NCM811 coat
208334180
Surface Coated LiNi0.8Co0.1Mn0.1O2 (NCM811) Cathode Materials by Al2O3, ZrO2, and Li2O 2B2O3 Thin Layers for Improving the Performance of Lithium Ion Batteries
In this paper, the precursor Ni0.8Co0.1Mn0.1(OH)2 is prepared by a co precipitation method. By mixing this material with LiOH in proportion and sintering twice under 500 and 800 respectively, the cathode material of LiNi0.8Co0.1Mn0.1O2 (NCM811) for lithium ion batteries (LIBs) is synthesized. To improve the performance of this NCM811 material, Al2O3, ZrO2 and LBO (Li2O 2B2O3) are respectively used to coat it by a wet chemical method. The effects of Al2O3, ZrO2 and LBO thin coating layers ~20~200 nm) on the morphology, structure and electrochemical property of NCM811 are studied using XRD, SEM, TEM, XPS, and electrochemical measurements. Coin LIBs are assembled with the uncoated, Al2O3 coated, ZrO2 coated and LBO coated NCM811 cathode materials for performance validation. The experiment results confirm that the charge discharge specific capacity, Coulomb efficiency, water absorption stability, cycle characteristics and resistance stability of the NCM811 cathode material can be significantly improved by coating it with LBO particularly. Therefore, the surface coating to the particles of cathode materials using LBO is expected to be an effective and practical modification method to improve the electrochemical performance of LIBs.
Front. Mater.
Hailin Zhang Jiaqiang Xu Jiujun Zhang
91680440
A modified co precipitation process to coat LiNi1/3Co1/3Mn1/3O2 onto LiNi0.8Co0.1Mn0.1O2 for improving the electrochemical performance
Abstract A modified LiNi1/3Co1/3Mn1/3O2 coating process is introduced to improve the electrochemical performance of LiNi0.8Co0.1Mn0.1O2 (LNCM811) The coating process is carried on a precursor, Ni0.8Co0.1Mn0.1(OH)2 (NCM811) rather than on LNCM811. Unlike the electro inert metal oxide coatings, the LiNi1/3Co1/3Mn1/3O2 (LNCM111) layer is electrochemically active and able to relieve reactions between the highly delithiated Li1 mNi0.8Co0.1Mn0.1O2 and the electrolyte on account of the decrease of nickel content in outer layer. The LNCM111 coated LNCM811 material shows superior electrochemical performance, with an initial discharge capacity of 153 mAh g 1 and capacity retention of 90% after 100 cycles at 2C rate between 2.8 and 4.3 V at 60 degC.
Xibin Lu Xinhai Li Zhixing Wang Huajun Guo Guochun Yan Xing Yin
202038906
LiPO2F2 as a LiPF6 Stablizer Additive to Improve the high temperature Performance of the NCM811/SiOx@C Battery
Fluoroethylene Carbonate (FEC) is an indispensable additive to improve the cycle stability of silicon cathode, but the incompatibility between FEC and LiPF6 seriously damages the high temperature performance of NCM811/SiOx@C. In this paper, the LiPO2F2, tris(trimethylsilyl) borate (TMSB) and tris(trimethylsilyl) phosphate (TMSP) were added as stabilizer to increase the compatibility between LiPF6 and FEC at elevated temperatures. The visual experiments show that the traditional LiPF6 stablizer additive, such as (TMSB) and (TMSP) additive, would accelerate the decomposition of LiPF6 when FEC is present in the electrolyte solution. However, the introduction of LiPO2F2 additive can effectively inhibits the decomposition of LiPF6, then obviously inhibits the side reactions and decrease the selfdischarge of the NCM811/SiOx@C pouch cells under high temperature storage conditions. The hightemperature (45C) cycling performance of pouch cells with LiPO2F2 additive is 90.3% for 200 cycles and the swelling ratio is only 1.96% after storage at 55 C for 7days, which are all far superior to the contrast sample.
International Journal of Electrochemical Science
Wenfeng Song
54518207
Significant improvement of electrochemical properties of AlF3 coated LiNi0.5Co0.2Mn0.3O2 cathode materials
Abstract The uniform and spherical LiNi 0.5 Co 0.2 Mn 0.3 O 2 particles were successfully coated with AlF 3 The structures and electrochemical properties of AlF 3 coated LiNi 0.5 Co 0.2 Mn 0.3 O 2 were characterized by various techniques. When the coating amount was 0.5 mol% the cathode showed enhanced cycling performance and rate capability compared to the pristine LiNi 0.5 Co 0.2 Mn 0.3 O 2 The AlF 3 coated LiNi 0.5 Co 0.2 Mn 0.3 O 2 /Li cell had capacity retention of 98% after 100 cycles even at 4 C over 2.8 4.5 V, while the pristine LiNi 0.5 Co 0.2 Mn 0.3 O 2 exhibited capacity retention of only 89% Moreover, the rate capability and cyclic performance at elevated temperature (55 degC) were also improved. Electrochemical impedance spectroscopy testing revealed the improved electrochemical performance, which could be considered that the AlF 3 coating layer can suppress the increase of impedance during the charging and discharging process by preventing directly contact of the highly delithiated active material with electrolyte.
