Cui Tianwei, Xu Jialiang, Wang Xin, Liu Longxiang, Xiang Yuxuan, Zhu Hong, Li Xiang, Fu Yongzhu
College of Chemistry, Zhengzhou University, Zhengzhou, 450001, China.
University of Michigan-Shanghai Jiao Tong University Joint Institute, Shanghai Jiao Tong University, Shanghai, 200240, China.
Nat Commun. 2024 Jun 4;15(1):4742. doi: 10.1038/s41467-024-48890-1.
The further practical applications of Li-rich layered oxides are impeded by voltage decay and redox asymmetry, which are closely related to the structural degradation involving irreversible transition metal migration. It has been demonstrated that the superstructure ordering in O2-type materials can effectively suppress voltage decay and redox asymmetry. Herein, we elucidate that the absence of this superstructure ordering arrangement in a Ru-based O2-type oxide can still facilitate the highly reversible transition metal migration. We certify that Ru in superstructure-free O2-type structure can unlock a quite different migration path from Mn in mostly studied cases. The highly reversible migration of Ru helps the cathode maintain the structural robustness, thus realizing terrific capacity retention with neglectable voltage decay and inhibited oxygen redox asymmetry. We untie the knot that the absence of superstructure ordering fails to enable a high-performance Li-rich layered oxide cathode material with suppressed voltage decay and redox asymmetry.
富锂层状氧化物的进一步实际应用受到电压衰减和氧化还原不对称性的阻碍，这与涉及不可逆过渡金属迁移的结构降解密切相关。已经证明，O2型材料中的超结构有序化可以有效抑制电压衰减和氧化还原不对称性。在此，我们阐明，基于Ru的O2型氧化物中不存在这种超结构有序排列仍可促进高度可逆的过渡金属迁移。我们证明，在无超结构的O2型结构中，Ru可以开启一条与大多数研究案例中的Mn截然不同的迁移路径。Ru的高度可逆迁移有助于阴极保持结构稳健性，从而实现出色的容量保持率，同时电压衰减可忽略不计，氧氧化还原不对称性也受到抑制。我们解开了一个谜团，即不存在超结构有序化无法实现具有抑制电压衰减和氧化还原不对称性的高性能富锂层状氧化物阴极材料。
