First-Principles Calculations on the LiMSO4F/MSO4F (M = Fe, Co, and Ni) Systems

详细信息    查看全文

• 作者：Yongmao Cai ; Gang Chen ; Xiaoguang Xu ; Fei Du ; Zhe Li ; Xing Meng ; Chunzhong Wang ; Yingjin Wei
• 刊名：Journal of Physical Chemistry C
• 出版年：2011
• 出版时间：April 14, 2011
• 年：2011
• 卷：115
• 期：14
• 页码：7032-7037
• 全文大小：954K
• 年卷期：v.115,no.14(April 14, 2011)
• ISSN：1932-7455

文摘

Systematic first-principles calculations based on the density functional theory are carried out to discuss the crystal and electronic structures of the LiMSO₄F/MSO₄F (M = Fe, Co, and Ni) systems. It is shown that all of the LiMSO₄F compounds are in a high spin antiferromagnetic ground state. However, they transform to different ground states with Li⁺ extraction. LiFeSO₄F is a typical Mott-Hubbard insulator and then transforms to a charge-transfer insulator with Li⁺ extraction. The theoretical intercalation voltages of LiMSO₄F are 3.54 (Fe), 4.73 (Co), and 5.16 V (Ni), respectively, which are close to corresponding LiMPO₄ phosphates. First-principles calculations show that a significant amount of electron-charge transfer takes place on the oxygen anions with Li⁺ extraction, especially for LiCoSO₄F and LiNiSO₄F. This will lead to significant loss of oxygen from the material lattice which is an intrinsic drawback of LiMSO₄F due to the concerns of structural and thermal stabilities.