ORALS

Single-Walled Carbon Nanohorns (SWCNHs), are a kind of carbon material with graphene type surface structure characterized by horn shaped graphitic tubules (2-5 nm diameter and 40-50 nm tube length) to form dahlia-like structures. They can be mass produced (tons/year) using a novel proprietary process technology, making them attractive for various industrial applications. SWCNHs can be considered as the next generation of graphene-based materials. Thanks to their particular 3D structure, they do not stack as in the case of 2D graphene-based materials, and keep their original chemical-physical proprieties at the powder state. Inspired by their unique structure, Nitrogen doped Single-Walled Carbon Nanohorns (N-SWCNHs) were used as a conductive substrate with various post lithium ion batteries active materials such as Sulfur (cathode), Germanium, and Tin (anodes). The choice of nitrogen doping is motivated by the quest for improved interaction between SWCNHs and the surrounding active material. N-SWCNHs were used as porous conductive host for encapsulating sulfur, using a simple melt diffusion method. Electrochemical results obtained from N-SWCNHs-Sulfur composite as cathode for lithium sulfur batteries showed high gravimetric capacities of 1650 mAh/g (almost the theoretical capacity), with high sulfur content of 80% by weight. Furthermore, N-SWCNHs were exploited by growing 5-10 nm germanium nanocrystal around the cones of N-SWCNHs. The Ge@N-SWCNHs composite, when used as anode material, provided extremely stable and high gravimetric capacities of 1400 mAh/g at 0.1C after 100 cycles. Similarly, results were obtained for Sn@N-SWCNHs composites, where a strong reducing agent (Lithium Naphthalenide) was used to decorate Sn nanocrystal on the surface of N-SWCNHs. Capacities as high as 735 mAh/g were achieved at 0.1C even after 140 cycles. The detailed results will be presented and discussed at the symposium.

References:
[1] Nitrogen-Doped Single-Walled Carbon Nanohorns as a Cost-Effective Carbon Host toward High-Performance Lithium-Sulfur Batteries. C.Capiglia et. al., ACS Appl. Mater. Interfaces 2018, 10, 5551-5559.