Coating TiO 2 on lithium-rich Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O 2 material to improve its electrochemical performance

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ORIGINAL PAPER

Coating TiO2 on lithium-rich Li1.2Mn0.54Ni0.13Co0.13O2 material to improve its electrochemical performance Changkun Song 1 & Wangjun Feng 1 & Zhaojiao Shi 1 & Zhaoyu Huang 1 Received: 5 September 2020 / Revised: 17 November 2020 / Accepted: 21 November 2020 # Springer-Verlag GmbH Germany, part of Springer Nature 2020

Abstract In this paper, the sol-gel method was used first to obtain the layered cathode material Li1.2Mn0.54Ni0.13Co0.13O2, and then the nanoparticles of TiO2 were coated samples in via a wet chemical process. Finally, a systematic study of the different amounts of TiO2 materials coated was carried out. XRD and SEM analysis showed that these materials after TiO2 coating have a good layered structure and regular morphology, respectively. Experiments such as XPS and TEM showed that the TiO2 nanoparticles were evenly distributed on the surface of the particles, and no substantial changes were made to each transition metal elements. Through electrochemical testing, when the TiO2 coating amount is equal to 1.0%, the first discharge-specific capacity reaches 276.5 mAh/g at 0.1 C, and the Coulomb efficiency is also as high as 80.8%. Compared with the uncoated sample, when the coating amount is 1.0%, the TiO2 coating suppresses the lack of surface oxygen and makes the structure more stable. The electrochemical performance of the material has been significantly improved. Keywords Layered cathode materials . TiO2 coating . Capacity retention . Lithium-ion battery

Introduction With the development of the economy and the advancement of technology, people have put forward higher requirements on the safety performance, energy and power density, cycle performance, cost, and environmental friendliness of the battery. The specific capacity of the existing conventional cathode materials can no longer meet the increasing high specific energy and high specific power demand of secondary batteries [1–5]. With the continuous research and modification of existing cathode materials, it is found that in the research of doping modification of layered LiMnO2, if the content of transition metal is controlled so that the ratio to lithium content is less than 1, some composite oxides with special electrochemical properties can be synthesized, and their molecular formulas can be written as xLi2MnO3•(1-x)LiMO2 (M = Ni, Co, Mn, Fe, Ni1/2Mn1/2, Ni1/3Mn1/3Co1/3), known as lithiumrich cathode material [6–9]. Such materials have high

* Wangjun Feng [email protected] 1

School of Science, Lanzhou University of Technology, Lanzhou 730050, China

reversible-specific capacity (200–300 mAh/g), good cycle stability and thermal stability, high operating voltage, low cost, and environmental friendliness. Once discovered, it has attracted a lot of attention and extensive research, and is considered to be the most promising cathode material at present [6, 10–13]. Although the lithium-rich manganese oxide cathode material has many advantages, it still has the following disadvantages: (1) The irreversible process of oxygen release leads