A mechanistic investigation of the Li<sub>10</sub>GeP<sub>2</sub>S<sub>12</sub>|LiNi<sub>1-x-y</sub>Co<sub>x</sub>Mn<sub>y</sub>O<sub>2</sub> interface stability in all-solid-state lithium batteries.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 34795212.
- Also identified by DOI 10.1038/s41467-021-26895-4 and PMC identifier 8602263.
- Licence recorded as CC BY.
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Abstract
All-solid-state batteries are intensively investigated, although their performance is not yet satisfactory for large-scale applications. In this context, the combination of Li<sub>10</sub>GeP<sub>2</sub>S<sub>12</sub> solid electrolyte and LiNi<sub>1-x-y</sub>Co<sub>x</sub>Mn<sub>y</sub>O<sub>2</sub> positive electrode active materials is considered promising despite the yet unsatisfactory battery performance induced by the thermodynamically unstable electrode|electrolyte interface. Here, we report electrochemical and spectrometric studies to monitor the interface evolution during cycling and understand the reactivity and degradation kinetics. We found that the Wagner-type model for diffusion-controlled reactions describes the degradation kinetics very well, suggesting that electronic transport limits the growth of the degradation layer formed at the electrode|electrolyte interface. Furthermore, we demonstrate that the rate of interfacial degradation increases with the state of charge and the presence of two oxidation mechanisms at medium (3.7 V vs. Li<sup>+</sup>/Li < E < 4.2 V vs. Li<sup>+</sup>/Li) and high (E ≥ 4.2 V vs. Li<sup>+</sup>/Li) potentials. A high state of charge (>80%) triggers the structural instability and oxygen release at the positive electrode and leads to more severe degradation.