Surface heterostructure induced by TiO2 modification in Li-rich cathode materials for enhanced electrochemical performances. (1st September 2020)

• Record Type: Journal Article
• Authors: Ran, Xinxin; Tao, Jianming; Chen, Ziyan; Yan, Zerui; Yang, Yanmin; Li, Jiaxin; Lin, Yingbin; Huang, Zhigao
• Is Part Of: Electrochimica acta. Volume 353(2020)
• Publication Date: 2020-09-01
• Subjects: Lithium-ion batteries -- Lithium-rich cathode -- Work function -- Thermal stability -- Built-in electric field; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2020.135959
• Languages: English
• ISSNs: 0013-4686

Abstract

Abstract: Building stable interfacial structure is highly desirable for high-voltage lithium rich cathode materials for lithium ion batteries. Heterostructure interface should play a crucial role in controlling electrochemical performances of Li-rich oxides. Herein, Li1.2 Ni0.13 Co0.13 Mn0.54 O2 nanoparticles are massively prepared via a facile ultrasonic spraying method, followed by surface-modification with TiO2 ultrathin layer using low-temperature hydrolysis technique. Comparing to pristine Li1.2 Ni0.13 Co0.13 Mn0.54 O2, TiO2 -coated composites exhibit better electrochemical performances in terms of rate capability, cycling stability and thermal stability. Li1.2 Ni0.13 Co0.13 Mn0.54 O2 @TiO2 composites deliver a reversible discharge capacity of 194.9 mAh▪g −1 at 25 °C and 257.8 mAh▪g −1 at 55 °C after 100 cycles, while the pristine Li1.2 Mn0.52 Ni0.13 Co0.13 O2 only has a discharge capacity of 208.4 mAhg −1 and 253.9 mAhg −1 respectively. The TiO2 -coating could reduce the work function of the hybrid composites and efficiently suppress the evolution of a solid electrolyte interface film at the electrode/electrolyte as well as improve thermal stability. Moreover, the built-in electric field originating from the difference in work function at the hetero-junction interface, would also facilitate electron-transfer and Li-ion migration across the hetero-junction interface and consequently robust electrochemical performances. Graphical abstract: Image 104634 Highlights: Heterostructural Li1.2 Ni0.13 Co0.13 Mn0.54 O2 @TiO2 composites are prepared via low-temperature hydrolysis. The electrochemical performances are improved by TiO2 -coating in terms of rate capability, cycling stability and thermal stability. The different in work function of composite facilitates charges across the heterojunction interface and relieves electrolyte decomposition.