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On the Beneficial Impact of Li 2 CO 3 as Electrolyte Additive in NCM523 ∥ Graphite Lithium Ion Cells Under High‐Voltage Conditions
Author(s) -
Klein Sven,
Harte Patrick,
Henschel Jonas,
Bärmann Peer,
Borzutzki Kristina,
Beuse Thomas,
Wickeren Stefan,
Heidrich Bastian,
Kasnatscheew Johannes,
Nowak Sascha,
Winter Martin,
Placke Tobias
Publication year - 2021
Publication title -
advanced energy materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.08
H-Index - 220
eISSN - 1614-6840
pISSN - 1614-6832
DOI - 10.1002/aenm.202003756
Subject(s) - electrolyte , materials science , graphite , lithium (medication) , dissolution , battery (electricity) , electrochemistry , decomposition , chemical engineering , inorganic chemistry , deposition (geology) , metal , electrode , chemistry , metallurgy , organic chemistry , medicine , paleontology , power (physics) , physics , quantum mechanics , sediment , engineering , biology , endocrinology
Lithium ion battery cells operating at high‐voltage typically suffer from severe capacity fading, known as ‘rollover’ failure. Here, the beneficial impact of Li 2 CO 3 as an electrolyte additive for state‐of‐the‐art carbonate‐based electrolytes, which significantly improves the cycling performance of NCM523 ∥ graphite full‐cells operated at 4.5 V is elucidated. LIB cells using the electrolyte stored at 20 °C (with or without Li 2 CO 3 additive) suffer from severe capacity decay due to parasitic transition metal (TM) dissolution/deposition and subsequent Li metal dendrite growth on graphite. In contrast, NCM523 ∥ graphite cells using the Li 2 CO 3 ‐containing electrolyte stored at 40 °C display significantly improved capacity retention. The underlying mechanism is successfully elucidated: The rollover failure is inhibited, as Li 2 CO 3 reacts with LiPF 6 at 40 °C to in situ form lithium difluorophosphate, and its decomposition products in turn act as ‘scavenging’ agents for TMs (Ni and Co), thus preventing TM deposition and Li metal formation on graphite.