SCIENCE CHINA Materials, Volume 61 , Issue 12 : 1517-1526(2018) https://doi.org/10.1007/s40843-018-9290-y

The way to improve the energy density of supercapacitors: Progress and perspective

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  • ReceivedFeb 5, 2018
  • AcceptedApr 27, 2018
  • PublishedJun 27, 2018


Compared with other energy storage devices, supercapacitors have superior qualities, including a long cycling life, fast charge/discharge processes, and a high safety rating. The practical use of supercapacitor devices is hindered by their low energy density. Here, we briefly review the factors that influence the energy density of supercapacitors. Furthermore, possible pathways for enhancing the energy density via improving capacitance and working voltage are discussed. In particular, we offer our perspective on the most exciting developments regarding high-energy-density supercapacitors, with an emphasis on future trends. We conclude by discussing the various types of supercapacitors and highlight crucial tasks for achieving a high energy density.

Funded by

the National Natural Science Foundation of China(21371023)


This work was financially supported by the National Natural Science Foundation of China (21371023).

Interest statement

The authors declare no competing interests.

Contributions statement

Both authors participate in the manuscript preparation and general discussions.

Author information

Chuanbao Cao is currently the chief responsible professor of the School of Materials Science and Engineering, Director of Research Center of Materials Science of Beijing Institute of Technology (BIT), China. His research is focused on the electrochemical energy storage and conversion including electrode materials of super-capacitors, lithium ion battery, and photo-electrochemical materials. Until now, he has published more than 300 peer-reviewed research papers, holds or has filed 50 patents and patent applications.


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  • Figure 1

    Schematic illustration of future supercapacitors device for EVs.

  • Figure 2

    Schematic illustration of various routes to increase energy density of supercapacitor.

  • Table 1   Comparison of performances of supercapacitor and battery





    Physical or chemical





    Charge time

    Short (seconds-level)

    Long (hours-level)

    Cycling life

    Long (>105 cycles)

    Limited (~103 cycles)


    High (>104 W kg−1)

    Low (~103 W kg−1)


    Limited (<10 W h kg−1)

    High (~200 W h kg−1)

  • Table 2   Typical examples of reported EDLCs performances




    (m2 g−1)


    (F g−1)



    Energy density

    Based on


    Carbon nanospheres








    N-doped carbon nanofiber





    7.11 W h kg−1



    N-doped 3D graphene





    15.2 W h kg−1



    Functionalized 3D carbon








    Mesoporous carbon













    39.5 W h kg−1

    63 W h kg−1

    41 W h kg−1

    Active material

    Active material



    N-rich carbon-graphene





    33.89 W h kg−1



    N-rich nanocarbon








    Activation of Graphene





    70 W h kg−1

    20 W h kg−1

    Active material



    Porous carbon nanosheets





    30 W h kg−1



    Holely graphene





    127 W h kg−1

    Active material


    Hierarchical carbon





    89 W h kg−1

    Active material


    3D porous networks





    38 W h kg−1

    Active material


    Functionalized 3D carbon








    Porous carbon





    42 W h kg−1

    Active material


    Carbon flake





    45.33 W h kg−1



    Microporous carbon





    56 W h kg−1

    Active material


    Carbon nanosheets





    19 W h kg−1



    Activated graphene





    74 W h kg−1



    N-doped porous carbon





    102 W h kg−1

    Active material


    3D porous carbon





    70 W h kg−1

    Active material


    Porous carbon nanosheet





    104 W h kg−1

    Active material


    Porous carbon flake





    103 W h kg−1

    Active material


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