Non-aqueous electrolyte for a high-voltage lithium battery
The invention relates to a positive electrode/electrolyte pair for lithium batteries operating at a voltage above 4.2 V versus Li+/Li. The electrolyte of the lithium battery used in the invention includes at least a first additive chosen from optionally substituted, cyclic or acyclic, carboxylic or dicarboxylic anhydrides and carboxylic or dicarboxylic acids, and mixtures thereof, and optionally a second additive which is a lithium salt, the total content of additive(s) being greater than or equal to 0.01% by weight and less than or equal to 30% by weight, relative to the total weight of electrolyte, and the positive electrode is made of a material having a spinel structure. The lithium batteries of the invention are applicable in particular in the field of portable equipment, such as telephones, computers, camcorders, cameras and tooling.
1. A positive electrode/electrolyte pair for a lithium battery, characterized in that:
the positive electrode is made of a material with a spinel structure of the following formula (I) and has a lattice parameter of between 8.167 and 8.190 Å:
Li y Ni 0.5−x Mn 1.5+x O 4−δ Formula (I)
in which:
0.9<y≦1.1;
0≦x≦0.1; and
δ≧0,
and in that:
the electrolyte is a solution of a lithium salt containing at least one first additive chosen from butane-1,4-dicarboxylic anhydride and 2-methylene butane1,4dicarboxylic anhydride, and mixtures thereof, and optionally a second additive that is a lithium salt.
2. The pair as claimed in claim 1 , characterized in that the total amount of electrolyte additive(s) is greater than or equal to 0.01% by weight and less than or equal to 30% by weight relative to the total weight of electrolyte.
3. The pair as claimed in claim 1 , characterized in that the total amount of additive(s) of the electrolyte is greater than 1% by weight and less than or equal to 15% by weight relative to the total weight of electrolyte.
4. The pair as claimed in claim 1 , characterized in that the total amount of additive(s) of the electrolyte is greater than 5% by weight and less than or equal to 10% by weight relative to the total weight of electrolyte.
5. The pair as claimed in claim 1 , characterized in that the total amount of additive(s) of the electrolyte is 10% by weight relative to the total weight of electrolyte.
6. The pair as claimed in claim 1 , characterized in that the second electrolyte additive, when present, is preferably lithium bis(oxalato)borate (LiBOB) of formula LiBC 4 O 8 .
7. The pair as claimed in claim 1 , characterized in that the positive electrode is made of a material with a spinel structure of formula (I) as defined in claim 1 and has a lattice parameter of between 8.179 and 8.183 Å.
8. The pair as claimed in claim 1 , characterized in that the positive electrode is made of a material with a spinel structure of formula LiNi 0.4 Mn 1.6 O 4 .
9. A lithium battery characterized in that it comprises a positive electrode/electrolyte pair as claimed in claim 1 .