Please use this identifier to cite or link to this item: https://hdl.handle.net/10356/139020
Title: Dielectric polarization in inverse spinel‐structured Mg2TiO4 coating to suppress oxygen evolution of Li‐rich cathode materials
Authors: Zhang, Wei
Sun, Yonggang
Deng, Huiqiu
Ma, Jianming
Zeng, Yi
Zhu, Zhiqiang
Lv, Zhisheng
Xia, Huarong
Ge, Xiang
Cao, Shengkai
Xiao, Yao
Xi, Shibo
Du, Yonghua
Cao, Anmin
Chen, Xiaodong
Keywords: Engineering::Materials
Issue Date: 2020
Source: Zhang, W., Sun, Y., Deng, H., Ma, J., Zeng, Y., Zhu, Z., . . . Chen, X. (2020). Dielectric polarization in inverse spinel‐structured Mg2TiO4 coating to suppress oxygen evolution of Li‐rich cathode materials. Advanced Materials, 32(19), 2000496-. doi:10.1002/adma.202000496
Journal: Advanced Materials
Abstract: High‐energy Li‐rich layered cathode materials (≈900 Wh kg−1) suffer from severe capacity and voltage decay during cycling, which is associated with layered‐to‐spinel phase transition and oxygen redox reaction. Current efforts mainly focus on surface modification to suppress this unwanted structural transformation. However, the true challenge probably originates from the continuous oxygen release upon charging. Here, the usage of dielectric polarization in surface coating to suppress the oxygen evolution of Li‐rich material is reported, using Mg2TiO4 as a proof‐of‐concept material. The creation of a reverse electric field in surface layers effectively restrains the outward migration of bulk oxygen anions. Meanwhile, high oxygen‐affinity elements of Mg and Ti well stabilize the surface oxygen of Li‐rich material via enhancing the energy barrier for oxygen release reaction, verified by density functional theory simulation. Benefited from these, the modified Li‐rich electrode exhibits an impressive cyclability with a high capacity retention of ≈81% even after 700 cycles at 2 C (≈0.5 A g−1), far superior to ≈44% of the unmodified counterpart. In addition, Mg2TiO4 coating greatly mitigates the voltage decay of Li‐rich material with the degradation rate reduced by ≈65%. This work proposes new insights into manipulating surface chemistry of electrode materials to control oxygen activity for high‐energy‐density rechargeable batteries.
URI: https://hdl.handle.net/10356/139020
ISSN: 0935-9648
DOI: 10.1002/adma.202000496
Rights: This is the peer reviewed version of the following article: Zhang, W., Sun, Y., Deng, H., Ma, J., Zeng, Y., Zhu, Z., . . . Chen, X. (2020). Dielectric polarization in inverse spinel‐structured Mg2TiO4 coating to suppress oxygen evolution of Li‐rich cathode materials. Advanced Materials, 32(19), 2000496-. doi:10.1002/adma.202000496, which has been published in final form at 10.1002/adma.202000496. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.
Fulltext Permission: embargo_20210521
Fulltext Availability: With Fulltext
Appears in Collections:MSE Journal Articles

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