S-Space College of Engineering/Engineering Practice School (공과대학/대학원) Dept. of Materials Science and Engineering (재료공학부) Journal Papers (저널논문_재료공학부)
Enhancing the cycle stability of Li-O-2 batteries via functionalized carbon nanotube-based electrodes
- Cho, Young Shik; Kim, Hyunjin; Byeon, Minhoo; Kim, Dong Young; Park, Hyeokjun; Jung, Yeonsu; Bae, Youngjun; Kim, Mokwon; Lee, DongJoon; Park, JungOck; Kang, Kisuk; Im, Dongmin; Park, Chong Rae
- Issue Date
- Journal of Materials Chemistry A, Vol.8 No.8, pp.4263-4273
- Achieving the high theoretical energy density (similar to 3500 W h kg(-1)) of Li-O-2 batteries involves maximizing the electrochemically active surface area (EASA) of the electrodes. Carbon nanotubes (CNTs) have been widely adopted for Li-O-2 electrodes but their EASA is limited by their electrolyte-phobic surface nature and the strong van der Waals interaction between CNTs. To increase the affinity between CNT-based electrodes and the electrolyte without decreasing CNT chemical stability, CNT buckypapers are functionalized with 3,5-bis(trifluoromethyl)phenylmaleimide. The solubility parameters of the electrolyte and CNTs are considered so that the maleimide groups increase the affinity between the electrode and electrolyte and the 3,5-bis(trifluoromethyl)phenyl groups protect the maleimide groups from decomposition. The functionalized CNT cathode exhibits a 58% greater discharge capacity and a 50% increased cyclability compared to the pristine CNT cathode when a 1 : 2.5 weight ratio of CNT to electrolyte was used due to an increased EASA and steric hindrance effect. Finally, a 3D folded Li-O-2 cell is fabricated using the functionalized CNT-based cathode and demonstrated 30 cycles at 100 W h kg(cell)(-1) cutoff. These results clearly show that high energy density and long cycling performance of Li-O-2 batteries can be achieved even with a much reduced amount of electrolyte by increasing the affinity between CNT-based electrodes and the electrolyte.
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