Rechargeable metal or metal-ion cell

1. A rechargeable metal or metal-ion cell comprising:

an anode comprising at least one metal;

a charge-carrying electrolyte comprising a charge carrying medium and at least one metal salt; and

an organic polymer cathode, wherein said cathode comprises at least one N-substituted polyphenothiazine polymer [polymer (P)], said polymer comprising at least one N-substituted phenothiazine recurring unit of formula:

wherein R′ is an electron-withdrawing group comprising at least one heteroatom selected from the group consisting of O, S, P, and N.

2. The cell of claim 1 , wherein in the polymer (P), the R′ group forms with the nitrogen atom of the phenothiazine ring at least one electron-withdrawing group selected from the group consisting of urethane group; urea group; thiourethane group; amide group; sulfonamide groups; sulfinamide group; hydrazine group; phosphonamide group; phosphinimide group; and phosphamide group.

3. The cell of claim 1 , wherein the at least one N-substituted phenothiazine recurring unit of the polymer (P) is a unit having a formula selected from the group consisting of:

wherein each of R, equal to or different from each other and at each occurrence is H or a hydrocarbon group, optionally fluorinated, and optionally comprising one or more ionisable group.

4. The cell of claim 1 , wherein the at least one N-substituted phenothiazine recurring unit further comprises at least one ionisable group selected from the group consisting of carboxylate groups, sulfonate groups, sulfonylimide groups, and phosphonate groups.

5. The cell according to claim 1 , wherein said polymer (P) comprises recurring units selected from the group consisting of:

(I) urethane-containing phenothiazine recurring units of formula:

wherein Rh is a C 1 -C 24 hydrocarbon group, optionally fluorinated, optionally comprising one or more heteroatoms comprised in an additional functional group; and

(II) amide-containing phenothiazine recurring units of formula:

wherein Rf is a C 1 -C 24 hydrocarbon group, optionally comprising one or more heteroatoms comprised in an additional functional group.

6. The cell according to claim 5 , wherein said polymer (P) comprises recurring units of following formula (I-A) and/or recurring units of following formula (II-A):

X in formula (II-A) being a metal.

7. The cell according to claim 1 , wherein the metal ion cell is an alkaline or alkaline-earth secondary battery, wherein the anode comprises a negative electrodes material selected from the group consisting of:

alkaline or alkaline-earth metal;

graphitic carbons able to intercalate an alkaline or alkaline-earth metal;

alkaline or alkaline-earth metal alloy compositions; and

alkaline or alkaline-earth metal titanates, suitable for intercalating an alkaline or alkaline-earth metal with no induced strain.

8. The cell according to claim 7 , wherein said alkaline or alkaline-earth secondary battery is a Lithium-ion cell wherein the anode comprises a negative electrodes material selected from the group consisting of:

graphitic carbons able to intercalate lithium;

lithium metal;

lithium alloy compositions;

lithium titanates;

lithium-silicon alloys; and

lithium-germanium alloys.

9. The cell according to claim 1 , wherein said charge carrying medium is selected from the group consisting of ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl-methyl carbonate, butylene carbonate, vinylene carbonate, fluoroethylene carbonate, fluoropropylene carbonate, gamma-butyrolactone, methyl difluoroacetate, ethyl difluoroacetate, dimethoxyethane, diglyme (bis(2-methoxyethyl)ether), non-protonic ionic liquids, poly(oxyethylene)s, and combinations thereof.

10. The cell according to claim 1 , being a Lithium-ion cell; wherein said at least one metal salt is a lithium salt selected from the group consisting of LiPF 6 ; LiBF 4 ; LiClO 4 ; lithium bis(oxalato)borate; LiN(CF 3 SO 2 ) 2 ; LiN(C 2 F 5 SO 2 ) 2 ; M[N(CF 3 SO 2 )(R F SO 2 )] n with R F being C 2 F 5 , C 4 F 9 , or CF 3 OCF 2 CF 2 , and with M being Li; LiAsF 6 ; LiC(CF 3 SO 2 ) 3 ; and combinations thereof.

11. A N-substituted polyphenothiazine polymer [polymer (P)], comprising at least one N-substituted phenothiazine recurring unit of formula:

wherein R′ is an electron-withdrawing group comprising at least one heteroatom selected from the group consisting of O, S, P, and N.

12. The N-substituted polyphenothiazine polymer according to claim 11 , wherein the N-substituted phenothiazine recurring unit is a unit of formula selected from the group consisting of:

wherein each of R, equal to or different from each other and at each occurrence, is H or a hydrocarbon group, optionally fluorinated, and optionally comprising one or more ionisable groups.

13. The N-substituted polyphenothiazine polymer according to claim 11 , wherein the N-substituted phenothiazine recurring unit further comprises at least one ionisable group selected from the group consisting of carboxylate groups, sulfonate groups, sulfonylimide groups, and phosphonate groups.

14. The N-substituted polyphenothiazine polymer according to claim 11 , comprising recurring units of following formula (I-A) and/or recurring units of following formula (II-A):

X in formula (II-A) being a metal.

15. The cell according to claim 1 , wherein said polymer (P) only comprises recurring units derived from a N-substituted phenothiazine monomer.

16. The cell according to claim 1 , wherein said polymer (P) is manufactured from N-substituted phenothiazine monomer derivatives having halogen group, borane groups, or other labile groups by coupling said N-substituted phenothiazine monomer derivatives.

17. The polymer according to claim 11 , wherein said polymer (P) only comprises recurring units derived from a N-substituted phenothiazine monomer.

18. The polymer according to claim 11 , which is manufactured from N-substituted phenothiazine monomer derivatives having halogen group, borane groups, or other labile groups by coupling said N-substituted phenothiazine monomer derivatives.

19. The polymer according to claim 11 , wherein the N-substituted phenothiazine recurring unit further comprises at least one ionisable group selected from the group consisting of sulfonate groups and sulfonylimide groups.