Analyzing the Mechanism of Functional Groups in Phosphate Additives on the Interface of LiNi0.8Co0.15Al0.05O2Cathode Materials

doi:10.1021/acsami.0c21535

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	Analyzing the Mechanism of Functional Groups in Phosphate Additives on the Interface of LiNi0.8Co0.15Al0.05O2Cathode Materials
	Wang, Jie; Zhao, Dongni; Cong, Yuanyuan; Zhang, Ningshuang; Wang, Peng; Fu, Xiaolan; Cui, Xiaoling
刊名	ACS Applied Materials and Interfaces
	2021-04-14
卷号	13 期号:14 页码:16939-16951
关键词	Additives Aluminum compounds Cathodes Chelation Chemical analysis Crosslinking Electrolytes Free energy Gibbs free energy Ionization potential Ligands Lithium-ion batteries Nickel compounds Oxalic acid Quantum chemistry Salts Advanced lithium-ion batteries Electrochemical impedance Electrochemical performance Functional electrolytes Gibbs free energy calculations Polymerization reaction Quantum chemistry calculations Vertical ionization potentials
ISSN号	1944-8244
DOI	10.1021/acsami.0c21535
英文摘要	The design of a functional electrolyte system that is compatible with the LiNi0.8Co0.15Al0.05O2 (LNCA) cathode is of great importance for advanced lithium-ion batteries (LIBs). In this work, chelated lithium salts of lithium difluoro(bisoxalato) phosphate (LiDFBOP) and lithium tetrafluoro(oxalate) phosphate (LTFOP) are synthesized by a facile and general method. Then, the complexes of LiDFBOP, LTFOP, and lithium difluorophosphate (LiDFP), all of which have a central phosphorus atom, were selected as the salt-type additives for the LiPF6-based electrolyte to improve the electrochemical performances of LNCA/Li half-batteries, respectively. The results of electrochemical tests, quantum chemistry calculations, potential-resolved in situ electrochemical impedance (PRIs-EIS) measurements, and surface analyses show that the interface property and the battery performance are closely associated with molecular structures of phosphorus-centered complex additives. It indicates that LiDFP with the PO bond can significantly reduce the interfacial impedance of LNCA/Li half-batteries due to the increase of Li3PO4 and the decrease of Li2CO3 in the cathode electrolyte interface (CEI). While in LiDFBOP, according to the calculated vertical ionization potential (VIP), the two oxalate-chelated ligands bring about a bidirectional cross-linking reaction, which makes it preferential to be oxidized. This process is self-healing and can form a dense and stretched CEI, which is favorable to the cycle performance at the late stage. In contrast, the polymerization reaction will occur in one direction for LTFOP due to its lone oxalate ligand. Additionally, an unfavorable side reaction between LTFOP and EC has been proposed by the aid of Gibbs free energy calculation. This is a good explanation for the formation of the uneven and unstable CEI, as well as the continuous decomposition of the electrolyte in PRIs-EIS measurement. This work has an extensive applicability and practical significance not only for molecular designing of novel lithium salts, but also for the construction of a functional electrolyte system that is compatible with different electrode materials. © 2021 American Chemical Society.
WOS研究方向	Science & Technology - Other Topics ; Materials Science
语种	英语
出版者	American Chemical Society
WOS记录号	WOS:000641156600096
内容类型	期刊论文
源URL	[http://ir.lut.edu.cn/handle/2XXMBERH/148428]
专题	石油化工学院
作者单位	College of Petrochemical Technology, Lanzhou University of Technology, Lanzhou; 730050, China
推荐引用方式 GB/T 7714	Wang, Jie,Zhao, Dongni,Cong, Yuanyuan,et al. Analyzing the Mechanism of Functional Groups in Phosphate Additives on the Interface of LiNi0.8Co0.15Al0.05O2Cathode Materials[J]. ACS Applied Materials and Interfaces,2021,13(14):16939-16951.
APA	Wang, Jie.,Zhao, Dongni.,Cong, Yuanyuan.,Zhang, Ningshuang.,Wang, Peng.,...&Cui, Xiaoling.(2021).Analyzing the Mechanism of Functional Groups in Phosphate Additives on the Interface of LiNi0.8Co0.15Al0.05O2Cathode Materials.ACS Applied Materials and Interfaces,13(14),16939-16951.
MLA	Wang, Jie,et al."Analyzing the Mechanism of Functional Groups in Phosphate Additives on the Interface of LiNi0.8Co0.15Al0.05O2Cathode Materials".ACS Applied Materials and Interfaces 13.14(2021):16939-16951.