Stabilizing the Electrode/electrolyte Interface of LiNi0.8Co0.15Al0.05O2 through Tailoring Aluminum Distribution in Microspheres as Long-life, High-rate and Safe Cathode for Lithium-ion Batteries.

Author(s) Hou, P.; Zhang, H.; Deng, X.; Xu, X.; Zhang, L.
Journal ACS Appl Mater Interfaces
Date Published 2017 Aug 07

The unstable electrode/electrolyte interface of high-capacity LiNi0.8Co0.15Al0.05O2 (NCA) cathodes, especially at highly delithiated state, usually leads to the transformation of layered to spinel and/or rock-salt phases, resulting in drastic capacity fade and poor thermal stability. Herein, the Al-increased and Ni, Co-decreased electrode surface is fabricated through tailoring element distribution in micron-sized spherical NCA secondary particles via co-precipitation and solid-state reactions, aimed at stabilizing the electrode/electrolyte interface during continuous cycles. As expected, it shows much extended cycle life, 93.6% capacity retention within 100 cycles, compared with that of 78.5% for the normal NCA. It also delivers large reversible capacity of about 140 mAh g-1 even at 20 C, corresponding to energy density of around 480 Wh Kg-1, which is enhanced by 45% compared to that of the normal NCA (about 330 Wh Kg-1). Besides, the delayed heat emission temperature and reduced heat generation mean remarkably improved thermal stability. These foregoing improvements are ascribed to the Al-increased spherical secondary particle surface that stabilizes the electrode/electrolyte interface by protecting inner components from directly contacting with electrolyte and suppressing the side reaction on electrode surface between high oxidizing Ni4+ and electrolyte.

DOI 10.1021/acsami.7b05986
ISSN 1944-8252
Citation ACS Appl Mater Interfaces. 2017.

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