Formation and Structural Properties of Layered LiMnO[sub 2] Cathode Materials

Abstract

LiAl x Mn 1Ϫx O 2 and LiCr x Mn 1Ϫx O 2 compounds (x Յ 0.10) with an ␣-NaFeO 2 layer-type crystal structure have been prepared by a high temperature solid-state route. The compounds are well ordered with Al or Cr sharing the Mn sites and no detectable cation mixing between Mn and Li layers. Both Al-and Cr-substituted materials cycled between 4.4 and 2.0 V in Li cells at 55ЊC show high stability of capacity. However the Al-substituted materials undergo a structural transformation to a spinel-type phase, accompanied by evolution of the discharge voltage curve to a two-plateau profile. Materials modified with small amounts of Cr show a different evolution of the discharge voltage. X-ray diffraction data for cycled LiCr x Mn 1Ϫx O 2 cathodes show that these compounds do not undergo significant transformation to spinel on cycling, but retain a hexagonal structure established on first charge.

Hydrothermal synthesis of orthorhombic LiMnO2 nano-particles and LiMnO2 nanorods and comparison of their electrochemical performances

“…This structural analogy motivated us to prepare and study its performance as a cathode material. The theoretical discharge capacity of layered LiMnO 2 is 285 mA·h/g [11], which is much higher than LiMn 2 O 4 and LiCoO 2 . As a result, layered LiMnO 2 is of high fundamental and technological interest as a cathode material for rechargeable lithium batteries.…”

Chemical synthesis and characterization of Mn3O4 thin films for supercapacitor application

“…There are four crystalline phases of manganese oxides (MnO, Mn 2 O 3 , MnO 2 , and Mn 3 O 4 ) which have different structural and compositional properties and serve in various applications. Manganese dioxide (MnO 2 ) can be used as a catalyst in oxidation-reduction reactions, as electrode materials in batteries, and in energy storage devices such as ultracapacitors [5]. The dimanganese trioxide phase (Mn 2 O 3 ) is quite attractive owing to its applications to produce soft magnetic materials [6] to catalyze the removal carbon monoxide and nitrogen oxide from waste gas [7,8] and in the catalytic combustion of methane [9].…”

Structural and electrochemical study of Li[CrxLi(1−x)/3Mn2(1−x)/3]O2 (0≤x≤0.328) cathode materials

“…Hence, Li 2 CrO 4 is easily generated in an air atmosphere. However, the generation of Li 2 CrO 4 has not previously been reported in an inert atmosphere, due to the insufficiency of the oxygen supply [6,[16][17]. The decrease in the chromium content indicated by the inductively coupled plasma results was confirmed by the X-ray diffraction study which shows the This observation suggests that obtaining the target stoichiometry is difficult in an air atmosphere, due to the generation of Li 2 CrO 4 , and it is difficult to accurately determine the amount of chromium removed.…”

“…Besides, layered LiMnO 2 transforms into a spinel structure during the lithium insertion/extraction process, due to cation migration [3]. In order to obtain compounds with prolonged structural integrities, derivative layered manganese oxides [4][5][6][7][8] and lithium-saturated solid solutions or nanocomposite Li 2 MnO 3 -LiMO 2 [9][10][11][12][13] have been investigated which also exhibit enhanced electrochemical performances. Li 1.2 Cr 0.4 Mn 0.4 O 2 shows relatively high capacity and cycling stability [14].…”