Theoretical Study on Graphite and Lithium Metal as Anode Materials for Next-Generation Rechargeable Batteries

ISBN-13: 9789811389160 / Angielski / Miękka / 2024

Gabin Yoon

Opis

This thesis describes in-depth theoretical efforts to understand the reaction mechanism of graphite and lithium metal as anodes for next-generation rechargeable batteries. The first part deals with Na intercalation chemistry in graphite, whose understanding is crucial for utilizing graphite as an anode for Na-ion batteries. The author demonstrates that Na ion intercalation in graphite is thermodynamically unstable because of the unfavorable Na-graphene interaction. To address this issue, the inclusion of screening moieties, such as solvents, is suggested and proven to enable reversible Na-solvent cointercalation in graphite. Furthermore, the author provides the correlation between the intercalation behavior and the properties of solvents, suggesting a general strategy to tailor the electrochemical intercalation chemistry. The second part addresses the Li dendrite growth issue, which is preventing practical application of Li metal anodes. A continuum mechanics study considering various experimental conditions reveals the origins of irregular growth of Li metal. The findings provide crucial clues for developing effective counter strategies to control the Li metal growth, which will advance the application of high-energy-density Li metal anodes.

Spis treści

1           Introduction      1

1.1        Demands for energy storage system     1

1.2        Li-ion batteries 1

1.3        Post Li-ion batteries      3

1.3.1     Na-ion batteries             3

1.3.2     Li metal batteries           5

1.4        References       6

2           Na intercalation chemistry in graphite   9

2.1        Introduction      9

2.2        Experimental and computational details            10

2.2.1     Materials           10

2.2.2     Electrode preparation and electrochemical measurements        10

2.2.3     Operando XRD analysis             11

2.2.4     Computational details   11

2.3        Staging behavior upon Na-solvent co-intercalation        12

2.4        Na-solvent co-intercalation into graphite structure        15

2.5        Solvent dependency on electrochemical properties       20

2.6        Conclusions     24

2.7        References       27

3           Conditions for reversible Na intercalation in graphite    31

3.1        Introduction      31

3.2        Computational details   32

3.3        Unstable Na intercalation in graphite    33

3.3.1     Destabilization energy of metal reconstruction 35

3.3.2     Destabilization energy of graphite framework upon intercalation           37

3.3.3     Local interaction between alkali metal ions and the graphite framework             37

3.3.4     Mitigating the unfavorable local interaction between Na and graphene layers             39

3.4        Conditions of solvents for reversible Na intercalation into graphite       41

3.4.1     Solvent dependency on reversible Na-solvent co-intercalation behavior             41

3.4.2     Thermodynamic stability of Na-solvent complex            43

3.4.3     Chemical stability of Na-solvent complex          46

3.4.4     Unified picture of Na-solvent co-intercalation behavior 47

3.5        Conclusions     48

3.6        References       48

4           Electrochemical deposition and stripping behavior of Li metal  53

4.1        Introduction      53

4.2        Computational details   55

4.3        Effect of deposition rate            57

4.4        Effect of surface geometry        60

4.5        Implications of SEI layer properties       63

4.6        Consequences of the history of deposition and stripping          70

4.7        Conclusions     72

4.8        References       72

O autorze

Dr. Gabin Yoon received a B.Sc. degree (2013) and Ph.D. degree (2019) in materials science and engineering from Seoul National University.

His research interest lies in the theoretical study of electrode materials for Li and Na rechargeable batteries using density functional theory and continuum mechanics. 

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