Structural insights into composition design of Li-rich layered cathode materials for high-energy rechargeable battery
Volume 51, Issue , Page 15–26
| Zhining Wei, Minghao Zhang, Bao Qiu, Yuhuan Zhou, Yinguo Xiao, Dong Zhou, Liang Yun, Cheng Li, Qingwen Gu, Wen Wen, Xiao Li, Xiaohui Wen, Zhepu Shi, Lunhua He, Ying Shirley Meng, Zhaoping Liu
Abstract: 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 Li2MnO3-like domain and enhance the oxygen redox activity thermodynamically, the fast and complete activation of the Li2MnO3-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 Li2MnO3-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, Li2MnO3-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 Li2MnO3-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.
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DOI: 10.1016/j.mattod.2021.10.020
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