Recently, hollow carbon spheres (HCS) have aroused great interests in the field of energy storage and conversion owing to their unique morphology, structure and other charming properties. Nevertheless, unsatisfactory electrical conductivity and relatively poor volumetric energy density caused by inevitable gaps between discrete carbon spheres greatly impede the practical application of HCS. In this work, for the first time we propose a novel dual-template strategy and successfully fabricate interconnected 3D hollow N-doped carbon network (HNCN) by a facile and scalable pyrolysis process. By systematical characterization and analysis, it can be found that HNCN is assembled by HCS and lots of mesoporous carbon. Compared to the counterparts, the obtained HNCN exhibits unique 3D interconnected architecture, larger specific surface area, hierarchical meso/macropore structure, higher structure defects, higher N doping amount and more optimized N configurations (especially for pyridinic-N and graphitic-N). As a result, these advantageous features endow HNCN with remarkably promoted electrochemical performance for supercapacitor and oxygen reduction reaction. Clearly, our proposed dual-template strategy provides a good guidance on overcoming the intrinsic shortcomings of HCS, which undoubtedly broadens their application in energy storage and conversion.

    Abstract
    1 Introduction
    2 Experimental
        2.1 Chemicals and materials
        2.2 Synthesis of 3D HNCN
    3 Results and discussion
        3.1 Materials characterization
        3.2 Electrochemical performance
    4 Conclusion
    References

• Liang Chen(Key Laboratory of Hunan Province for Advanced Carbon‒based Functional Materials, School of Chemistry and Chemical Engineering, Hunan Institute of Science and Technology)
• Lanyun Yang(Key Laboratory of Hunan Province for Advanced Carbon‒based Functional Materials, School of Chemistry and Chemical Engineering, Hunan Institute of Science and Technology)
• Chenxi Xu(College of Chemistry and Chemical Engineering, Hunan University)
• Kechun Chen(Key Laboratory of Jiangxi Province for Persistent Pollutants Control and Resources Recycle, Nanchang Hangkong University)
• Wei Wang(Key Laboratory of Hunan Province for Advanced Carbon‒based Functional Materials, School of Chemistry and Chemical Engineering, Hunan Institute of Science and Technology)
• Liming Yang(Key Laboratory of Jiangxi Province for Persistent Pollutants Control and Resources Recycle, Nanchang Hangkong University)
• Zhaohui Hou(Key Laboratory of Hunan Province for Advanced Carbon‒based Functional Materials, School of Chemistry and Chemical Engineering, Hunan Institute of Science and Technology)