| abstract |
The invention provides an electrochemical cell which includes a first electrode and a second electrode which is a counter electrode to said first electrode, and an electrolyte material interposed there between. The first electrode comprises an electrode active material represented by the general nominal formula Aa[Mm,Mln,MIIo](XY4)dZe, wherein at least one of M, MI and MII is a redox active element, 0 < m,n,o 5 4, and 1/2[V(MI) + V(MII)] = V(M), wherein V(M) is the valence state of M, V(MI) is the valence state of Ml, and V(MII) is the valence state of MII. |