Structural insights into composition design of Li-rich layered cathode materials for high-energy rechargeable battery,Materials Today

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Structural insights into composition design of Li-rich layered cathode materials for high-energy rechargeable battery
Materials Today ( IF 21.1 ) Pub Date : 2021-11-13 , DOI: 10.1016/j.mattod.2021.10.020
Chong Yin _{1,

2} , Zhining Wei _{1,

3} , Minghao Zhang ₄ , Bao Qiu _{1,

2} , Yuhuan Zhou _{1,

2} , Yinguo Xiao ₅ , Dong Zhou ₁ , Liang Yun ₁ , Cheng Li ₆ , Qingwen Gu ₁ , Wen Wen ₇ , Xiao Li _{1,

2} , Xiaohui Wen _{1,

2} , Zhepu Shi _{1,

8} , Lunhua He _{9,

10,

11} , Ying Shirley Meng ₄ , Zhaoping Liu _{1,

2}

Affiliation

Ningbo Institute of Materials Technology & Engineering (NIMTE), Chinese Academy of Sciences, Ningbo 315201, PR China
Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences (UCAS), Beijing 100049, PR China
School of Chemical Engineering and Technology, China University of Mining and Technology (CUMT), Xuzhou 221116, P. R. China
Department of NanoEngineering, University of California San Diego (UCSD), La Jolla, CA 92093, USA
School of Advanced Materials, Peking University, Shenzhen Graduate School, Shenzhen 518055, PR China
Neutron Scattering Division, Oak Ridge National Laboratory (ORNL), 1 Bethel Valley Road, Oak Ridge, TN 37831-6473, USA
Shanghai Synchrotron Radiation Facility, Chinese Academy of Sciences, Zhangjiang High-Tech. Park, Pudong New Area, Shanghai 201204, PR China
University of Nottingham Ningbo China (UNNC), Taikang East Road 199, Ningbo 315100, P. R. China
Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, PR China
Spallation Neutron Source Science Center, Dongguan 523803, PR China
Songshan Lake Materials Laboratory, Dongguan 523808, PR China

The Li-rich layered oxide is considered as one of the most promising cathode materials for high energy density batteries, due to its ultrahigh capacity derived from oxygen redox. Although incorporating over-stoichiometric Li into layered structure can generate LiMnO-like domain and enhance the oxygen redox activity thermodynamically, the fast and complete activation of the LiMnO-like domain remains challenging. Herein, we performed a systematic study on structural characteristics of Li-rich cathode materials to decipher the factors accounting for activation of oxygen redox. We reveal that the activation of Li-rich cathode materials is susceptible to local Co coordination environments. The Co ions can intrude into LiMnO-like domain and modulate the electronic structure, thereby facilitating the activation of Li-rich layered cathode materials upon first charging, leading to higher reversible capacity. In contrast, LiMnO-like domain hardly contains any Ni ions which contribute little to the activation process. The optimum composition design of this class of materials is discussed and we demonstrate a small amount of Co/Mn exchange in LiMnO-like domain can significantly promote the oxygen redox activation. Our findings highlight the vital role of Co ions in the activation of oxygen redox Li-rich layered cathode materials and provide new insights into the pathway toward achieving high-capacity Li-rich layered cathode materials.

中文翻译：

高能充电电池富锂层状正极材料成分设计的结构见解

富锂层状氧化物由于其源自氧氧化还原的超高容量而被认为是高能量密度电池最有前途的正极材料之一。尽管将超化学计量的锂结合到层状结构中可以产生类LiMnO结构域并增强热力学上的氧氧化还原活性，但快速且完全地激活类LiMnO结构域仍然具有挑战性。在此，我们对富锂正极材料的结构特征进行了系统研究，以破译氧氧化还原活化的因素。我们发现，富锂正极材料的活化容易受到局部钴配位环境的影响。 Co离子可以侵入类LiMnO结构域并调节电子结构，从而促进富锂层状正极材料在首次充电时的活化，从而获得更高的可逆容量。相比之下，LiMnO 类域几乎不含任何对活化过程贡献很小的 Ni 离子。讨论了此类材料的最佳成分设计，并证明类 LiMnO 域中少量的 Co/Mn 交换可以显着促进氧氧化还原活化。我们的研究结果强调了Co离子在氧氧化还原富锂层状正极材料活化中的重要作用，并为实现高容量富锂层状正极材料的途径提供了新的见解。

更新日期：2021-11-13

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