Improving the structural stability and electrochemical performance of Na2Li2Ti6O14 nanoparticles via MgF2 coating

Wei-Wei Ma; Hai-Tao Yu; Chen-Feng Guo; Ying Xie; Ning Ren; Ting-Feng Yi

doi:10.1039/c9ra02392e

Improving the structural stability and electrochemical performance of Na₂Li₂Ti₆O₁₄ nanoparticles via MgF₂ coating

RSC Adv. 2019 May 21;9(28):15763-15771. doi: 10.1039/c9ra02392e. eCollection 2019 May 20.

Authors

Wei-Wei Ma¹, Hai-Tao Yu¹, Chen-Feng Guo¹, Ying Xie¹, Ning Ren², Ting-Feng Yi³

Affiliations

¹ Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education, School of Chemistry and Materials Science, Heilongjiang University Harbin 150080 PR China xieying@hlju.edu.cn.
² Zhejiang Chilwee Chuangyuan Industry Co., Ltd Changxing Zhejiang 313100 PR China rnrm040412@163.com.
³ School of Resources and Materials, Northeastern University at Qinhuangdao Qinhuangdao 066004 PR China tfyihit@163.com.

Abstract

To improve their electrochemical performance and structural stability, Na₂Li₂Ti₆O₁₄ (NLTO) nanoparticles were synthesized and then coated with a very thin MgF₂ layer. Microscopy confirmed that the MgF₂-NLTO particles are about 150-250 nm in size, and that the thickness of the MgF₂ layer for the MgF₂-NLTO-5 sample is ∼5 nm. Electrochemical measurements showed that the charge-discharge specific capacities of the five samples under a current density of 50 mA g^-1 after 100 cycles are 110.4/110.7, 150.7/151.3, 181.1/182.1, 205.7/206.9 and 238.9/239.2 mA h g^-1, showing that the performance of MgF₂-NLTO-5 is the best among all the samples. Thanks to the thin coating layer, the polarization of the anode was reduced significantly, and its reversibility and lithium diffusion dynamics were also improved obviously. The performance improvement can be attributed to the suppression of surface corrosion and the enhancement of structural stability.