Title Page
Abstract
Contents
Chapter 1. Effect of novel ionic additives on the performance of lithium batteries 11
1.1. Introduction 11
1.2. Experimental 13
1.2.1. Materials 13
1.2.2. Synthesis of ionic additives 13
1.2.3. Synthesis of DA homopolymer 14
1.2.4. Preparation of electrolytes 14
1.2.5. Preparation of cathode and cell assembly 14
1.2.6. Characterization of battery cells 15
1.3. Results and Discussion 16
1.4. Conclusions 29
1.5. References 30
국문초록 33
Table 1.1. Characteristics of ionic and non-ionic additive-containing cells. 19
Figure 1.1. (a) Schematic illustration of effects of PDA (non-ionic) (left) and PAATFSI (ionic) (right) additives. Chronoamperometry profiles and Nyquist... 16
Figure 1.2. Difference in FTIR spectra depending on the presence of PAATFSI: a shift of (a) C-N vibration peak of cation moiety of PAATFSI (1489 to 1491... 18
Figure 1.3. Temperature dependence of ionic conductivity for the electrolyte with and without PAATFSI additive. To extract the activation energy, the result was... 20
Figure 1.4. Effect of the PAATFSI additive on the frequency dependent viscosity of electrolytes. 21
Figure 1.5. Chronoamperometry profiles and Nyquist plots (insets) of Li/Li symmetric cells with 1 M LiPF₆ in EC/DMC (1:1 vol). 21
Figure 1.6. Electrodeposition stability of Li metal electrodes with different electrolytes. (a) Voltage profiles of Li/Li symmetric cells at a fixed current density... 23
Figure 1.7. Electrodeposition stability of Li metal electrodes with different electrolytes. Voltage profiles of Li/Li symmetric cells were acquired at current... 23
Figure 1.8. (a) Rate performances of Li/NCM811 cells with PDA and PAATFSI additives. Corresponding charge-discharge voltage profiles at various C-rates... 24
Figure 1.9. Voltage profiles of Li/NCM811 cells with non-ionic PDA additives at (a) 1.5 and (b) 2C-rates. Variations in voltage profiles of Li/NCM811 cells... 26
Figure 1.10. Additive effect on cycling performance of Li/NCM811 cell at (a) 1 C, (b) 2 C, and (c) 3 C rates. 27
Figure 1.11. SEM images of Li metal anode included in Li/Li symmetric cell: (a) before and (b) after 100 cycles with PAATFSI in the electrolyte, and (c)... 28
Figure 1.12. Dependence of linear sweep voltammetry profiles of the electrolyte on the presence of PAATFSI. There was no correlation between the... 28