SCIENCE CHINA Materials, Volume 63 , Issue 7 : 1227-1234(2020) https://doi.org/10.1007/s40843-020-1303-4

Nitrogen-doped black titania for high performance supercapacitors

More info
  • ReceivedFeb 27, 2020
  • AcceptedMar 16, 2020
  • PublishedApr 21, 2020


For energy storage system, it is still a huge challenge to achieve high energy density and high power density simultaneously. One potential solution is to fabricate electrochemical capacitors (ECs), which store electric energy through surface ion adsorption or redox reactions. Here we report a new electrode material, heavy nitrogen-doped(9.29 at.%) black titania (TiO2−x:N). This unique hybrid material, consisting of conductive amorphous shells supported on nanocrystalline cores, has rapid N-mediated redox reaction (TiO2−xNy + zH+ + ze« TiO2−xNyHz), especially in acidic solutions, providing a specific capacitance of 750 F g−1 at 2 mV s−1(707 F g−1 at 1 A g−1), great rate capability (503 F g−1 at 20 A g−1), and maintain stable after initial fading. Being a new developed supercapacitor material, nitrogen-doped black titania may revive the oxide-based supercapacitors.

Funded by

National Key Research and Development Program of China(2016YFB0901600)

the National Natural Science Foundation of China(51672301)

STC of Shanghai(16JC1401700)

U.S. Department of Energy BES grant DE-FG02-11ER46814.


This work was financially supported by the National key R&D Program of China (2016YFB0901600), and the Key Research Program of Chinese Academy of Sciences (QYZDJ-SSW-JSC013). Chen IW was supported by U.S. Department of Energy BES grant DE-FG02-11ER46814 and used the facilities (Laboratory for Research on the Structure of Matter) supported by NSF grant DMR-11-20901.

Interest statement

The authors declare that they have no conflict of interest.

Contributions statement

Yang C, Huang F, and Chen IW designed the experiment; Yang C, Wang X, Xu J, and Wang Z engineered the samples and the tests; Gu H performed the SEM and TEM tests. Yang C, Wang X, and Dong W analyzed the data. Yang C and Dong W wrote the paper with support from Huang F. All authors contributed to the general discussion.

Author information

Chongyin Yang obtained his PhD under the supervision of Prof. Fuqiang Huang at Shanghai Institute of Ceramics of the Chinese Academy of Sciences (SICCAS). He is now an assistant research scientist at the Department of Chemistry and Biochemistry, University of Maryland. His research interests include the design, synthesis and application of supercapacitors and lithium-ion batteries.

Fuqiang Huang obtained his PhD in science from Beijing Normal University in 1996. Then he joined the State Key Lab of High Performance Ceramics & Superfine Microstructure at SICCAS, and became a full professor in 2003. His research interests focus on the new energy materials and devices. He put forward the concept of multiple physical quantities synergy in structure function region for energy conversion materials and the theoretical model of accumulation factor.


Supplementary information

Supporting data are available in the online version of the paper.


[1] Miller JR, Simon P. Materials science: Electrochemical capacitors for energy management. Science, 2008, 321: 651-652 CrossRef PubMed Google Scholar

[2] Yu G, Xie X, Pan L, et al. Hybrid nanostructured materials for high-performance electrochemical capacitors. Nano Energy, 2013, 2: 213-234 CrossRef Google Scholar

[3] Lin T, Chen IW, Liu F, et al. Nitrogen-doped mesoporous carbon of extraordinary capacitance for electrochemical energy storage. Science, 2015, 350: 1508-1513 CrossRef PubMed Google Scholar

[4] Chiang YM. Building a better battery. Science, 2010, 330: 1485-1486 CrossRef PubMed Google Scholar

[5] Lu X, Yu M, Wang G, et al. H-TiO2@MnO2//H-TiO2@C core-shell nanowires for high performance and flexible asymmetric supercapacitors. Adv Mater, 2013, 25: 267-272 CrossRef PubMed Google Scholar

[6] Fan Z, Yan J, Wei T, et al. Asymmetric supercapacitors based on graphene/MnO2 and activated carbon nanofiber electrodes with high power and energy density. Adv Funct Mater, 2011, 21: 2366-2375 CrossRef Google Scholar

[7] Chen PC, Shen G, Shi Y, et al. Preparation and characterization of flexible asymmetric supercapacitors based on transition-metal-oxide nanowire/single-walled carbon nanotube hybrid thin-film electrodes. ACS Nano, 2010, 4: 4403-4411 CrossRef PubMed Google Scholar

[8] Wang DW, Li F, Liu M, et al. 3D aperiodic hierarchical porous graphitic carbon material for high-rate electrochemical capacitive energy storage. Angew Chem Int Ed, 2008, 47: 373-376 CrossRef PubMed Google Scholar

[9] Ji J, Zhang LL, Ji H, et al. Nanoporous Ni(OH)2 thin film on 3D ultrathin-graphite foam for asymmetric supercapacitor. ACS Nano, 2013, 7: 6237-6243 CrossRef PubMed Google Scholar

[10] Zhao X, Zhang L, Murali S, et al. Incorporation of manganese dioxide within ultraporous activated graphene for high-performance electrochemical capacitors. ACS Nano, 2012, 6: 5404-5412 CrossRef PubMed Google Scholar

