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Reversible High Capacity and Reaction Mechanism of Cr 2 (NCN) 3 Negative Electrodes for Li‐Ion Batteries
Author(s) -
Arayamparambil Jeethu Jiju,
Chen Kaixuan,
Iadecola Antonella,
Mann Markus,
Qiao Xianji,
Fraisse Bernard,
Dronskowski Richard,
Stievano Lorenzo,
Sougrati Moulay Tahar
Publication year - 2020
Publication title -
energy technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.91
H-Index - 44
eISSN - 2194-4296
pISSN - 2194-4288
DOI - 10.1002/ente.201901260
Subject(s) - electrochemistry , lithium (medication) , intercalation (chemistry) , transition metal , density functional theory , redox , reaction mechanism , electrode , chemistry , metal , inorganic chemistry , carbodiimide , materials science , computational chemistry , polymer chemistry , catalysis , organic chemistry , medicine , endocrinology
A detailed study of the electrochemical reaction mechanism between lithium and the trivalent transition‐metal carbodiimide Cr 2 (NCN) 3 , which shows excellent performance as a negative electrode material in Li‐ion batteries, is conducted combining complementary operando analyses and state‐of‐the‐art density functional theory (DFT) calculations. As predicted by DFT, and evidenced by operando X‐ray diffraction and Cr K‐edge absorption spectroscopy, a two‐step reaction pathway involving two redox couples (Cr 3+ /Cr 2+ and Cr 2+ /Cr 0 ) and a concomitant formation of Cr metal nanoparticles is apparent, thus indicating that the conversion reaction of this carbodiimide upon lithiation occurs only after a preliminary intercalation step involving two Li per unit formula. This mechanism, evidenced for the first time in transition‐metal carbodiimides, is likely behind its outstanding electrochemical performance as Cr 2 (NCN) 3 can maintain more than 600 mAh g −1 for 900 cycles at a high rate of 2 C.