This work presents findings on the mechanisms of hysteresis in lithium-rich cathode oxides. It is generally reported that the energy inefficiency, observed during electrochemical cycling of Li-rich electrodes, is a direct result of anion redox processes. Similarly, the coupled phenomenon of cation migration has been cited as being a mere consequence of that process with no essential ramification to hysteresis. Such works, however, have only shown correlations and not causation. Specifically, studies that clearly preclude the complete absence of either anion redox or cation migration (down to defect-level concentrations) are not reported yet. Herein, we present first principles calculations and experimental data on a bespoke Li-rich system that is indubitably immune to oxygen activity but yet exhibits significant energy inefficiency. Additionally, the results directly implicate transition metal migration as the fundamental, sole process responsible for hysteresis in this material. This study is of particular importance to the design and development of new Li-rich materials aimed at eliminating the role of oxygen and enhancing the effective cationic redox contribution to the capacity and points out the essential need to develop materials devoid of transition metal migration to interstitial sites in both layered and disordered oxides alike.

这项工作提出了富锂阴极氧化物中磁滞机理的发现。通常据报道，在富锂电极的电化学循环过程中观察到的能量效率低下是阴离子氧化还原过程的直接结果。同样，阳离子迁移的耦合现象被认为只是该过程的结果，对滞后没有实质性影响。但是，这些作品仅显示了相关性，而没有因果关系。具体而言，尚无报道明确排除完全不存在阴离子氧化还原或阳离子迁移（低至缺陷水平浓度）的研究。在这里，我们介绍了定制的富锂系统的基本原理计算和实验数据，该系统对氧气的活性具有不可抗拒的免疫力，但表现出明显的能量效率低下。另外，结果直接表明过渡金属迁移是造成这种材料滞后的基本，唯一的过程。这项研究对于旨在消除氧的作用并增强阳离子氧化还原对容量的有效贡献的新型富锂材料的设计和开发尤其重要，并指出了开发无过渡金属迁移到间隙中的材料的基本需求层状和无序氧化物中的位均相同。