High energy density and lofty thermal stability nickel-rich materials for positive electrode of lithium ion batteries

作者：Mezaal, Mohammed Adnan; Qu, Limin; Li, Guanghua; Liu, Wei; Zhao, Xiaoyuan; Fan, Zhenzhen; Lei, Lixu^*

来源：Journal of Solid State Electrochemistry, 2017, 21(8): 2219-2229.

DOI：10.1007/s10008-017-3564-9

• Nickel-rich materials
• Core-shell structure
• Thermal stability
• Li2MnO3
• Lithium ion battery
• Energy density

Ni-rich LiNi0.8Mn0.1Co0.1O2 (NCM811) is one of the most promising electrode materials for Lithium-ion batteries (LIBs). However, its instability at potentials higher than 4.3 V hinders its use in LIBs. To overcome this barrier, we have prepared a core-shell material composed of a core of NCM811 (R-3m) and a monoclinic (C2/m) Li2MnO3 shell. The structure is confirmed by XRD, TEM, and XPS. This core-shell is very different from the conventional core-shell materials. In comparison, the conventional core-shell materials are layered R-3m structures which are instable at highly delithiated state (> 4.5 V) due to the high repulsion between the two oxygen atoms facing each other across the empty Li site, while our synthesized material can be safely cycled at high upper cut-off potential of 4.7 V with high capacity retention. Compared to previously reported materials, the materials show substantially improved performance in terms of discharge capacity, energy density, and thermal stability. The upper cut-off potential is elevated from 4.3 to 4.7 V. Differential scanning calorimetry (DSC) results show that the exothermic peak of the core-shell structured material appears at 360 A degrees C with a heat evolution of 575.1 J g(-1), while that of the pristine material appears at 250 A degrees C with a heat evolution of 239.1 J g(-1).

• 出版日期2017-8
• 单位东南大学