리튬 이온 배터리용 SiOx 기반 음극재의 성능 향상: 금속 도핑 전략과 실용화 가능성에 대한 총설

초록

Silicon (Si) is widely considered a promising anode material for high-energy-density lithium-ion batteries (LIBs) owing to its exceptionally high theoretical capacity (~3579 mAh g-1) and natural abundance. However, its practical implementation is hindered by severe volume expansion and interfacial instability during lithiation, which result in electrode degradation and low initial coulombic efficiency (ICE). Silicon oxide (SiOx) has emerged as a viable alternative, offering improved structural integrity and more stable cycling performance. Nevertheless, it still suffers from significant ICE loss due to irreversible lithium silicate formation and lithium trapping. Metal doping has recently gained increasing attention as an effective strategy to address these limitations. Incorporation of metal elements such as Mg, Sn, Ti, Li, into SiOx has been demonstrated to enhance electrical conductivity, stabilize both the structure and the solid electrolyte interphase (SEI), and suppress the formation of electrochemically inactive phases-leading to improved ICE and prolonged cycle life. In this review, we provide a comprehensive summary of recent advances in metal doping strategies for SiOx-based anodes. The focus is placed on doping mechanisms, synthesis methodologies, and their impact on structural and electrochemical properties, with an emphasis on practical feasibility for next-generation LIB applications.

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