Manganese phosphate coated Li[Ni0.6Co0.2Mn0.2]O2 cathode material: Towards superior cycling stability at elevated temperature and high voltage

Surface/Interface Structure Degradation of Ni‐Rich Layered Oxide Cathodes toward Lithium‐Ion Batteries: Fundamental Mechanisms and Remedying Strategies

“…Now that the parasitic side reactions start from the interfaces between the solid cathodes and liquid electrolytes, the most effective method is to avoid their direct contact by introducing passive physical protection layer on the cathode surface . In general, the employed coating species can be categorized into i) the chemically and electrochemically inactive coatings, including metal oxides (Al 2 O 3 , TiO 2 , MgO, SiO 2 , ZrO 2 , V 2 O 5 , Nb 2 O 5 , ZnO, MoO 3 , and Y 2 O 3 ,) and phosphates (AlPO 4 , MnPO 4 , Mn 3 (PO 4 ) 2 , La(PO 4 ) 3 , Ni 3 (PO 4 ) 2 , Co 3 (PO 4 ) 2 , ZrP 2 O 7 , and FePO 4 ) as well as some fluorides (AlF 3 and LiF); ii) the Li + conductive coatings, mainly refer to the Li‐containing compounds such as LiAlO 2 , Li 2 ZrO 3 , Li 3 VO 4 , Li 2 MnO 3 , LiMn 2 O 4 , Li 3 PO 4 (LPO), LiFePO 4 (LFP), LiMnPO 4 , Li 2 TiO 3 , LiTiO 2 , Li 2 O‐2B 2 O 3 , LiTi 2 (PO 4 ) 3 , LiZr 2 (PO 4 ) 3 , Li 1.4 Al 0.4 Ti 1.6 (PO 4 ) 3 , Li 0.5 La 0.5 TiO 3 , LiTaO 3 , Li 4 SiO 4 , and LiAlF 4 as well as some heterostructured electrochemical active cathodes (Li 1.2 Ni 0.2 Mn 0.6 O 2 , Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O 2 and NCM333); and iii) the electron conducting coating, representatively, reduced graphene oxide (rGO), permeable poly (3,4‐ethylenedioxythiophene) (PEDOT),…”

“…Innovatively, a precise, uniform, and ultrathin AlPO 4 coating layer is achieved on the NCM333 surface via introducing a novel organic ligand coordination complex, rendering a significant enhancement in electrochemical properties . Additionally, Chen et al first investigate the positive influence of the MnPO 4 coating on the LiNi 0.4 Co 0.2 Mn 0.4 O 2 (NCM424) cathode . Both findings demonstrate that a uniform MnPO 4 nanocoating (Figure b) on the Ni‐rich cathodes surface can endow substantial superiorities involving rapid Li + ions diffusion and remarkably improved cycling stability at high operated temperatures, elevated cutoff voltages and mass loadings (Figure c) …”

Hierarchical porous LiNi1/3Co1/3Mn1/3O2 with yolk–shell-like architecture as stable cathode material for lithium-ion batteries

“…These are primarily attributed to (1) more severe Li + /Ni 2+ cation mixing that can trigger phase transitions; (2) the formation of surface lithium-containing residuals (e.g., LiOH, Li 2 CO 3 ) that can not only build accumulative resistance hindering the charge transfer at the interface of electrode/electrolyte but also generate gas (O 2 , CO, CO 2 ) during cycling; (3) the formation of oxygen species due to the reactions of highly reactive Ni 4+ at delithiation status with electrolyte, concomitantly with structural evolutions. [17][18][19] By far, LiNi 1/3 Co 1/3 Mn 1/3 O 2 which shows advantages of better structural and thermal stability and more stable cycling stability over those Ni-rich NCM cathode materials, has been deemed as the most ideal cathode material because of its overall modest performance. 20 However, drawbacks including the fatal capacity degradation in terms of long cycles and inferior rate capability especially at high C-rates as a result of sluggish lithium ions diffusion ($10 À11 cm 2 s À1 ) 21,22 have impeded its wide spread usage in high-power applicants.…”

Ni‐Rich/Co‐Poor Layered Cathode for Automotive Li‐Ion Batteries: Promises and Challenges

“…So the generated heat of pristine NCM‐622 was also decreased after coated by Mn 3 (PO 4 ) 2 from 1882 to 1170 J g −1 . After that, Chen et al104 reported the thermal stability of MnPO 4 ‐coated NCM‐622. The onset decomposition temperature of NCM‐622 shifts to higher temperature from 274 to 285.6 °C after coated MnPO 4 .…”