NOVELTY - A battery (10) comprises a spirally coiled electrode assembly (12) and an electrolyte enclosed in a cylindrical casing (14). The spirally coiled electrode assembly comprises: a positive electrode (16) comprising polyanion based compound (I); a negative electrode (18) comprising intercalation active material; electrolyte in ion-transfer communication with positive and negative electrode; and separator (20) interposed between negative and positive electrode. The electrolyte comprises solvent containing mixture of cyclic carbonate and non-cyclic carbonate.    USE - As battery (claimed).    ADVANTAGE - The electrochemical cells afford benefits over known electrochemical cells, such benefits include increased capacity, enhanced cycling capability, enhanced reversibility, enhanced ionic conductivity, enhanced electrical conductivity, and reduced costs.    DETAILED DESCRIPTION - A battery (10), comprises: a spirally coiled electrode assembly (12) and an electrolyte enclosed in a cylindrical casing (14). The spirally coiled electrode assembly comprises: a positive electrode (16) comprising polyanion based compound of formula: AaMm(XY4)3Ze (I); a negative electrode (18) comprising an intercalation active material; an electrolyte in ion-transfer communication with the positive electrode and the negative electrode; and a separator (20) interposed between the negative electrode and the positive electrode. The electrolyte comprises a solvent comprising a mixture of a cyclic carbonate and a non-cyclic carbonate. The A, M, X, Y', Z, a, m, x, y, z, and e are selected so as to maintain electroneutrality of the compound.    A=elements from Group 1 of the Periodic Table or their mixtures;    a=0-9;    M=at least one redox active element;    m=1-3;    XY4=X'(O4-x, Y'x), X'(O4-y, Y'2y), X1S4 or ((X'1)z, X'(1-z))O4;    X' and X'1=P, As, Sb, Si, Ge, V or S;    X1=P, As, Sb, Si, Ge or V;    Y'=halo, S or N;    x=0.1-3;    y=0.1-2;    z=0.1-1;    Z=hydroxyl (OH) or halogen selected from Group 17 of the Periodic Table;    e=0.1-4.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic cross-sectional diagram of a non-aqueous electrolyte cylindrical electrochemical cell.    Battery (10)    Spirally coiled electrode assembly (12)    Cylindrical casing (14)    Positive electrode (16)    Negative electrode (18)    Separator (20)