Mn4+ environment in layered Li[Mg0.5−xNixMn0.5]O2 oxides monitored by EPR spectroscopy

Mn-containing catalytic materials for the total combustion of toluene: The role of Mn localisation in the structure of LDH precursor

“…4 shows the ESR spectra of MgMnAlNO 3 (600) and MgAlMnO 4 (600) recorded at room temperature. Both are dominated by a broad (DB = 340 mT) signal with g = 1.94, characteristic of closely interacting Mn 4+ (as in MnO 2 ) [42,43]. Additionally, in the spectrum of MgAlMnO 4 (600), a component with g = 2.01 and DB = 48 mT can be seen, pointing to the existence of Mn 2+ centres.…”

Effect of the synthesis procedure on the local cationic distribution in layered LiNi1/2Mn1/2O2

“…In addition, there is a strong tendency for local Li + and Mn 4+ ordering in the transition metal layers [18][19][20][21]9]. 6 MAS-NMR analysis clearly shows that Li + ions in the transition metal layers are preferentially surrounded by Mn 4+ [18].…”

“…However, the electronic structure of both compositions is different. With LiNi 1/2 Mn 1/2 O 2 , nickel and manganese ions adopt the oxidation state of (+2) and (+4), respectively [5][6][7][8][9], while only Co 3+ ions are stabilized in LiCoO 2 [2,3]. * Corresponding author.…”

“…(where x =2/7 and ı 1 = 0.06 were calculated), while the rest of Mn 4+ are in the Ni,Mn-environment corresponding to the Li 1-ı2 Ni ı2 [Ni 1−y Mn y ]O 2 (y < 1/2) composition with a statistical Ni,Mn distribution [9,22,23]. Based on computational and experimental approach, Ceder and coworkers have demonstrated that the cationic order in both lithium and transition metal layers is temperature-driven: at a temperature higher than 620 • C, there is a transition from "flower"-type cationic order to energetically favorable cationic distribution of a √ 3a × √ 3a type (denoted also as honeycomb-type model) [17].…”

Effect of carbon coating process on the structure and electrochemical performance of LiNi0.5Mn0.5O2 used as cathode in Li-ion batteries

“…Nowadays, with the development of high-power consuming electric devices, a lot of efforts have been paid on the modification of LiNi 0.5 Mn 0.5 O 2 so as to further improve its performance during cycling at high rate, such as coating [11] and doping with other guest ions [3,[12][13][14][15][16][17][18][19]. Surface modification by carbon is one of feasible methods due to the following reasons.…”