Precursor effects on structural ordering and electrochemical performances of Ni-rich layered LiNi0.8Co0.2O2 cathode materials for high-rate lithium ion batteries

摘要

Ni-rich layered oxides (LiNi1-xMxO2, M = Co, Mn, Al, etc., x 0.5) are demonstrated as practical cathode materials for high-energy and high-power lithium ion batteries. However, various synthetic factors affect the degree of the structural ordering of layered LiNi1-xMxO2 oxides and their electrochemical lithium storage performances. Herein, we intentionally evaluate the transition metal precursor effects on manipulating the structural ordering and associated electrochemical performances of the Ni-rich LiNi0.8Co0.2O2 cathode material. The transition metal precursor in a special phase of carbonate hydroxide hydrate, i.e., Ni0.8Co0.2(CO3)(1-a)(OH)(2a)center dot bH(2)O together with a tridimensional network structure is demonstrated as the desirable precursor as compared with different contrasts. The resulting LiNi0.8Co0.2O2 cathode material shows significantly enhanced ordered layered structure and reveals remarkable high-rate capability along with excellent cycling stability. The LiNi0.8Co0.2O2 cathodes can deliver 195, 148 and 128 mAh g(-1) at 0.1, 1 and 5 C rates (1 C = 200 mA g(-1)) and retain 95% of the initial discharge capacity after 100 electrochemical cycles at 1 C and 72% after 500 cycles at 5 C, respectively. This work sheds lights on understanding transition metal precursor effects on the synthetic control and maximizing electrochemical performances of Ni-rich layered cathode materials for high-rate lithium ion batteries (C) 2018 Elsevier Ltd. All rights reserved.