Performance Enhancement of Lithium-Ion Full Cells Using LNMO Cathode and Silicon Anode = LNMO 양극과 실리콘 음극을 이용한 리튬 이온 풀 셀의 성능 향상

다국어 초록 (Multilingual Abstract)

LiNi0.5Mn1.5O4(LNMO), a high-voltage spinel cathode, and silicon (Si), a high-capacity anode, have attracted considerable attention as next-generation material candidates due to their high operating voltage and excellent theoretical capacity. However, LNMO suffers from Mn3+-induced side reactions and structural instability, while Si suffers from severe interfacial degradation caused by excessive volume expansion. In this study, Zr doping was applied to the LNMO cathode (Zr-LNMO) and a 1,3,5-Trioxane/LiODFB/FEC based electrode surface coating (TXE-Si) was introduced to pure Si electrodes to enhance the structural and interfacial stability of each material. Zr-doped LNMO synthesized via co-precipitation showed reduced cation mixing and decreased Mn3+ content, resulting in improved structural stability. In addition, the formation of truncated-octahedral particles with increased exposure of the (100) facet facilitated Li⁺ diffusion, contributing to enhanced electrochemical performance. As a result, Zr0.1-LNMO exhibited a significant improvement in cycling retention, increasing from 43.1% to 76.7%, along with improved rate capability compared with the bare LNMO. For the Si anode, the applied surface coating enabled the formation of a stable LiF-rich SEI, reducing the volume expansion from 180% to 135% and mitigating structural degradation. As a result, the coated Si electrode achieved approximately 90% capacity retention, indicating substantially enhanced cycling stability relative to the reference electrode. The full cell composed of Zr-LNMO and TXE-Si exhibited improvements in initial discharge capacity, rate capability, long-term cycling retention, and energy density compared with the reference full cell. These results indicate that applying doping to the cathode and coating to the anode is an effective design strategy for realizing lithium-ion batteries with high energy density and excellent stability.

목차 (Table of Contents)

• List of Figures Ⅰ
• List of tables Ⅱ
• Abstract Ⅲ
• 1. INTRODUCTION 1
• A. Background 1
• 2. Theoretical background 3
• A. Overview and operation principle of lithium ion battery 3
• B. Cathode & Anode for high energy density 4
• C. Cathode material 6
• 1) Olivine Structure 6
• 2) Layered Structure 6
• 3) Spinel Structure 7
• D. High voltage cathode of LiNi0.5Mn1.5O4 8
• 1) Characteristic of LNMO 10
• 2) Strategies to Improve of LNMO 10
• E. Anode material 11
• 1) Artificial Graphite 11
• 2) Natural Graphite 12
• 3) Silicon 12
• F. Silicon 13
• 1) Characteristic of Silicon 13
• 2) Strategies to Improve Silicon Anodes 14
• G. Full cell 14
• 3. Experiment 16
• A. Zr Doping to Improve the Performance of LiNi0.5Mn1.5O4 Cathode 16
• 1) Synthesis of Zr-Doped LNMO. 16
• 2) Electrochemical Characterization. 18
• 3) Material Characterization. 18
• B. Coating protective layer to Improve cycle Performance For Pure silicon electrode 20
• 1) Electrode suface coating of Silicon. 20
• 2) Material Characterization. 22
• 4. Experiment 23
• A. Zr Doping to Improve the Performance of LiNi0.5Mn1.5O4 Cathode 23
• B. Coating protective layer to Improve cycle Performance For Pure silicon electrode 35
• C. Full cell performance with combined LNMO and Silicon improvement
• 43
• 5. CONCLUSIONS 44
• References 45
• 국문초록 51