TY - JOUR
T1 - Role of Ordered Ni Atoms in Li Layers for Li-Rich Layered Cathode Materials
AU - Yang, Moon Young
AU - Kim, Sangryun
AU - Kim, Kyungsu
AU - Cho, Woosuk
AU - Choi, Jang Wook
AU - Nam, Yoon Sung
N1 - Funding Information:
This work was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT & Future Planning (Grant No. NRF-2016R1A2B4013045).
PY - 2017/9/20
Y1 - 2017/9/20
N2 - Li-rich layered oxide materials are promising candidates for high-energy Li-ion batteries. They show high capacities of over 200 mAh g−1 with the additional occupation of Li in their transition metal layers; however, the poor cycle performance induced by an irreversible phase transition limits their use in practical applications. In recent work, an atomic-scale modified surface, in which Ni is ordered at 2c sites in the Li layers, significantly improves the performance in terms of reversible capacity and cycling stability. The role of the incorporated Ni on this performance, however, is not yet clearly understood. Here, the effects of the ordered Ni on Li battery performance are presented, based on first-principles calculations and experimental observations. The Ni substitution suppresses the oxygen loss by moderating the oxidation of oxygen ions during the delithiation process and forms bonds with adjacent oxygen after the first deintercalation of Li ions. These NiO bonds contribute to the formation of a solid surface, resulting in the improved cycling stability. Moreover, the multivalent Ni suppresses Mn migration to the Li-sites that causes the undesired phase transition. These findings from theoretical calculations and experimental observations provide insights to enhance the electrochemical performance of Li-rich layered oxides.
AB - Li-rich layered oxide materials are promising candidates for high-energy Li-ion batteries. They show high capacities of over 200 mAh g−1 with the additional occupation of Li in their transition metal layers; however, the poor cycle performance induced by an irreversible phase transition limits their use in practical applications. In recent work, an atomic-scale modified surface, in which Ni is ordered at 2c sites in the Li layers, significantly improves the performance in terms of reversible capacity and cycling stability. The role of the incorporated Ni on this performance, however, is not yet clearly understood. Here, the effects of the ordered Ni on Li battery performance are presented, based on first-principles calculations and experimental observations. The Ni substitution suppresses the oxygen loss by moderating the oxidation of oxygen ions during the delithiation process and forms bonds with adjacent oxygen after the first deintercalation of Li ions. These NiO bonds contribute to the formation of a solid surface, resulting in the improved cycling stability. Moreover, the multivalent Ni suppresses Mn migration to the Li-sites that causes the undesired phase transition. These findings from theoretical calculations and experimental observations provide insights to enhance the electrochemical performance of Li-rich layered oxides.
KW - Li-rich layered oxides
KW - first-principles calculations
KW - oxygen loss
KW - phase transition
KW - surface modification
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U2 - 10.1002/adfm.201700982
DO - 10.1002/adfm.201700982
M3 - Article
AN - SCOPUS:85026527203
VL - 27
JO - Advanced Functional Materials
JF - Advanced Functional Materials
SN - 1616-301X
IS - 35
M1 - 1700982
ER -