Electrochemical element with a very long calendar life

Abstract

The present invention relates to a positive electrode composition comprising a) as electrochemically active materials: i) a lithium manganese iron phosphate compound of formula LixMn1-y-zFeyMzPO4 (LMFP) where 0.8≤x≤1.2; 0.5≤1-y-z≤1; 0≤y≤0.5; 0≤z≤0.2 and where M is selected from the group consisting of B, Mg, Al, Si, Ca, Ti, V, Cr, Co, Ni, Cu, Zn, Y, Zr, Nb, S, W, K, Pb, V, Mo, Hf, Bi, Se and mixtures thereof; and ii) a lithium nickel manganese cobalt (NMC) oxide compound of formula Liw(NixMnyCOzMt)O2 where 0.9≤w≤1.1; 0<x≤1.1; 0<y≤1.1; 0<z≤1.1; 0<t≤1.1, and where M is selected from the group consisting of Al, B, Mg, Si, Ca, Ti, V, Cr, Fe, Cu, Zn, Y, Zr, Nb, W, Mo, S, Sr, Ce, Ta, Ga, Nd, Pr, La and mixtures thereof; and b) as electronic conductor: more than 0.01 wt.% of single-walled carbon nanotubes (SWCNT) relative to the total weight of the composition, preferably more than 0.05 wt%, and more preferably more than 0.1 wt% relative to the total weight of the composition. The invention further relates to a positive electrode, an electrochemical element and a battery comprising said composition. Finally, the invention relates to the use of an electrochemical element comprising a composition as described above for improving the calendar life of the electrochemical element.

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