Lityum sülfür bataryalar için SiO2 kaplı karbon ara katmanları

Öz

Sülfürün yüksek teorik kapasite, bulunabilirlik, düşük fiyat, doğa dostu özellikleri nedeniyle Lityum-sülfür bataryaları büyük ilgi çekmektedir. Ancak, düşük elektrokimyasal performans Li-sülfür bataryaların elektrokimyasal performansını kısıtlamaktadır. Ayırıcı ile katod arasına gözenekli elektriksel iletkenliği yüksek ara katman yerleştirilmesi aktif malzeme kullanımını arttırır ve polisülfid transferini kısıtlar böylece elektrokimasal özellikleri iyileştirir. SiO2 polar yapısı ve polisülfid ile güçlü elektrokimyasal etkileşimi ile elektrokimyasal performansı iyileştirir. SiO2 kaplı yüksek iletkenliğe sahip karbon nanolifler lityum sulfur bataryalarda arakatman olarak kullanıldı. Karbon nanolifler üzerindeki SiO2 kaplama SEM ve TEM ile görüntülendi. SiO2@CNF arakatmanlarla hazırlanan bataryalar yüksek spesifik kapasite gösterdi,1547 mAh/g, ve 200 deşarj-şarj sonunda 916 mAh/g kapasite elde edildi. Yüksek elektrokimyasal performans SiO2 nanoparçacıklarının yüksek yüzey alanı ve karbon nanoliflerin iletkenliği ie açıklanabilir.

Anahtar Kelimeler

• SiO2 nanoparticles, electrospinning
• ,batteries,
• Li-S,

SiO2 coated carbon interlayer for Li-S batteries

Öz

Lithium-sulfur batteries have received great attention because of the high theoretical specific capacity, natural abundance, low cost, and environmental friendliness of sulfur. However, poor cycling and C-rate performance limit the application of Li-sulfur batteries. Placing porous and highly conductive interlayer between separators and sulfur cathodes is an efficient approach to improve active materials’ utilization and limit the polysulfide shuttle effect and thus enhance the electrochemical properties of Li-sulfur cells. Moreover, SiO2 could further improve electrochemical performance via capturing large amount of polysulfides owing to the polar structure and strong chemical interactions. SiO2 coated highly conductive carbon nanofibers were prepared and used as an interlayer in Li-sulfur batteries. The uniform coating of SiO2 nanoparticles on carbon nanofibers were observed from SEM and TEM images. The cells with SiO2 nanoparticles coated highly conductive carbon nanofiber (SiO2@CNF) interlayers delivered high first discharge capacity of 1547 mAh/g and retained the specific capacity of around 916 mAh/g in 200 cycles at 0.2C. The cells with SiO2@CNF interlayers also showed improved C-rate performance compared the cells without SiO2@CNF interlayers. The enhanced electrochemical performance resulted not only from high polysulfides capturing ability of SiO2 nanoparticles with high specific surface area but also highly conductive interconnected structure of carbon nanofibers. Highly porous structure of SiO2@CNF led to large amount of polysulfide adsorption and highly conductive structure resulted in reutilization of adsorbed polysulfides and thereby improved reversible specific capacities.

Anahtar Kelimeler

• sio2
• electrospinning
• Li-S

Kaynakça

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