ELECTROCHIMICA ACTA
·
2017
·
IF 4.798
Jiale Fu,Daobin Mu,Borong Wu,Jiaying Bi,Xiaojiang Liu,Yiyuan Peng,Yiqing Li,Feng Wu
Developing high-voltage Li ion batteries (LIBs) is an important trend to meet the requirement of high energy density battery . However, high voltage will cause a series of problems harming the cycle performance of LIBs at the same time. This work is to investigate the effect of inorganic substance Li 2 SiO 3 on the electrochemical performance of LiNi 0.6 Co 0.2 Mn 0.2 O 2 (NCM622) cathode at high cutoff voltage of 4.6 V. XRD result shows that the structure of NCM622 cathode material is not affected by mixing Li 2 SiO 3 . However, XPS and EIS tests indicate that Li 2 SiO 3 has an evident influence on suppressing the decomposition of LiPF 6 and carbonate solvents at high voltage, reducing interfacial solid film impedance and modifying electrode/electrolyte interface. In addition, Li 2 SiO 3 retards the transition metal dissolution by consuming HF. Therefore, it enhances the electrochemical properties of the NCM622 cathode significantly. The highest discharge capacity increases to 191.7 mA h g -1 by mixing Li 2 SiO 3 , compared with the value of 180 mA h g -1 in the case of NCM622 cathode. The NCM622 electrode mixed with Li 2 SiO 3 also exhibits a better capacity retention of 73.4% after 200 cycles and a high rate capability at 20C with the value of 89 mA h g -1 , in contrast with 62.2% and 31 mA h g -1 attained in the NCM622 cathode.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
International Journal of Electrochemical Science
·
2023
·
IF 1.5
Ruijia Diao,G.P. Nayaka,Chengyi Zhu,Xiaohua Yu,Yannan Zhang,Ju Rong,Xiao Wang,Yingjie Zhang,Peng Dong,Mingyu Zhang,Xi Yang,Zhaolin Zhan
A facile hydrothermal method is successfully developed for the synthesis of CePO4 coated LiNi0.6Co0.2Mn0.2O2 (NCM 622) cathodes. The as-prepared samples are characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), electrochemical workstation, electrochemical impedance spectroscopy (EIS) and inductively coupled plasma emission spectrometry (ICP). Compared to the pristine NCM 622 cathode, the rate capacity and cyclic performance are significantly improved after coating. Even under a 10 C charge/discharge rate, the initial discharge capacity of the 3.0-NCM sample is up to 95.2 mAh . g -1 . Furthermore, the as- prepared 3.0-NCM sample exhibits excellent cyclic performance with 96.8% capacity retention at 1 C under 55 o C after 100 cycles, while the pure NCM 622 only delivers poor capacity retention of 71.4%. The above conclusions can be characterized that CePO4 coating layer can effectively avert the secondary reaction between electrolyte and cathode material. In addition, the CePO4 coating layer can significantly suppress the dissolution of cathodes in the electrolyte, which contributes to the excellent rate performance and cycle stability.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
ELECTROCHIMICA ACTA
·
2017
·
IF 4.798
Hao Wang,Daming Sun,Xiang Li,Wujie Ge,Bangwei Deng,Meizhen Qu,Gongchang Peng
Three kinds of functional organosilicons electrolyte additives, i. e. octamethylcyclotetrasiloxane (D4), octamethylcyclotetrasiloxane (OMCTS) and 2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetra- siloxane (ViD4), are firstly used to produce high-performance LiNi 0.6 Co 0.2 Mn 0.2 O 2 cathode for rechargeable Lithium-ion batteries (NCM622/Li half-cell) at a high potential. The electrochemical performance tests at 4.5 V suggest that ViD4 is the most promising electrolyte additive than its counterparts. Moreover, the prepared NCM622/Li half-cell with 0.5 wt.% ViD4 exhibits an improved energy density of 187.2 mAh g −1 and a good discharge capacity retention of 83.6% at 1C rate after 150 cycles at 4.5 V, which is relatively higher than that with D4 (81.3%), OMCTS (81.9%) and much better than the bare electrolyte (76.1%). The electrochemical characterizations, density functional theory calculation and surface analysis provide strong evidences that combined effects of the Si-O bond and vinyl functional group in ViD4 can promote the formation of a uniform cathode electrolyte interphase (CEI) film. Moreover, the ViD4-incorporated CEI film effectively enhances the interfacial stability between the NCM622 cathode and the electrolyte by suppressing the continuous decomposition of carbonate-based electrolyte and the exfoliation of these decomposition products. Hence, the ViD4-containing electrolyte shows a promising potential for the application in high energy density lithium-ion batteries.
