期刊
ACS APPLIED MATERIALS & INTERFACES
卷 13, 期 38, 页码 45619-45629出版社
AMER CHEMICAL SOC
DOI: 10.1021/acsami.1c13908
关键词
lithium-rich layered oxides; niobium doping; TM-O covalency; structural and thermal stability; electrochemical performance
资金
- National Key Research and Development Program of China [2018YFB010400, 2017YFB0702100]
- Fundamental Research Funds for the Central Universities [020514380224]
- State Key Laboratory of Powder Metallurgy at Central South University
- Shenzhen GuoTuo Technology Co., Ltd.
The study proposes a method to improve the thermal stability and cycle life of Li1.2Mn0.53Ni0.27O2 cathode material for lithium-ion batteries by doping with niobium, showing potential for industrial application.
Lithium-rich manganese-based layered oxides (LLOs) are considered to be the most promising cathode materials for next-generation lithium-ion batteries (LIBs) for their higher reversible capacity, higher operating voltage, and lower cost compared with those of other commercially available cathode materials. However, irreversible lattice oxygen release and associated severe structural degradation that exacerbate under high temperature and deep delithiation hinder the large-scale application of LLOs. Herein, we propose a strategy to stabilize the layered lattice framework and improve the thermal stability of cobalt-free Li1.2Mn0.53Ni0.27O2 by doping with 4d transition metal niobium (Nb). Detailed atomic-scale imaging, in situ characterization, and DFT simulations confirm that the induced strong Nb-O bonds stabilize the oxygen lattice framework and restrains the fracture of TM-O bonds, thereby inhibiting the release of lattice oxygen and the continuous migration of TM ions to the lithium layer during the cycle. Furthermore, Nb doping also promotes the surface rearrangement to form a Ni-enrichment layered/rocksalt heterogeneous interface to enhance surface structural stability. As a result, the Nb-doped material delivers a capacity of 181.7 mAh g(-1) with retention of 85.5% after 200 cycles at 1C, extraordinary thermal stability with a capacity retention of 80.7% after 200 cycles at 50 degrees C, and superior rate capability.
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