Lithium storage cell presenting both a high electrical potential and a high lithium insertion capacity

Lithium storage cell comprising at least a first electrode comprising an active material wherein Li+ cations can be inserted, a second electrode and an electrolyte, wherein the active material comprises a linear condensed compound comprising at least two tetrahedra, respectively of AO4 and A′O4 type, bonded by a common oxygen atom and wherein an M2+ ion of transition metal with a degree of oxidation of +2 is inserted, the ratio between the number of Li+ cations able to be inserted in the active material and the number of transition metal ions M2+ being strictly greater than 1, A and A′ being selected from the group consisting of P5+, Si4+, Al3+, S6+, Ge4+, B3+ and M2+ being selected from the group consisting of Ni2+, Co2+, Mn2+, Fe2+ and Ti2+, wherein

• the active material has the following general formula (I):
• LiaXbMZd(A2O7)e(A′O3)f (I)
• in which:
• X represents at least one alkaline metal with a degree of oxidation of +1 selected from the group consisting of Li+, Na+, K+,
• M represents at least one transition metal with a degree of oxidation of +2 selected from the group consisting of Ni2+, Co2+, Mn2+, Fe2+, Ti2+,
• Z represents at least one element selected from the group consisting of the metal ions Cu+, Ag+, Mg2+, Ca2+, Sr2+, Zn2+, V2+, Cu2+, Al3+, Ti3+, Cr3+, Fe3+, Mn3+, Ga3+, V3+, Ge4+, Sn4+, Mo4+, Ti4+, V4+, V5+, Ta5+, Nb5+ and Mo6+, the chemical elements O, S, F and Cl and a group of A″O4 type,
• A″ is a cation selected from the group consisting of P5+, Si4+, Al3+, S6+, Ge4+, B3+,
• a>1,
• b and d≧0
• and e and f>0.