Insight of a Phase Compatible Surface Coating for Long‐Durable Li‐Rich Layered Oxide Cathode

• Published in: Advanced energy materials Vol. 9; no. 34
• Main Authors: Hu, Sijiang, Li, Yu, Chen, Yuhua, Peng, Jiming, Zhou, Tengfei, Pang, Wei Kong, Didier, Christophe, Peterson, Vanessa K., Wang, Hongqiang, Li, Qingyu, Guo, Zaiping
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 01.09.2019
• Subjects: Cathodes; Degradation; Electrical resistivity; Electrode materials; Electrodes; Interfacial bonding; Ion currents; Lithium manganese oxides; Lithium-ion batteries; Li‐rich layered oxide; metal ion migration; Protective coatings; Surface layers; surface‐coating; voltage fade
• ISSN: 1614-6832; 1614-6840
• DOI: 10.1002/aenm.201901795

Li‐rich layered oxides (LLOs) can deliver almost double the capacity of conventional electrode materials such as LiCoO2 and LiMn2O4; however, voltage fade and capacity degradation are major obstacles to the practical implementation of LLOs in high‐energy lithium‐ion batteries. Herein, hexagonal La0.8Sr0.2MnO3−y (LSM) is used as a protective and phase‐compatible surface layer to stabilize the Li‐rich layered Li1.2Ni0.13Co0.13Mn0.54O2 (LM) cathode material. The LSM is MnOM bonded at the LSM/LM interface and functions by preventing the migration of metal ions in the LM associated with capacity degradation as well as enhancing the electrical transfer and ionic conductivity at the interface. The LSM‐coated LM delivers an enhanced reversible capacity of 202 mAh g−1 at 1 C (260 mA g−1) with excellent cycling stability and rate capability (94% capacity retention after 200 cycles and 144 mAh g−1 at 5 C). This work demonstrates that interfacial bonding between coating and bulk material is a successful strategy for the modification of LLO electrodes for the next‐generation of high‐energy Li‐ion batteries. A facile surface engineering strategy is used to introduce a phase‐compatible La0.8Sr0.2MnO3−y (LSM) coating with an R3¯c hexagonal symmetry to a Li1.2Ni0.13Co0.13Mn0.54O2 (LM) cathode material with hexagonal R3¯m symmetry. The electrode bulk structure is stabilized by the coating by the heterostructural MnOM (Ni, Co, or Mn) bonding at the LSM/LM interface.