Temperature regulated poly(acrylic acid)-based silicon anode binders : tailoring hydrogen and ester networks

다국어 초록 (Multilingual Abstract)

Silicon (Si) anodes exhibit exceptional theoretical capacity but suffer from structural pulverization caused by dramatic volume changes derived from lithiation and delithiation cycles. Despite progress in binder development, integrating robust mechanical properties with high ionic conductivity in a single binder system remains a critical challenge due to the difficulty in optimal funtional monomer sequence architecture. Herein, a PAA-based crosslinking copolymer combining polyacrylic acid (PAA) and tartaric acid (Tar) was synthesized to be used as the Si anode binder. In the formulation, PAA serve as rigid monomer, and the synergistic effect of the crosslinked binder fulfills the integrated design of a rigid-flexible copolymer and thus enables the accommodation of external stress and high rate capacity of Si anodes. The combination of PAA and Tar endows the binder with a tensile strength as high as 40 Mpa, and a high cohesion strength. The electrochemical performance of the Si anodes constructed with the PAA-Tar binder are stabilized, and a retention capacity of 1,500 mAh g-1 at 0.5 C-rate after 300 cycles. These results indicate that Si with the aqueous PAA-Tar binder has promising prospects for practical application, and this design also provides a reference for solving the expansion problem of the Si materials.

목차 (Table of Contents)

• Chapter 1. INTRODUCION 1
• 1.1 Lithium−Ion Batteries (LIBs) 1
• 1.2 Lithium−Ion Batteries : High Capacity Electrode Materials 3
• 1.3 Silicon Anodes 11
• 1.3.1 Silicon Anodes 11
• 1.3.2 Issues of Silicon Anodes 13
• 1.3.3 Strategies for Silicon Anodes 15
• 1.3.4 Binder Design for Silicon Anodes 23
• 1.4 Goal of this research 25
• Chapter 2. EXPERIMENTAL 28
• 2.1 Materials 28
• 2.2 Preparation of Binder Solution 28
• 2.3 Film Fabrication 29
• 2.4 Electrode Fabrication 29
• 2.4.1 Synthesis of Si Electrodes with PTAR Binder 29
• 2.4.2 NCM811 Electrodes Fabrication 32
• 2.5 Material Characterization 32
• 2.6 Cell Assembly 35
• 2.7 Electrochemical Measurements 36
• 2.7.1 Half−Cell Electrochemical Tests 36
• 2.7.2 Full Cell Electrochemical Tests 36
• Chapter 3. RESULT AND DISCUSSION 38
• 3.1 Design of PTAR Binders 38
• 3.2 Notation of Si Electrodes with PTAR Binder 39
• 3.3 Characterization of PTAR Binders 41
• 3.4 Mechanical Performance of Binders 46
• 3.5 Adhesion and Mechanical Properties of Si Electrodes 48
• 3.6 Electrochemical Performance 51
• 3.7 Post−Mortem Analysis 55
• Chapter 4. CONCLUSION 62
• References 63
• Appendix 73
• Korean Abstract 78