Fast-chargeable N-doped multi-oriented graphitic carbon as a Li-intercalation compound

초록

Graphite, the only commercially available anode material for lithium-ion batteries, has limitations owing to its low specific capacity and poor rate performance. Despite the immense efforts to explore various nanostructured carbon materials, most suffer from a high (de)lithiation potential and poor initial Coulombic efficiency (ICE). Herein, we design a nitrogen-doped graphitic nanoshell (N-GNS) to possess vital properties for advanced anode materials. The multi-oriented graphitic domain exposes the edge area between the discontinuous graphitic layers to improve accessibility for Li+. The interlayer spacing is enlarged, while maintaining high crystallinity, facilitating Li+ intercalation into the graphite galleries. Simultaneously, the nitrogen surface functionalities provide energetically favorable sites for Li+, enabling reversible surface capacitive storage. Consequently, the resulting material exhibits outstanding rate performance (294.6 mAh g(-1) at 5 A g(-1)) and cycling stability (372.8 mAh g(-1) after 700 cycles at 1 A g(- 1)). To elucidate the notable performance, the lithium storage mechanism is identified comprehensively by in-situ Raman analysis. Furthermore, chemical prelithiation highlights its practicability by overcoming the low ICE.

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