N-doping content and configurations have a significant effect on the electrochemical performance of carbon anodes. Herein, we proposed a simple method to synthesize highly N self-doped chitosan-derived carbon with controllable N-doping types by introducing 2ZnCO3 ·3Zn(OH)2 into the precursor. The as-synthesized NC-CS/2ZnCO3·3Zn(OH)2 electrode exhibited more than twice the reversible capacity (518 mAh g− 1 after 100 cycles at 200 mA g− 1) compared to the NC-CS electrode, superior rate performance and outstanding cycling stability. The remarkable improvement should be mainly attributed to the increase of N-doping content (particularly the pyrrolic-N content), which provided more active sites and favored Li+ diffusion kinetics. This study develops a cost-effective and facile synthesis route to fabricate high-performance N self-doped carbon with tunable doping sites for rechargeable battery applications.

Facile and controllable synthesis of nitrogen self-doped chitosan-derived carbon for high-performance Li-ion batteries
    Abstract
        Graphical abstract
    1 Introduction
    2 Experimental
        2.1 Materials
        2.2 Preparation of NC
        2.3 Characterization
        2.4 Electrochemical measurements
    3 Results and discussion
    4 Conclusions
    Acknowledgements 
    References

• Wentao Xia(Suzhou Key Laboratory for Nanophotonic and Nanoelectronic Materials and Its Devices, School of Materials Science and Engineering, Suzhou University of Science and Technology, Suzhou 215009, Jiangsu Province, China)
• Miao Cheng(Suzhou Key Laboratory for Nanophotonic and Nanoelectronic Materials and Its Devices, School of Materials Science and Engineering, Suzhou University of Science and Technology, Suzhou 215009, Jiangsu Province, China) Corresponding author
• Jing Hu(Suzhou Key Laboratory for Nanophotonic and Nanoelectronic Materials and Its Devices, School of Materials Science and Engineering, Suzhou University of Science and Technology, Suzhou 215009, Jiangsu Province, China)
• Qianqian Liu(Suzhou Key Laboratory for Nanophotonic and Nanoelectronic Materials and Its Devices, School of Materials Science and Engineering, Suzhou University of Science and Technology, Suzhou 215009, Jiangsu Province, China)
• Tao Wei(Suzhou Key Laboratory for Nanophotonic and Nanoelectronic Materials and Its Devices, School of Materials Science and Engineering, Suzhou University of Science and Technology, Suzhou 215009, Jiangsu Province, China)
• Ruirui Wang(Suzhou Key Laboratory for Nanophotonic and Nanoelectronic Materials and Its Devices, School of Materials Science and Engineering, Suzhou University of Science and Technology, Suzhou 215009, Jiangsu Province, China)
• Wanfei Li(Suzhou Key Laboratory for Nanophotonic and Nanoelectronic Materials and Its Devices, School of Materials Science and Engineering, Suzhou University of Science and Technology, Suzhou 215009, Jiangsu Province, China)
• Bo Liu(Suzhou Key Laboratory for Nanophotonic and Nanoelectronic Materials and Its Devices, School of Materials Science and Engineering, Suzhou University of Science and Technology, Suzhou 215009, Jiangsu Province, China)