Enhancing the electrochemical performance of SiOx anodes using nitrogen-doped carbon layer with copper nano beads from copper phthalocyanine carbonization
- 주제(키워드) SiOx , copper phthalocyanine , battery , volume expansion , cycle performance , carbon coating
- 발행기관 고려대학교 대학원
- 지도교수 김웅
- 지도교수 조원일
- 발행년도 2023
- 학위수여년월 2023. 8
- 학위구분 석사
- 학과 대학원 신소재공학과
- 세부전공 신소재공학 전공
- 원문페이지 64 p
- UCI I804:11009-000000277468
- DOI 10.23186/korea.000000277468.11009.0000122
- 본문언어 영어
초록/요약
The high theoretical capacity (~2000 mAhg-1) of silicon sub-oxide (SiOx, 1<x<2) can solve the low energy density issue of the graphite anode in Lithium-ion batteries. In addition, it has an advantage in volume expansion or side reactions compared to pure silicon or lithium metal, which are discussed as next-generation anode materials. However, the application to commercial produces is still a problem when the anode stability and low Coulombic efficiency have not been controlled. In order to enhance the performance of the SiOx electrode, we applied the nitrogen-doped carbon with copper layer (N-C/Cu) from copper phthalocyanine (Cu-PC). We coated SiOx with Cu nano beads and a nitrogen-doped carbon layer at once by using Cu-PC, which was carefully investigated through various material characteristics. A facile method of mixing with SiOx and Cu-PC, followed by thermal decomposition to obtain a modified surface SiOx with a N-C/Cu, is proposed. In particular, doped nitrogen and copper beads synergistically enhance lithium affinity and electric conductivity, enhancing the electrochemical performance in half-cell cycling, the SiOx/N-C/Cu composite shows longer cyclability with a high capacity (1095.5 mAg-1) after 200 cycles. In addition, full cell cycling with a graphite mixed anode (7.8 wt% of SiOx) and a commercial NCM811 cathode (4.1 mAh cm-2) shows stable cycle performance over 50 cycles. The practical applicability of advanced SiOx is reinforced by performance evaluations with graphite anode as well as with a commercial NCM 811 cathode (4.1mAh).
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TABLE OF CONTENTS
ABSTRACT i
국문 초록 iii
PREFACE v
TABLE OF CONTENTS vi
LIST OF TABLES vii
LIST OF FIGURES viii
CHAPTER 1. INTRODUCTION 1
CHAPTER 2. EXPERIMENTAL SECTION 8
2.1 Synthesis of SiOx/N-C/Cu 8
2.2 Material characterization 9
2.3 Electrochemical measurements 10
CHAPTER 3. RESULTS AND DISCUSSION 13
3.1 Characterization of SiOx/N-C/Cu 13
3.2 Electrochemical characterization of SiOx/N-C/Cu 25
3.3 Electrochemical performance of SiOx/N-C/Cu cell 33
3.4 Volume expansion of electrode 40
CHAPTER 4. CONCLUSION 43
REFERENCES 45
