, the porous metal comprising a plurality of pores extending at least partially through the thickness and containing the compound, wherein at least some of the pores have void spaces accessible to the electrolyte.

3. The battery cell of claim 2 , wherein the plurality of pores further contains at least one of a conductive agent, a binding agent, and a lithium halogenide.

4. The battery cell of claim 2 , wherein at least some of the pores extend through the entire thickness.

5. The battery cell of claim 2 , wherein the current collector further comprises a second portion in conductive contact with the first portion, the second portion comprising a connector.

6. The battery cell of claim 1 , wherein the positive electrode has a thickness of at least 0.25 mm.

7. The battery cell of claim 1 , wherein the positive electrode has a thickness of from 0.25 mm to 1.0 mm.

8. The battery cell according to claim 1 , wherein the positive electrode comprises a quantity of active material per unit area of from 30 mg/cm 2 to 180 mg/cm 2 .

9. The battery cell according to claim 8 , wherein the positive electrode comprises a binding agent in an amount of no more than 10 wt. % of the active material.

10. The battery cell according to claim 1 , wherein the positive electrode is porous and has a porosity of no more than 50%.

11. The battery cell according to claim 1 , wherein the negative electrode has a thickness of at least 0.2 mm.

12. The battery cell according to claim 1 , wherein the negative electrode has a thickness of from 0.2 mm to 0.8 mm.

13. The battery cell according to claim 1 , wherein the negative electrode comprises carbon for inserting lithium ions.

14. The battery cell according to claim 1 , wherein the negative electrode comprises a quantity of active material per unit area of at least 10 mg/cm 2.

15. The battery cell according to claim 1 , wherein the negative electrode comprises a quantity of active material per unit area of from 10 mg/cm 2 to 100 mg/cm 2 .

16. The battery cell according to claim 1 , wherein the negative electrode is porous and its porosity is no more than 50%.

17. The battery cell according to claim 1 , wherein the negative electrode comprises a porous metal portion and binding agent contained therein and the binding agent is in an amount of no more than 5 wt. % of the weight of the porous metal portion of the negative electrode.

18. The battery cell according to claim 1 , wherein the cell discharge capacity does not decrease by more than 25 percent between the 100 th and 350 th cycles of charging and discharging.