Use of reactive ionic liquids as additives for electrolytes in secondary lithium ion batteries

1. A compound of formula (I)

wherein

X is N or P;

—SO 3 — is —O—S(O) 2 — or —S(O) 2 —O—;

R 3 is C 1 -C 10 alkyl, C 2 -C 10 alkenyl, C 2 -C 10 alkynyl, C 6 -C 12 aryl, and C 7 -C 24 aralkyl, which may be substituted by one or more groups selected from F, cyclopropyl, 1,2-epoxyethyl, and sulfonate, and wherein one or more CH 2 groups of alkyl, alkenyl, alkynyl and aralkyl which are not directly bound to the X-atom may be replaced by O, 1,2-epoxyethylene, cyclopropylene or SO 3 ;

R 1 and R 2 are linked and jointly selected from —(CH 2 ) m — alkylene with m=4 or 5 forming together with the central X-atom a five- or six-membered heterocycle wherein one or more H of —(CH 2 ) m — alkylene may be substituted by one or more substituents selected from F and optionally fluorinated C 1 -C 10 alkyl, and wherein one or more CH 2 groups of —(CH 2 ) m — alkylene may be replaced by O, S or NR′;

R′ is selected from C 1 -C 10 alkyl, C 2 -C 10 alkenyl, C 2 -C 10 alkynyl, C 6 -C 12 aryl, and C 7 -C 24 aralkyl, which may be substituted one or more groups selected from F, cyclopropyl, 1,2-epoxyethyl, and sulfonate, and wherein one or more CH 2 groups of alkyl, alkenyl, alkynyl and aralkyl which are not directly bound to the N-atom may be replaced by O, 1,2-epoxyethylene, cyclopropylene or SO 3 ;

n is an integer from 1 to 8 and wherein one or more CH 2 groups of the —(CH 2 ) n -alkylene chain which are not directly bound to the X-atom or the SO 3 group may be replaced by O and wherein two adjacent CH 2 groups of the —(CH 2 ) n — alkylene chain may be replaced by a C—C double bond or a C—C triple bond;

R 4 is selected from C 1 -C 6 alkyl, C 2 -C 20 alkenyl, C 2 -C 20 alkynyl, C 6 -C 12 aryl, and C 7 -C 24 aralkyl, which may be substituted one or more groups selected from F, cyclopropyl, 1,2-epoxyethyl, and sulfonate, and wherein one or more CH 2 groups of alkyl, alkenyl, alkynyl and aralkyl which are not directly bound to the SO 3 group may be replaced by O, 1,2-epoxyethylene, cyclopropylene or SO 3 ;

R 5 is selected from C 1 -C 20 alkyl, C 2 -C 20 alkenyl, C 2 -C 20 alkynyl, C 6 -C 12 aryl, and C 7 -C 24 aralkyl, wherein alkyl, alkenyl, alkynyl and aralkyl may be substituted by a group selected from cyclopropyl and 1,2-epoxyethyl, and wherein one or more CH 2 groups of alkyl, alkenyl, alkynyl and aralkyl which are not directly bound to the SO 3 group may be replaced by one or more groups selected from O, 1,2-epoxyethylene, cyclopropylene, SO 3 , and NR″; and

R″ is selected from C 1 -C 10 alkyl, C 2 -C 10 alkenyl, C 2 -C 10 alkynyl, C 6 -C 12 aryl, and C 7 -C 24 aralkyl, which be substituted by one or more groups selected from 1,2-epoxyethyl, cyclopropyl, and sulfonate, and wherein one or more CH 2 group of alkyl, alkenyl, alkynyl, and aralkyl, which are not directly bound to the N-atom may be replaced by O, 1,2-epoxyethylene, cyclopropylene or SO 3 .

2. The compounds compound according to claim 1 , wherein X is N.

3. The compound according to claim 1 , wherein —SO 3 — is —O—S(O) 2 —.

4. The compound according to claim 1 , wherein n is 1, 2, 3 or 4.

5. The compound according to claim 1 , wherein R 4 and R 5 are equal.

6. The compound according to claim 1 , wherein R 4 comprises at least one reactive group selected from the group consisting of C—C double bond, C—C triple bond, cyclopropyl, cyclopropylene, and epoxy.

7. The compound according to claim 1 , wherein R 5 comprises at least one reactive group selected from the group consisting of C—C double bond, C—C triple bond, cyclopropyl, cyclopropylene, and epoxy.

8. The compound according to claim 1 , wherein R 5 comprises at least one reactive group selected from the group consisting of C—C double bond, C—C triple bond, cyclopropyl, cyclopropylene, and epoxy.

9. The compound according to claim 1 , wherein —SO 3 — is —O—S(O) 2 and is obtained by reacting a compound of formula XR 1 R 2 R 3 with a compound of formula R 4 —S(O) 2 O—(CH 2 ) n —O—S(O) 2 R 5 .

10. An electrolyte composition containing comprising at least one compound of formula (I) according to claim 1 .

11. An electrolyte composition according to claim 10 , which further comprises at least one organic aprotic solvent selected from the group consisting of:

(a) cyclic and acyclic organic carbonates, which may be partly halogenated,

(b) di-C 1 -C 10 -alkylethers, which may be partly halogenated,

(c) di-C 1 -C 4 -alkyl-C 2 -C 6 -alkylene ethers and polyethers, which may be partly halogenated,

(d) cyclic ethers, which may be partly halogenated,

(e) cyclic and acyclic acetales and ketales, which may be partly halogenated,

(f) orthocarboxylic acids esters, which may be partly halogenated,

(g) cyclic and acyclic esters of carboxylic acids, which may be partly halogenated,

(h) cyclic and acyclic sulfones, which may be partly halogenated, and

(i) cyclic and acyclic nitrites and dinitriles, which may be partly halogenated.

12. An electrochemical or electrooptical device, comprising at least one compound of formula (I) according to claim 1 .

13. The electrochemical or electrooptical device according to claim 12 , wherein the electrochemical or electrooptical device is a lithium battery.

14. A method of making an electrolyte composition, the method comprising: adding at least one compound according to claim 1 to a composition that comprises a solvent and a conductive salt.

15. A method of forming a film on an anode, the method comprising: reducing at least one compound according to claim 1 on a surface of an anode, said anode being present in a lithium ion battery.