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Kinetic Limitations in Single‐Crystal High‐Nickel Cathodes
Author(s) -
Ge Mingyuan,
Wi Sungun,
Liu Xiang,
Bai Jianming,
Ehrlich Steven,
Lu Deyu,
Lee WahKeat,
Chen Zonghai,
Wang Feng
Publication year - 2021
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.202012773
Subject(s) - redox , nickel , single crystal , cathode , materials science , ionic bonding , lithium (medication) , kinetics , electrode , chemical engineering , electrochemistry , inorganic chemistry , ion , chemical physics , chemistry , crystallography , metallurgy , physics , quantum mechanics , medicine , organic chemistry , engineering , endocrinology
High‐nickel cathodes attract immense interest for use in lithium‐ion batteries to boost Li‐storage capacity while reducing cost. For overcoming the intergranular‐cracking issue in polycrystals, single‐crystals are considered an appealing alternative, but aggravating concerns on compromising the ionic transport and kinetic properties. We report here a quantitative assessment of redox reaction in single‐crystal LiNi 0.8 Mn 0.1 Co 0.1 O 2 using operando hard X‐ray microscopy/spectroscopy, revealing a strong dependence of redox kinetics on the state of charge (SOC). Specifically, the redox is sluggish at low SOC but increases rapidly as SOC increases, both in bulk electrodes and individual particles. The observation is corroborated by transport measurements and finite‐element simulation, indicating that the sluggish kinetics in single‐crystals is governed by ionic transport at low SOC and may be alleviated through synergistic interaction with polycrystals integrated into a same electrode.