Patent ID: 8236450

Claim:
A lithium insertion-type positive electrode material based on the orthosilicate structure comprising a compound according to Formula I: Li x+y M 1−(y+d+t+q+r) D d T t Q q R r [SiO 4 ] 1−(p+s+v+a+b) [SO 4 ] s [PO 4 ] p [VO 4 ] v [AlO 4 ] a [BO 4 ] b (I) wherein M is selected from the group consisting of Mn 2+ and Fe 2+ and mixtures thereof; D is a metal in the +2 oxidation state selected from the group consisting of Mg 2+ , Ni 2+ , Co 2+ , Zn 2+ , Cu 2+ , Ti 2+ and Ca 2+ ; T is a metal in the +3 oxidation state selected from the group consisting of Al 3+ , Ti 3+ , Cr 3+ , Fe 3+ , Mn 3+ , Ga 3+ , Zn 2+ and V 3+ ; Q is a metal in the +4 oxidation state selected from the group consisting of Ti 4+ , Ge 4+ , Sn 4+ and V 4+ ; R is a metal in the +5 oxidation state selected from the group consisting of V 5+ , Nb 5+ and Ta 5+ ; and M, D, T, Q, R are elements residing in the tetrahedral sites of the Fe ions in Li 2 FeSiO 4 ; and wherein x, y, d, t, q, r, p, s, v, a, b are between 0 and one; or wherein x is between 0 and 2, y+d+t+q+r are less than 1, p+s+v+a+b are less than 1 and 3+2y+a+b=y+t+2q+3r+2s+p+v.