Revisiting Delithiated Li_1.2Mn_0.54Ni_0.13Co_0.13O₂: Structural Analysis and Cathode Properties in Magnesium Rechargeable Battery Applications

Abstract

Chemically-delithiated Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O 2 is regarded as a potential candidate of cathode active materials for magnesium rechargeable batteries owing to its large deliverable capacity and high operation voltage compared to conventional layered transition metal oxides. Our previous study suggested its chemical composition as Li 0.13 Mn 0.54 Ni 0.13 Co 0.13 O 2−δ by X-ray diffraction combined with XAFS analysis. We herein re-analyzed the substantial composition and crystal structure by employing titration technique and combination of neutron and synchrotron X-ray diffractions. Two topotactic phases both belonging to the space group of R 3m were strongly suggested by Rietveld analysis, and the chemical formula was subsequently re-defined as Li 0.17 Mn 0.72 Ni 0.18 Co 0.18 O 2 where oxygen defects were filled by a rearrangement from C2/m structure. Although the battery performance of that active material was poor in the previous study, the discharge capacity greater than 400 mAh g −1 , ca. 95 % of the theoretical capacity, was achieved by using certain anodically stable electrolytes and specific cell configuration. This result strongly implies that the R 3m structure is particularly suitable as a host material for Mg 2+ intercalation.

A Review of Chemically Induced Intercalation and Deintercalation in Battery Materials

“…Ishida et al used the chemical delithiation method to exploit delithiated lithium‐rich Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O 2 as a Mg 2+ intercalation material in magnesium rechargeable battery applications. [ 92 ] Delithiation of LiFePO 4 with Br 2 and NO 2 BF 4 has been performed for the use of heterosite FePO 4 as sodium intercalation material. [ 93,94 ] Subsequent sodiation can be performed in a Na–metal/FePO 4 cell, or by chemical sodiation with NaI.…”

Investigation of Stable Structures and Electronic States of Spinel-Structured MgCo2–zNi0.5MnAlzO4 (Z = 0, 0.3) as Cathode Materials for Magnesium Rechargeable Batteries Using First-Principles Calculations

“…The combination of a highly efficient and electrochemically stable electrolyte and ZnMnO 3 nanoparticles with shortened diffusion pathways has been reported to result in stable battery cycling even at 30 °C . In addition to the spinel-type cathode materials, various other cathode materials have been developed, including stoichiometric MgFePO 4 F, vanadium phosphate V 2 (PO 4 ) 3 , rocksalt-structured Mg x Ni y Co z O 2 ( x + y + z ≤ 2.0), a Li + -ion cathode material chemically desorbed from Li, and ion-exchanged MgFeSiO 4 . Furthermore, numerous studies of rechargeable battery materials have been conducted using first-principles calculations and molecular dynamics simulations. − Ceder et al showed that the performance of Li-rich cationic anisotropic rocksalt cathodes is improved by Mg-substitution …”

Metastable and Nanosized Li_1.2Nb_0.2V_0.6O₂ for High-Energy Li-ion Batteries

“…[2][3][4][5][6] However, the researches on the Li2MnO3-based systems have revealed that anionic redox triggers partial oxygen loss and subsequent irreversible phase transition, resulting in voltage decay on continuous cycles and restricting its use for practical battery applications. 7,8 Recently, our group has reported that the x Li3NbO4 − (1−x) LiVO2 binary system can be used for high-capacity positive electrode materials without anionic redox involvement. 9,10 Unlike Li2MnO3-based systems, better capacity retention is achieved in Li-excess vanadium-based oxides, Li1.25Nb0.25V0.5O2 (x = 0.33 in x Li3NbO4 − (1−x) LiVO2), with two-electron cationic redox of V 3+ /V 5+ .…”