S-Space College of Engineering/Engineering Practice School (공과대학/대학원) Dept. of Material Science and Engineering (재료공학부) Journal Papers (저널논문_재료공학부)
Facile synthesis of Nb2O5@Carbon core-shell nanocrystals with controlled crystalline structure for high-power anodes in hybrid supercapacitors
- Lim, Eunho; Jo, Changshin; Kim, Haegyeom; Kim, Mok-Hwa; Mun, Yeongdong; Chun, Jinyoung; Ye, Youngjin; Hwang, Jongkook; Ha, Kyoung-Su; Roh, Kwang Chul; Kang, Kisuk; Yoon, Songhun; Lee, Jinwoo
- Issue Date
- ACS Nano, Vol.9 No.7, pp.7497-7505
- orthorhombic Nb2O5 nanocrystals; controlled crystal structures; core-shell nanostructures; high-power anodes; hybrid supercapacitors
- Hybrid supercapacitors (battery-supercapacitor hybrid devices, HSCs) deliver high energy within seconds (excellent rate capability) with stable cyclability. One of the key limitations in developing high-performance HSCs is imbalance in power capability between the sluggish Faradaic lithium-intercalation anode and rapid non-Faradaic capacitive cathode. To solve this problem, we synthesize Nb2O5@carbon core-shell nanocyrstals (Nb2O5@C NCs) as high-power anode materials with controlled crystalline phases (orthorhombic (7) and pseudohexagonal (TT)) via a facile one-pot synthesis method based on a water-in-oil microemulsion system. The synthesis of ideal T-Nb2O5 for fast Li+ diffusion is simply achieved by controlling the microemulsion parameter (e.g., pH control). The T-Nb2O5@C NCs shows a reversible specific capacity of similar to 180 mA h g(-1) at 0.05 A g(-1) (1.1-3.0 V vs Li/Li+) with rapid rate capability compared to that of TT-Nb2O5@C and carbon shell-free Nb2O5 NCs, mainly due to synergistic effects of (i) the structural merit of T-Nb2O5 and (ii) the conductive carbon shell for high electron mobility. The highest energy (similar to 63 W h kg(-1)) and power (16 528 W kg(-1) achieved at similar to 5 W h kg(-1)) densities within the voltage range of 1.0-35 V of the HSC using T-Nb2O5@C anode and MSP-20 cathode are remarkable.
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