Kai Yang Li-Zhen Fan Jia Guo Xuanhui Qu
93426682
Li2ZrO3 coated LiNi0.6Co0.2Mn0.2O2 for high performance cathode material in lithium ion battery
To improve the high rate capacity and cycle ability, Li2ZrO3 was successfully coated on LiNi0.6Co0.2Mn0.2O2 materials via wet chemical method. The crystal structure and electrochemical properties of the bare and coated material are studied by X ray diffractometry (XRD) scanning electron microscope (SEM) transmission electron microscopy (TEM) cyclic voltammetry, and electrochemical impedance spectroscopy (EIS) The XRD and SEM results indicated that the lattice structure of Li2ZrO3 coated materials was the same as the pristine one. Transmission electron microscopy showed that there was a thin Li2ZrO3 coating layer on the surface. Li2ZrO3 coating improves the rate performance and cycling stability. Within the cutoff voltage of 2.6 4.8 V, the 1 wt% Li2ZrO3 coated samples exhibited an initial discharge capacity of 190 mAh g 1 and with a capacity retention about 85 after 50 cycles at 0.1 C. Minor Li2ZrO3 modification plays an important role to enhance the high rate capability and cycle ability of LiNi0.6Co0.2Mn0.2O2.
Ionics
Shuting Sun Chenqiang Du Deyang Qu Xin-he Zhang Zhi-yuan Tang
92031570
Excellent high rate capability and high voltage cycling stability of Y2O3 coated LiNi0.5Co0.2Mn0.3O2
Abstract Y2O3 coated LiNi0.5Co0.2Mn0.3O2 cathode materials show excellent cycling stability and higher rate capability than the bare LiNi0.5Co0.2Mn0.3O2 at higher cut off voltages of 4.6 V and 4.8 V. The thickness of Y2O3 coating layer is about 5 15 nm, and the original structure of the LiNi0.5Co0.2Mn0.3O2 isn't influenced by Y2O3 coating layer. The 2 wt% Y2O3 coated LiNi0.5Co0.2Mn0.3O2 can deliver 114.5 mAh g 1 (76.3% of its initial discharge capacity) after 100 cycles at 10C (1800 mA g 1) between 2.8 and 4.6 V, while the bare LiNi0.5Co0.2Mn0.3O2 delivers only 11.5 mAh g 1 with 8.3% capacity retention left. When the high cut off voltage increases to 4.8 V, the capacity retention of 2 wt% Y2O3 coated sample is 49.0% which is much higher than that of the bare sample (5.9% at 10C after 100 cycles. The rate capabilities of 2 wt% Y2O3 coated LiNi0.5Co0.2Mn0.3O2 are also improved significantly, especially at high rates (10C and 20C) X ray diffraction (XRD) and X ray photoelectron spectroscopy (XPS) are carried out to confirm the existence of Y2O3 layer on the LiNi0.5Co0.2Mn0.3O2 surface. Electrochemical impedance spectroscopy (EIS) and transmission electron microscopy (TEM) are applied to analyze the role of Y2O3 coating layer on the long cycling life and high rate capability.
Xuehui Liu Liangang Kou Tingjing Shi Kun Liu Li Chen
138313437
Improved high voltage electrochemical performance of Li2ZrO3 coated LiNi0.5Co0.2Mn0.3O2 cathode material
Abstract The use of Li2ZrO3 as an effective coating to enhance the cycling performance and rate capability of LiNi0.5Co0.2Mn0.3O2 cathode material under high cut off voltage of 4.6 V has been demonstrated. The structural and morphological characteristics of the bare and coated samples were investigated by X ray diffraction, scanning electron microscopy, transmission electron microscopy and X ray photoelectron spectroscopy. Electrochemical studies on bare and Li2ZrO3 coated LiNi0.5Co0.2Mn0.3O2 samples were conducted using galvanostatic charge discharge, cyclic voltammetry and electrochemical impedance spectroscopy by constructing a lithium half cell. It has been found that the high cut off voltage electrochemical performances of LiNi0.5Co0.2Mn0.3O2 cathode material are obviously improved by Li2ZrO3 surface modification. Notably, the 1 wt. Li2ZrO3 coated sample exhibits a capacity retention of 87.1% at 1C after 100 cycles, while that of bare one is 72.8% The cyclic voltammograms and impedance spectra results shown that the Li2ZrO3 coating reduced the polarization and improved the electrochemical activity of cathode. DSC tests reveal that the Li2ZrO3 coating layer also helps in enhancing the thermal stability of LiNi0.5Co0.2Mn0.3O2 cathode. Thus the Li2ZrO3 coated LiNi0.5Co0.2Mn0.3O2 indicates potential lithium ion batteries for high power applications even at high operating voltage.
