Graphene paper with controlled pore structure for high-performance cathodes in Li-O₂ batteries

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• 作者：Do Youb Kim^a ; Mokwon Kim^b ; ¹ ; Dong Wook Kim^a ; Jungdon Suk^a ; Jung Jin Park^b ; O Ok Park^b ; Yongku Kang^a ; ^{ykang@krict.re.kr" class="auth_mail" title="E-mail the corresponding author}
• 刊名：Carbon
• 出版年：2016
• 出版时间：April 2016
• 年：2016
• 卷：100
• 期：Complete
• 页码：265-272
• 全文大小：2044 K

文摘

In non-aqueous Li–O₂ batteries, relatively large amounts of discharge products are formed on air cathodes. As such, the expansion of air cathodes is a critical issue that remains to be solved. Here, we report the fabrication of highly porous free-standing graphene paper by introducing macropores within the paper using polystyrene colloidal particles as a sacrificial template. The as-prepared macroporous graphene paper (mp-GP) have a large Brunauer–Emmett–Teller (BET) surface area (ca. 373 m² g⁻¹), a large pore volume (ca. 10.9 cm³ g⁻¹), and a high porosity (91.6%). Owing to the high surface area and large pore volume, the mp-GPs exhibit a high specific capacity of ca. 12,200 mAh g⁻¹ at a current density of 200 mA g⁻¹, as well as good rate capability, when used as an air cathode in a non-aqueous Li–O₂ battery. Moreover, the mp-GP shows good stability up to 100 and 78 cycles at a current density of 500 mA g⁻¹ and 2000 mA g⁻¹ respectively, with a limiting capacity of 1000 mAh g⁻¹. It is found that formation and decomposition of the discharge product, Li₂O₂, occur within the macropores, and thus, the mp-GP maintains its original structure without considerable expansion during cycling.