Insights into the electrochemical Li/Na-exchange in layered LiCoO2 cathode material

Autor: Michael Schneider, Tobias Lein, Tobias Liebmann, C. Lämmel, Björn Matthey, Christian Heubner, Alexander Michaelis, Mathias Herrmann, Florian Wolke
Rok vydání: 2020
Předmět:
Zdroj: Energy Storage Materials. 27:377-386
ISSN: 2405-8297
DOI: 10.1016/j.ensm.2020.02.012
Popis: The electrochemical alkali ion exchange is a powerful technique to synthesize novel active materials for secondary batteries or to study Li/Na/K analogous intercalation compounds. Herein, we report for the first time the electrochemically conducted exchange of Li-ions by Na-ions within the host lattice of LiCoO2. Li–Na substitution in a potential range of 2.0–4.0 ​V vs. Na/Na+ leads to the formation of a Li/Na-mixed intercalation compound. Operando XRD measurements and ex-situ EDS-mappings indicate that the different ionic radii and the corresponding CoO2-layer distances forbid Li–Na mixing in the lattice, resulting in the emergence of Na- and Li-rich domains during Na-ion insertion. Charging and discharging of the resulting Li/Na-mixed intercalation compound is dominated by Na-insertion and extraction, while Li-ions remain in the lattice until it is completely depleted of Na-ions. These novel insights concerning competitive kinetics, thermodynamics and phase evolution behavior can be highly useful to understand similarities and differences of Na- and Li-insertion chemistries to develop materials for future Na-ion batteries based on the comprehensive scientific knowledge in Li-ion technology.
Databáze: OpenAIRE
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