Voltage prediction from Coulomb potential created by atoms of spinel LiMn2O4 cathode active material for Li ion cells

We studied the contribution of internal energy and entropy change to cathod e voltage assuming that the cathode material LixMn2O4 was completely ionic and only the Coulomb potential was effective. We calculated the cathode vol tage of an ideal spinel structure LixMn2O4 (Fd3m) (Mn-O: 2 Angstrom, Li-O: 1.732 Angstrom, O-O: 2.828 Angstrom). From this calculation, we found that LixMn2O4 has a multiphase co-existence for 0 < x < 1 with a very high volta ge (8.7 V versus Li), and has a negative voltage when 1 < x. If we suppose that inserted Lif and electron have 40% of the formal charge, LixMn2O4 has a voltage from 4.55 to 4.79 V for 0 < x < 1, and has a voltage of 1.75 V wh en 1 < x. (C) 2001 Elsevier Science B.V. All rights reserved.