Nitrogen and sulfur dual-doped carbon films as flexible free-standing anodes for Li-ion and Na-ion batteries

By Ruan, Jiafeng; Yuan, Tao; Pang, Yuepeng; Luo, Sainan; Peng, Chengxin; Yang, Junhe; Zheng, Shiyou
Published in Carbon 2018

Abstract

Heteroatom doping is considered to be one of the most effective approaches to improve the electrochemical activity of carbon-based electrode materials for both Li-ion batteries (LIBs) and Na-ion batteries (SIBs) due to introduction of unbalanced electron atmosphere and enlarged interlayers of carbon materials. Here, we present nitrogen and sulfur dual-doped flexible carbon (NSC) film as a promising free-standing anode for stable high-power and high-energy {LIBs} or SIBs. The {NSC} film delivers high reversible capacities of 965.7 mAh g?1 in {LIBs} and 520.1 mAh g?1 in {SIBs} at a current density of 100 mA g?1. Particularly, the film electrodes exhibit excellent high-rate capability and remarkable long-term cyclability. For instance, as a {LIBs} anode, the {NSC} film remained a high capacity of 357.2 mAh g?1 at 2.0 A g?1 (?10 min to full charge) after 2000 cycles; even in SIBs, a capacity of 155 mAh g?1 can also be reached at 1.0 A g?1. It is believed that the interconnected conducting structure of carbon backbones, heteroatomic defects and increased carbon interlayers distance by stable {SC} and {NC} bonds are beneficial to ultrafast ion diffusion and electron transport, making the {NSC} film become a high performance free-standing anode for {LIBs} or {SIBs} application.

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