Lattice‐Matched Interfacial Modulation Based on Olivine Enamel‐Like Front‐Face Fabrication for High‐Voltage LiCoO₂

Abstract

The high‐voltage induced undesirable surface passivation bilayer (cathode/electrolyte interface and cation‐densified surface phase) of LiCoO2 inevitably leads to battery degradation. Herein, a continual/uniform enamel‐like olivine layer on LiCoO2 surface is fabricated by employing a high‐speed mechanical fusion method . The enamel‐like layer suppresses interfacial side reactions by tuning EC dehydrogenation, contributing to an ultrathin and stable cathode/electrolyte interface. The strong bonding affinity between LiCoO2 and enamel‐like layer restrains both lattice oxygen loss and associated layered‐to‐spinel structural distortion. Moreover, the thermal stability of highly delithiated LiCoO2 is improved, as both the onset temperatures of layered‐to‐spinel transition and O2 evolution are simultaneously postponed. Stable operation of LiCoO2 at 4.6 V high‐voltage and 55 °C elevated temperature (both >85% capacity retention after 200 cycles) is achieved. This facile and scalable high‐speed solid‐phase coating strategy establishes a technical paradigm to enhance surface/interface stability of high‐energy‐density cathode candidates by constructing an ideal enamel‐like surface layer.

Enhancing the Structural Stability of LiCoO2 at Elevated Voltage via High-Valence Sb Doping

“…In Figure f, after 50 cycles, PLCO showed a new peak at the (003) position, indicating the occurrence of a spinel phase transition. This suggests that, due to structural alterations, a fraction of the layered structure transformed into a spinel structure during the cycling process . In contrast, Sb–LCO did not show a new peak, confirming that there were no phase transitions after cycling and enhancing the stability of the doped structure.…”

Ether-Based High-Voltage Lithium Metal Batteries: The Road to Commercialization

“…Theoretical calculations, such as molecular dynamics simulations and density functional theory, − can be applied to investigate the oxidative stability of various components of electrolytes in thermodynamics, along with the influence of electrolyte components on solvation structures of electrolytes. Meanwhile, various advanced characterization techniques developed in recent years, such as cryo-electron microscopy, , electrochemical quartz crystal microbalance, , the time-of-flight secondary ion mass spectroscopy (ToF-SIMS), , X-ray photoelectron spectroscopy (XPS), , etc., should be applied to conduct an accuracy analysis of the structures of CEI and SEI. This enables the establishment of a relationship between the composition of CEI and SEI and their stability.…”

Construction of Uniform LiF Coating Layers for Stable High-Voltage LiCoO2 Cathodes in Lithium-Ion Batteries

“…The internal stress changes caused hinder the lithium-ion transport in the materials, showing poor cycling performances and rate capabilities [17][18][19][20]. Furthermore, the higher delithiated LiCoO 2 (more than 0.5 Li removed at a cut-off voltage above 4.2 V) is highly oxidized, which could increase the likelihood of side reactions between the electrode materials and the electrolyte [21][22][23]. The resulting Co metal dissolution, electrolyte decomposition and surface phase degradation lead to poor cycling stability and safety problems [24][25][26].…”