Title Page
Contents
ABSTRACT 9
Ⅰ. Introduction 11
Ⅱ. Experimental procedure 14
2.1. Materials 14
2.2. Preparation of Pristine Ni-rich single-crystal cathode and Li₂MoO₄ coated Ni-rich single-crystal cathode. 14
2.3. Materials characterization 14
2.4. Electrochemical measurements 15
Ⅲ. Results and discussion 17
3.1. Synthesis and material characterizations 17
3.2. Electrochemical characterizations 25
3.3. High temperature storage test 30
3.4. Post-mortem analysis 36
3.5. Intermittent galvanostatic titration technique (GITT) analysis 39
Ⅳ. Conclusion 40
References 41
Appendix 49
Abstract (in Korean) 59
〈Table 1〉 Fitting results of the EIS spectra of Pristine SC NCM90 and 2wt% LMO@SC NCM90 shown in Figure 9 obtained after three formation cycles... 33
〈Figure 1〉 (a) FE-SEM image of 2wt% LMO@SC NCM90; (b) EDS mapping of Ni, Co, Mn, O, and Mo; (c) TEM and (d) HRTEM and local FFT images of... 18
〈Figure 2〉 (a) Mo 3d XPS spectra of 2wt% LMO@SC NCM90; (b) O 1s, (c) C 1s, and (d) Ni 2p XPS spectra of Pristine SC NCM90 and 2wt%... 20
〈Figure 3〉 (a) XRD patterns of Pristine SC NCM90 and various amounts (x wt%) of LMO@SC NCM90 and (b) magnified view of (003) reflection. 21
〈Figure 4〉 (a) Residual Li titration plot; (b) pH values of Pristine SC NCM90 and x wt% LMO@SC NCM90. 23
〈Figure 5〉 (a) Voltage profile for the initial cycle of Pristine SC NCM90 and xwt% LMO@SC NCM90 electrodes (0.1 C rate, 3.0–4.3 V); (b) rate... 25
〈Figure 6〉 Electrochemical performance comparison of Pristine SC NCM90 and xwt% LMO@SC NCM90 at 1C rate (at 25 ℃) in a voltage range... 28
〈Figure 7〉 Electrochemical performance comparison of Pristine SC NCM90 and 2wt% LMO@SC NCM90 (a) during the 60 ℃ high... 30
〈Figure 8〉 Comparison of effects of 60 ℃ high temperature exposure electrochemical performance of Pristine SC NCM90 and 2wt% LMO@SC... 32
〈Figure 9〉 C 1s, O 1s, and F 1s XPS spectra of Pristine SC NCM90 and 2wt% LMO@SC NCM90 after (a-c) three formation cycles (25 ℃) and (d-f)... 36
〈Figure 10〉 (a) GITT curves and calculated Lithium-ion diffusion coefficients (DLi₊) of Pristine SC NCM90 and 2wt% LMO@SC NCM90 (at... 39
〈Scheme 1〉 Schematic of the synthesis of Li₂MoO₄-coated single-crystal LiNi₀.₉Mn₀.₀₇Co₀.₀₃O₄ 17