Surface topological synthesis of polymetallic oxides coatings on lithium layered oxide for improved capacity and...

Surface coating of lithium layered oxide cathode (e.g., LiNi_0.5Co_0.3Mn_0.2O₂, NCM532) has become an important modified method in lithium-ion batteries for pursuing higher capacity and rate performance and safety. However, the design and synthesis of polymetallic oxide (PMO) coatings on lithium layered oxide is still a challenge. Herein, polymetallic alloys (PMA) such as NiCoMn alloys (NCM), LaZrHfMo alloys (LZHM) and LaZrHfZn alloys (LZHZ) are introduced to synthesize PMO coatings on NCM532 by a surface topological conversion strategy. The advantage of this method is that numerous kinds of elements could be converted into PMO coating layer with high reaction efficiency, element universality and uniform arrangement at atomic scale. The PMO coatings modified cathodes show excellent rate performance. All of these are attributed to the fact that the PMO coating layers can effectively reduce the side reaction with electrolyte, increase the conductivity of Li⁺ and effectively reduce the mixing of Li⁺/Ni²⁺, maintain the stability of structure, and greatly increase the reversible capacity of NCM532. Our PMO coating strategy is also applicable to other cathode materials, such as Ni-rich and Li-rich cathode materials.