Ding-Teng Wang Xinhai Li Zhixing Wang Huajun Guo Zhenjun Huang L Y Kong Juanjian Ru
96631151
Lithium active molybdenum trioxide coated LiNi0.5Co0.2Mn0.3O2 cathode material with enhanced electrochemical properties for lithium ion batteries
Abstract LiNi 0.5 Co 0.2 Mn 0.3 O 2 cathode material was coated with MoO 3 via a wet coating process. X ray diffraction patterns show that the coating surface is composed of MoO 3 and Li 2 MoO 4 The 3 wt. MoO 3 coated LiNi 0.5 Co 0.2 Mn 0.3 O 2 cathode (Li 2 MoO 4 is treated as equivalent mole of MoO 3 exhibits the best improved cycling performance. It performs a capacity retention of 90.9% after 100 cycles while that of the pristine material is only 82.8% After being coated by 3 wt. MoO 3 the rate performance is also greatly enhanced and the charge transfer resistance is greatly decreased. The improvement of electrochemical performance is related to the fact that the coating layer diminishes the side reactions between the cathode and the electrolyte.
Feng Wu Jun Tian Yuefeng Su Yi-biao Guan Yi-Chun Jin Zhao Wang Tao He Li-ying Bao Shi Chen
104361665
Influence of annealing atmosphere on Li2ZrO3 coated LiNi0.6Co0.2Mn0.2O2 and its high voltage cycling performance
Abstract Layered Ni rich oxides have attracted much attention for the positive electrode in lithium ion batteries due to their low cost and high capacity. However, they still suffer from poor cycling and rate performance, especially at high voltage. In this work, LiNi0.6Co0.2Mn0.2O2 powders are surface modified by a Li2ZrO3 coating prepared under either dry air or oxygen. The effect of the coating atmosphere on the electrochemical properties of Li2ZrO3/LiNi0.6Co0.2Mn0.2O2 are systematically investigated by multiple structural characterization (synchrotron HRXRD, SEM, TEM, and XPS) and electroanalytical (EIS, SSCV, and GITT) techniques. The Li2ZrO3 coating prepared in oxygen is largely amorphous. It not only provides surface protection against the electrolyte corrosion but also enables faster lithium ion transport at the interfacial regions. Additionally, oxygen atmosphere facilitates Zr diffusion from the surface coating to the bulk of LiNi0.6Co0.2Mn0.2O2, which stabilizes the crystal structure and enhances lithium ion diffusion. Consequently, LiNi0.6Co0.2Mn0.2O2 cathodes coated with Li2ZrO3 in oxygen exhibit improved high voltage cycling stability and high rate performance.
Electrochimica Acta
Xiaowen Zhan Shuang Gao Yang-Tse Cheng
105478234
Nitrogen doped carbon coated LiNi0.6Co0.2Mn0.2O2 cathode with enhanced electrochemical performance for Li Ion batteries
Abstract LiNi 0.6 Co 0.2 Mn 0.2 O 2 has attracted considerable attention as a high performance cathode material for lithium ion batteries due to its relatively high specific capacity and low cost. However, structural instability and side reactions at the surface, which occur during the charge/discharge process, largely limit its performance. Here, we introduce a nanoscale nitrogen doped carbon layer at the surface of the LiNi 0.6 Co 0.2 Mn 0.2 O 2 particles by using simple mechanical activation and pyrolysis methods. Systematic characterization indicates that a nitrogen doped carbon layer approximately 16 nm thick is uniformly coated on the LiNi 0.6 Co 0.2 Mn 0.2 O 2 particles. It has been proved beneficial to stabilize the layered structure of the LiNi 0.6 Co 0.2 Mn 0.2 O 2 with less cation disorder and residual lithium at the surface. The nitrogen doped carbon coated LiNi 0.6 Co 0.2 Mn 0.2 O 2 exhibited a capacity retention of 92% after 100 cycles from 3.0 to 4.5 V at 1 C, and a discharge capacity of 156 mAh g 1 at 5 C (78% of the capacity at 0.2 C) which is superior to the pristine LiNi 0.6 Co 0.2 Mn 0.2 O 2 in this work and most other reported LiNi 0.6 Co 0.2 Mn 0.2 O 2 cathodes. The improved electrochemical properties of the nitrogen doped, carbon coated cathode can be attributed to the higher degree of cation ordering, relieved side reactions between the cathode and electrolyte, and increased electronic conductivity.
Xian Chao Chen Feng Ma Yuyu Li Jiashun Liang Bryan Matthews Joshua Sokolowski Jiantao Han Gang Wu Xing Lu Qing Li