Turning commercial MnO2 (≥85 wt%) into high-crystallized K+-doped LiMn2O4 cathode with superior structural stability by a low-temperature molten salt method

Junfei Ma; Bei Long; Qing Zhang; Yuzhu Qian; Ting Song; Wenyuan He; Manjun Xiao; Li Liu; Xianyou Wang; Yexiang Tong

doi:10.1016/j.jcis.2021.10.113

Turning commercial MnO₂ (≥85 wt%) into high-crystallized K⁺-doped LiMn₂O₄ cathode with superior structural stability by a low-temperature molten salt method

J Colloid Interface Sci. 2022 Feb 15;608(Pt 2):1377-1383. doi: 10.1016/j.jcis.2021.10.113. Epub 2021 Oct 23.

Authors

Junfei Ma¹, Bei Long², Qing Zhang¹, Yuzhu Qian¹, Ting Song¹, Wenyuan He³, Manjun Xiao⁴, Li Liu¹, Xianyou Wang¹, Yexiang Tong⁵

Affiliations

¹ National Base for International Science and Technology Cooperation, National Local Joint Engineering Laboratory for Key Materials of New Energy Storage Battery, Hunan Province Key Laboratory of Electrochemical Energy Storage and Conversion, School of Chemical Engineering and Technology, School of Chemistry, Xiangtan University, Xiangtan 411105, PR China.
² National Base for International Science and Technology Cooperation, National Local Joint Engineering Laboratory for Key Materials of New Energy Storage Battery, Hunan Province Key Laboratory of Electrochemical Energy Storage and Conversion, School of Chemical Engineering and Technology, School of Chemistry, Xiangtan University, Xiangtan 411105, PR China. Electronic address: longbei@xtu.edu.cn.
³ National Base for International Science and Technology Cooperation, National Local Joint Engineering Laboratory for Key Materials of New Energy Storage Battery, Hunan Province Key Laboratory of Electrochemical Energy Storage and Conversion, School of Chemical Engineering and Technology, School of Chemistry, Xiangtan University, Xiangtan 411105, PR China. Electronic address: hewenyuan@xtu.edu.cn.
⁴ National Base for International Science and Technology Cooperation, National Local Joint Engineering Laboratory for Key Materials of New Energy Storage Battery, Hunan Province Key Laboratory of Electrochemical Energy Storage and Conversion, School of Chemical Engineering and Technology, School of Chemistry, Xiangtan University, Xiangtan 411105, PR China. Electronic address: xmj0704@163.com.
⁵ The Key Lab of Low-Carbon Chemistry & Energy Conservation of Guangdong Province, MOE of the Key Laboratory of Bioinorganic and Synthetic Chemistry, KLGHEI of Environment and Energy Chemistry, School of Chemistry, Sun Yat-sen University, Guangzhou 510275, PR China.

PMID: 34742059
DOI: 10.1016/j.jcis.2021.10.113

Abstract

The obtainment of low-cost, easily prepared and high-powered LiMn₂O₄ is the key to achieve its wide application in various electronic devices. In this work, a mild and easily scaled molten salt method (KCl@LiCl) is utilized to convert commercial MnO₂ to the high-performance LiMn₂O₄. At the same reaction temperature, the molten salt method leads to the formation of K⁺-doped LiMn₂O₄ with higher crystallinity compared to the conventional solid state method, which contributes to the improved inner charge transfer. The Li₃PO₄ protective layer is coated on the surface of K⁺-doped LiMn₂O₄ to elevate the interfacial stability and the Li⁺ transfer on interface. Thus, the optimized electrode shows a higher specific discharge capacity (103/60 mAh g^-1 at 0.02/2 A g^-1) and a longer cyclic life (80 mAh g^-1 after 500 cycles at 0.5 A g^-1) compared to those of LiMn₂O₄ by solid state method (49/2 mAh g^-1 at 0.02/2 A g^-1 and 20 mAh g^-1 after 500 cycles at 0.5 A g^-1).

Keywords: Commercial MnO(2) (≥ 85 wt%); Good structural stability; In-situ K(+) doping; LiMn(2)O(4); Low-temperature molten salt method.