Motivated by the increasing cost, environmental concerns, and limited availability of Co, researchers are actively seeking alternative cathode materials for lithium‐ion batteries. A promising strategy involves structure‐modified materials, such as a NiMn core/shell system. This design leverages the high energy density of a Ni‐rich core while employing an Mn‐rich shell to enhance interfacial stability by suppressing unwanted reactions with the electrolyte. This approach offers improved cycling stability and reduced reliance on Co. However, the interdiffusion of Mn ions between the core and shell remains a significant challenge during synthesis. This work presents a facile approach to address the issue of Mn interdiffusion in core/shell cathode materials. The study demonstrates that partial oxidation of the precursor during the drying stage effectively enhances the Mn oxidation state. This strategy successfully suppresses Mn interdiffusion during subsequent calcination, leading to the preservation of the core/shell architecture in the final cathode material. This optimized structure mitigates interfacial reactions, enhances chemomechanical properties, and reduces crosstalk, a major contributor to rollover failure. This work presents a novel approach for synthesizing high‐performance core/shell cathode materials for next‐generation lithium‐ion batteries.

中文翻译：

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通过氧化态控制对Mn进行表面钉扎合成无钴、富镍、核/壳结构正极材料


受成本增加、环境问题和钴供应有限的推动，研究人员正在积极寻找锂离子电池的替代阴极材料。一种有前途的策略涉及结构改性材料，例如 NiMn 核/壳系统。该设计利用富镍核的高能量密度，同时采用富锰壳，通过抑制与电解质的不需要的反应来增强界面稳定性。这种方法提高了循环稳定性并减少了对 Co 的依赖。然而，核和壳之间 Mn 离子的相互扩散仍然是合成过程中的一个重大挑战。这项工作提出了一种解决核/壳正极材料中锰相互扩散问题的简便方法。研究表明，干燥阶段前驱体的部分氧化有效增强了锰的氧化态。该策略成功地抑制了后续煅烧过程中锰的相互扩散，从而在最终的正极材料中保留了核/壳结构。这种优化的结构减轻了界面反应，增强了化学机械性能，并减少了串扰（串扰是导致侧翻失败的主要原因）。这项工作提出了一种合成下一代锂离子电池高性能核/壳正极材料的新方法。