Li[Li[sub y]Mn[sub 2−y]]O[sub 4] Spinel Cathode Material Prepared by a Solution Method

Li [ Li x Mn 2 − y ] O 4 ( y = 0.03 , 0.07 , 0.14 ) spinel powders were prepared from aqueous solutions of LiOH · H 2 O and Mn ( CH 3 COO ) 2 · 4 H 2 O , which is a simpler and cheaper method than any other solution‐based synthesis. The spinels thus prepared exhibited excellent capacity retention in the voltage range of 2.4 – 3.4 V in spite of the cooperative Jahn‐Teller distortion. The cyclability in the 4 V range ( 3.3 – 4.3 V ) was improved as the lithium content on the octahedral site increased while the reversible capacity was sacrificed. Cycling over the whole 2.4 – 4.3 V range indicates that charging in the 4 V range introduces an irreversible change that causes capacity fading in the 3 V range, but not in the 4 V range.