High performance Li-ion capacitor based on novel carbon-coated chalcogenide anode

Abstract

Lithium-ion capacitors (LICs) exhibit the combined advantages of lithium-ion batteries and supercapacitors. Till now, the development of efficient LICs with high energy-power densities with high cyclic stability is restricted due to the limited performance of the electrode in terms of low capacity and sluggish reaction kinetics. Developing a novel electrode that overcomes these existing drawbacks is one of the possible strategies to enhance electrochemical performance. In this work, the superior Li-ion storage capability of highly interconnected Cu2SnS3 (CSS) nanospheres encapsulated in the carbon nanotubes (CNTs) framework as an efficient anode for LIC is demonstrated. Benefiting from the combined charge storage mechanisms of the CSS (alloying + conversion) and the CNTs (insertion), an exceptional high electrochemical performance in terms of high energy density (158.77 Wh/kg) and high power density (12,500 W/kg) with superior cyclic stability for 10,000 cycles is obtained from the fabricated LIC device. The key factors attributed to the improved electrochemical performance are studied in detail using experimental results, comprehensive characterization techniques and are strongly supported by the relevant simulated models based on theoretical calculations. The plausible binding characteristics of the Li-ion and the valence charge transfer in the electrodes are evaluated using first-principle density functional theory (DFT).