Ultra-Lightweight and Flexible Current Collector Based on Freestanding Carbon Nanotube Sheets for Lithium-Ion Capacitors

초록

A new and simple strategy for the fabrication of an ultra-lightweight and flexible current collector based on freestanding carbon nanotube (CNT) sheets for lithium-ion capacitors (LICs) with excellent electrochemical performance is reported. A novel lightweight current collector is fabricated using CNT sheets (?0.05 mg cm?2) which are prepared by a direct spinning method. LICs are assembled using prelithiated graphite/CNT sheets as anodes, and activated carbon/CNT sheets as cathodes. The electrochemical performances of anode and cathode are investigated through coin-type half-cell tests, demonstrating the high discharge capacities of about 350 and 40 mAh g?1, respectively. These discharge capacities based on the total mass of electrode exhibit about 73% and 75% of capacities based on the mass of active materials. However, in the case of fabricating metallic current collector electrode, discharge capacities are reduced to about 6.5% and 20%, respectively. LICs demonstrate the maximum energy density of ?26.4 Wh kg?1 and the maximum power density of ?672 W kg?1, showing comparable energy and power densities when values are evaluated on the basis of the total mass of electrode. These features make the collector a potential candidate for the energy storage systems, which require large-scale and lightweight power sources. ? 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

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