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Ni-rich layered cathodes for lithium-ion batteries are expected to be commercialized?!

2018-06-27 来源:亚科官网
27 June 2018
  Recently, researchers from the Pacific Northwest National Laboratory and the University of Western Ontario, Canada, obtained a layered Ni-rich cathode material with excellent cycling stability by regulating the grain boundary structure and chemical processes. The research results are published in the international journal Nature Energy, entitled "Tailoring grain boundary structures and chemistry of Ni-rich layered cathodes for enhanced cycle stability of lithium-ion batteries"[1].
  At present, LiNi1-xMxO2 (1-x>0.6; M=Co, Mn, Al, etc.) of lithium ion battery-rich cathode materials have high capacity and low cost and are considered to be the most promising alternatives to traditional materials [2]. However, The attenuation of capacity and voltage can easily occur, which has become a major challenge for the commercialization of this material due to the decomposition and lattice transformation: the nickel-rich cathodes material easily absorbs CO2 and H2O in the air,a side reaction occurs to generate Li2CO3 and LiOH impurities, and the reaction forms an insulating layer on the surface of the material; at the same time, Ni2+ migrates easily from the transition metal layer to the lithium layer, causing ion mixing and dissipating; the highly active Ni4+ also accelerates the decomposition of the electrolyte and leads to the exhaustion of the electrolyte. The conventional method of surface modification of positive particles can be partially alleviated, but it still cannot fundamentally solve the problem.
  The researchers first prepared Ni-rich layered cathode material (NMC) secondary particles, and then infuse the solid electrolyte (Li3PO4, LPO) by atomic layer deposition, and then annealled at high temperature 600°C, grain boundaries of cathode secondary particles NMC with a solid electrolyte LPO material is obtained.
  This method greatly improves the capacity retention and voltage stability of the cathode. The researchers found that the solid electrolyte injected at the boundary not only acts as a fast channel for lithium ion transport, but more importantly prevents the liquid electrolyte from penetrating into the grain boundary and eliminates the various side reactions, which includes the positive-liquid electrolyte interface reactions, interparticle cracks and phase transitions.
  The method greatly enhances the capacity retention rate and volume change stability of the cathodes material, and provides a new idea for the design and development of the advanced cathode material of the lithium ion battery. It is expected to realize the commercialization of Ni-rich layered cathodes for lithium-ion batteries.
[1] Pengfei Yan, Jianming Zheng, Xueliang Sun, Chongmin Wang, Ji-Guang Zhang et al. Tailoring grainboundary structures and chemistry of Ni-rich layered cathodes for enhanced cycle stability of lithium-ion batteries. Nature Energy 2018.
[2] Yan Liang, Wu Ti, Duan Jianguo. Surface chemistry and modification of nickel-rich cathode materials for lithium-ion batteries. Guangzhou Chemical Industry, 2017, 10, 12-13.
Edited by Suzhou Yacoo Science Co., Ltd.