리튬이온전지용 실리케이트 기반 다공성 실리콘과 표면 개질 MXene 복합 음극소재의 전기화학적 특성에 관한 연구 = A Study on the Electrochemical Characteristics of Silicate- Derived Porous Silicon and Surface-Modified MXene Composite Anodes for Lithium-Ion Batteries

다국어 초록 (Multilingual Abstract)

Driven by carbon-neutral policies and increasingly stringent emission regulations, the transition from internal-combustion vehicles to electric vehicles (EVs) has accelerated, continuously raising demands for longer driving range, faster charging capability, and greater cycle stability of batteries. However, the conventional graphite anode (theoretical capacity 372 mAh g-1) fundamentally limits the system-level energy density. As an alternative to overcome this limitation, silicon (Si) has attracted considerable attention as a next-generation high-capacity anode material owing to its high theoretical capacity of approximately 3579 mAh g-1 (Li15Si14) and low lithiation potential (≈ 0.4 V vs Li/Li+). Nevertheless, Si suffers from severe volume expansion exceeding 300 % during cycling, sluggish ionic and electronic transport, and unstable solid–electrolyte interphase (SEI) formation, which lead to deteriorated electrochemical kinetics and rapid capacity fading. To address these issues, this study designed a composite anode based on porous silicon (Reduced Magnesium Silicate, RMS) synthesized from magnesium silicate (MgSiO3) via magnesiothermic reduction, combined with MXene (Ti3C2Tx) functionalized by a carboxymethyl-cellulose–dopamine (CMC-DA) ligand. The RMS obtained from the precursor possesses a porous structure that mitigates the mechanical stress generated by Si expansion during cycling and shortens Li-ion diffusion pathways, thereby improving ionic transport. Meanwhile, the CMC-DA-modified MXene forms a robust conductive network and mechanical framework within the electrode. Its catechol-based surface groups promote strong interfacial bonding with RMS, enabling uniform and stable SEI formation and enhancing interfacial reaction kinetics. As a result, the fabricated f-MXene /RMS composite anode exhibits excellent electrochemical performance, maintaining a high reversible capacity of 719 mAh g-1 after 500 cycles at 1 C and 456.04 mAh g-1 at 5 C. These improvements demonstrate that the integration of Si’s high capacity with the superior electrical conductivity and mechanical robustness of MXene provides a promising strategy for developing high- energy-density and durable anodes for next-generation lithium-ion batteries.

목차 (Table of Contents)

• Ⅰ. Introduction 1
• Ⅱ. Experimental Section 3
• 1. Materials 3
• 2. Synthesis of Reduced Magnesium Silicate (RMS) 3
• 3. Preparation of Ti3C2Tx MXene 3
• 4. Preparation of CMC-DA 4
• 5. Preparation of CMC-DA-MXene (f-MXene) 4
• 6. Preparation of f-MXene/RMS 4
• 7. Material Characterization 5
• 8. Electrochemical Characterization 5
• Ⅲ. Results and Discussion 7
• Ⅳ. Conclusions 26