研究领域:
材料科学
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电化学
·
能源存储
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2021
·
IF 5.316
Wenqian Zhang,Li Xiao,Jiangfeng Zheng,Yuelian Zhong,Bo Shi,Han Chen,Haikuo Fu
The electrochemical properties and thermal stability of the LiNi 0.6 Co 0.2 Mn 0.2 O 2 (NCM622) material have been significantly improved by Nb 2 O 5 nanocoating. The electrochemical properties were researched systematically by various electrochemical tests, and the molar ratio of Nb 2 O 5 to NCM622 was evaluated as 0.5 mol%. Results showed that Nb 2 O 5 nanocoated sample exhibited good cyclic performance, whose capacity retention was 92.36%, whereas that of the bare NCM was only 87.59% after 200 cycles under 1C at 25 °C. In addition, the Nb 2 O 5 surface-coated sample exhibited a good discharge capacity of 164.05 mAh g −1 after 200 cycles under 1C at 60 °C. The result owing to the nano coating of Nb 2 O 5 , which greatly increased the thermal stability, thereby maintaining remarkable specific capacity even in high-temperature environments. The modified sample could maintain a relatively complete structure after cycling, whereas the bare sample had already collapsed. Based on the transmission electron microscopic images, the thickness of the coating layer was about 15 nm. The nanocoating of Nb 2 O 5 was prepared by solid-phase reaction. This method is simple and convenient, which is conducive to industrial production and commercialisation promotion. The Nb 2 O 5 surface coating can enhance the electrochemical properties of the cathode materials , as well as strengthen the thermal and structural stability, which can extend the battery life.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
International Journal of Electrochemical Science
·
2023
·
IF 1.5
Chengyi Zhu,Jianxiong Liu,Xiaohua Yu,Yingjie Zhang,Xiaodong Jiang,Peng Dong,Yannan Zhang
4-Bromoanisole (4BA) is recommended for LiNi0.6Co0.2Mn0.2O2 (NCM 622) cathode materials as a safety electrolyte additive. The effect of anti-overcharge on NCM 622 cathodes are analyzed by cyclic voltammetry, constant current charge and discharge, AC impedance and scanning electron microscopy (SEM) measurement. The overcharge test results show that 4BA can be effectively electropolymerized at 4.45 V (vs. Li/Li + ), which can consume the overcharge current and protect the working electrode from voltage runaway. The time for the voltage rising to the overcharge state is availably delayed from about 16 hours to about 37 hours. The strategy can block off further oxidation of the active material and electrolyte, and finally promote the overcharge tolerance of the Li-ion batteries. Moreover, it is also found that the use of 4BA as a safety electrolyte additive does not obviously effect the electrochemical performance of NCM 622 and can effectively improve its cycle stability at high cut-off voltage (4.7 V).
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
·
2020
·Vol. 167
·期 13
·130517
·
IF 3.721
Zhaoyu Wang,Lihua Jiang,Chen Liang,Chunpeng Zhao,Zesen Wei,Qingsong Wang
The overcharge issue still occupies a high safety risk for NCM cathode materials with less stable structure. In this work, an original overcharge protection electrolyte additive named as 3-fluoroanisol (3FA) is recommended for NCM 622. The anti-overcharge effect of 3FA was verified in detail by cycle voltammetry, constant-current overcharge and discharge, AC impendence and scanning electron microscopy measurement. The electrolyte conductivity and long-term cycle performance tests were conducted to evaluate the impact of 3FA on the cell system operated in conventional voltage range. The 3FA is electro-polymerized at about 4.4 V and the time from upper cut-off voltage to overcharge state is extended from 5.46 h to 11.82 h in CR2032 cell, no adverse effects are shown during normal use at the same time under the additive amount of no more than 5 wt.%. Moreover, C80 micro-calorimeter test shows that 3FA increases thermal stability of electrolyte and NCM 622 cathode system. The heat production during overcharge was measured further. With the increase of the amount of 3FA added, the heat production during overcharge increases and the peak heat release rate occurs near 4.4 V, which further proves the effect of overcharge protection of 3FA. Thus, 3FA enhances overcharge endurance and thermal stability of lithium-ion battery with NCM 622 cathode.
研究领域:
电化学
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材料科学
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能源存储
·
锂离子电池
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功能材料
·
电极材料
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）