The Spinel Phase of LiMn2 O 4 as a Cathode in Secondary Lithium Cells

Abstract

The electrochemical properties of LiMn2O4 and LiMyMn2−yO4 false(M=normalTi,normalGe,normalFe,normalZn,normalor Nifalse) were studied for different conditions of sample preparation and different degrees of cation substitution false(yfalse) . In the voltage range 3.5–4.5 V, cells of either spinel LiMn2O4 or λ‐MnO2 (made by leaching the Li from LiMn2O4 ) reversibly insert 0.4 Li per Mn at an average voltage of 4.1 V, leading to an energy density of 480 Wh/kg of cathode. Cells cycled 50 times lost less than 10% of their initial capacity, suggesting that this material could be used instead of LiCoO2 or LiNiO2 as the cathode in the new generation of “rocking chair batteries.” Replacing Mn with cations of valence 2 (Ni, Zn) or 3 (Fe) reduces the amount of Mn+3 and correspondingly reduces the capacity of the cells at 4.1 V, but does not affect their cycling performance.

Microemulsion‐Assisted Synthesis of Nanosized LiMnO Spinel Cathodes for High‐Rate Lithium‐Ion Batteries

“…[35] However, the material suffers from a drastic capacity loss because of the difficulty in the reversible phase transition between the cubic LiMn 2 O 4 and the tetragonal Li 2 Mn 2 O 4 structure. Thus, we also evaluated the cycling responses of nano-sized Li 1 C, respectively. With the increased current density, the plateaus in the voltage profile move downward (inset in Figure 4 d) owing to increased overpotentials of the electrode and the internal IR drop.…”

“…[1][2][3][4][5][6][7] However, this material suffers from the drawback of slow dissolution of Mn 2 + into the electrolyte according to the disproportionation reaction: 2 Mn 3 + !Mn 2 + + Mn 4 + , and thus results in a limited cycling stability. To overcome this issue, recent interests have been focused on making samples with lithium-rich compositions (e.g.…”

Crystallography and Growth of Epitaxial Oxide Films for Fundamental Studies of Cathode Materials Used in Advanced Li-Ion Batteries

“…The true spinel structure is realized in LiMn 2 O 4 [40][41][42][43][44][45], with Li occupying tetrahedral sites, as shown in Figure 1d. This phase was studied as a possible substitution for LiCoO 2 , for two main reasons: (a) three-dimensional diffusion of Li in the cubic structure is facilitated, enabling an anticipated high-rate performance, and (b) potential replacement of Co by the less expensive and environment-friendly Mn.…”

Electrochemical Characterization of Al3+Doped Spinel Cathode Active Nanoparticles for Li-Ion Batteries

“…LiMn 2 O 4 spinel was traditionally prepared by solidstate reaction directly at high temperatures [8,9]. In recent years, nanostructures have received intensive attention because of both their fundamental importance and the wide range of their potential applications in many areas.…”