Electrode materials with high surface conductivity
View Patent ↗The present invention concerns electrode materials capable of redox reactions by electrons and alkali ions exchange with an electrolyte. The applications are in the field of primary (batteries) or secondary electrochemical generators, super capacitors and light modulating system of the super capacitor type.
1. An electrode material comprising a complex oxide having a spinel structure and corresponding to the general formula AaMmOoNnFf wherein
the coefficients a>0, m≧0, o>0, n≧0, and f≧0, said coefficients being selected to ensure electroneutrality;
A comprises an alkali metal;
M comprises solely or mainly Ti, and optionally at least one a non-transition metal;
O is oxygen;
N is nitrogen;
F is fluorine; and
wherein said oxide comprises a non powdery deposit of a conductive carbonaceous material on a surface thereof; said deposit being obtained by contacting the said complex oxide with a carbon precursor and pyrolysis of said precursor; and
wherein the carbonaceous material has a structural integrity upon electrochemical reaction of the electrode material.
2. An electrode material of claim 1 , wherein the complex oxide has the formula Li 4+x Ti 5 O 12 or Li 4+x−2y Mg y Ti 5 O 12 , wherein 0≦x and y≦1.
3. An electrode material of claim 1 , wherein the non transition metal comprises magnesium or aluminum.
4. An electrode material of any one of claims 1 to 3 , wherein the carbonaceous material is a solid polymer having a carbon content of from 60 to 100%, the other elements being H, O or N, and the said electrode material has a conductivity higher than 10 −5 S/cm at room temperature.
5. An electrode material of any one of claims 1 to 3 , wherein the concentration of carbonaceous material is between 0.2 and 15% (w/w).