[11] Lu Q, Lattanzi MW, Chen Y, et al. Supercapacitor electrodes with high-energy and power densities prepared from monolithic NiO/Ni nanocomposites. Angew Chem Int Ed, 2011, 50: 6847-6850 CrossRef PubMed Google Scholar

[12] Wu ZS, Wang DW, Ren W, et al. Anchoring hydrous RuO2 on graphene sheets for high-performance electrochemical capacitors. Adv Funct Mater, 2010, 20: 3595-3602 CrossRef Google Scholar

[13] Augustyn V, Come J, Lowe MA, et al. High-rate electrochemical energy storage through Li+ intercalation pseudocapacitance. Nat Mater, 2013, 12: 518-522 CrossRef PubMed Google Scholar

[14] Chmiola J, Yushin G, Gogotsi Y, et al. Anomalous increase in carbon capacitance at pore sizes less than 1 nanometer. Science, 2006, 313: 1760-1763 CrossRef PubMed Google Scholar

[15] Pech D, Brunet M, Durou H, et al. Ultrahigh-power micrometre-sized supercapacitors based on onion-like carbon. Nat Nanotech, 2010, 5: 651-654 CrossRef PubMed Google Scholar

[16] Simon P, Gogotsi Y. Materials for electrochemical capacitors. Nat Mater, 2008, 7, 845-854. Google Scholar

[17] Fujishima A, Honda K. Electrochemical photolysis of water at a semiconductor electrode. Nature, 1972, 238: 37-38 CrossRef PubMed Google Scholar

[18] Bach U, Lupo D, Comte P, et al. Solid-state dye-sensitized mesoporous TiO2 solar cells with high photon-to-electron conversion efficiencies. Nature, 1998, 395: 583-585 CrossRef Google Scholar

[19] Wang Z, Yang C, Lin T, et al. Visible-light photocatalytic, solar thermal and photoelectrochemical properties of aluminium-reduced black titania. Energy Environ Sci, 2013, 6: 3007-3014 CrossRef Google Scholar

[20] Wang Z, Yang C, Lin T, et al. H-doped black titania with very high solar absorption and excellent photocatalysis enhanced by localized surface plasmon resonance. Adv Funct Mater, 2013, 23: 5444-5450 CrossRef Google Scholar

[21] Brezesinski T, Wang J, Polleux J, et al. Templated nanocrystal-based porous TiO2 films for next-generation electrochemical capacitors. J Am Chem Soc, 2009, 131: 1802-1809 CrossRef PubMed Google Scholar

[22] Xia T, Zhang C, Oyler NA, et al. Hydrogenated TiO2 nanocrystals: A novel microwave absorbing material. Adv Mater, 2013, 25: 6905-6910 CrossRef PubMed Google Scholar

[23] Green MA, Xu J, Liu H, et al. Terahertz absorption of hydrogenated TiO2 nanoparticles. Mater Today Phys, 2018, 4: 64-69 CrossRef Google Scholar

[24] Green M, Van Tran AT, Smedley R, et al. Microwave absorption of magnesium/hydrogen-treated titanium dioxide nanoparticles. Nano Mater Sci, 2019, 1: 48-59 CrossRef Google Scholar

[25] Green M, Xiang P, Liu Z, et al. Microwave absorption of aluminum/hydrogen treated titanium dioxide nanoparticles. J Materiomics, 2019, 5: 133-146 CrossRef Google Scholar

[26] Lu X, Wang G, Zhai T, et al. Hydrogenated TiO2 nanotube arrays for supercapacitors. Nano Lett, 2012, 12: 1690-1696 CrossRef PubMed Google Scholar

[27] Lin T, Yang C, Wang Z, et al. Effective nonmetal incorporation in black titania with enhanced solar energy utilization. Energy Environ Sci, 2014, 7: 967-972 CrossRef Google Scholar

[28] Bi H, Huang F, Liang J, et al. Large-scale preparation of highly conductive three dimensional graphene and its applications in CdTe solar cells. J Mater Chem, 2011, 21: 17366-17370 CrossRef Google Scholar

[29] Gao Q, Demarconnay L, Raymundo-Piñero E, et al. Exploring the large voltage range of carbon/carbon supercapacitors in aqueous lithium sulfate electrolyte. Energy Environ Sci, 2012, 5: 9611-9617 CrossRef Google Scholar

[30] Xie Y, Fu D. Photochemical performance and electrochemical capacitance of titania nanocomplexes. Mater Res Bull, 2010, 45: 628-635 CrossRef Google Scholar

[31] Salari M, Aboutalebi SH, Konstantinov K, et al. A highly ordered titania nanotube array as a supercapacitor electrode. Phys Chem Chem Phys, 2011, 13: 5038-5041 CrossRef PubMed Google Scholar

[32] Salari M, Konstantinov K, Liu HK. Enhancement of the capacitance in TiO2 nanotubes through controlled introduction of oxygen vacancies. J Mater Chem, 2011, 21: 5128-5133 CrossRef Google Scholar

[33] Zhou H, Zhang Y. Electrochemically self-doped TiO2 nanotube arrays for supercapacitors. J Phys Chem C, 2014, 118: 5626-5636 CrossRef Google Scholar

[34] Ozkan S, Nguyen NT, Hwang I, et al. Highly conducting spaced TiO2 nanotubes enable defined conformal coating with nanocrystalline Nb2O5 and high performance supercapacitor applications. Small, 2017, 13: 1603821 CrossRef PubMed Google Scholar

[35] Heng I, Lai CW, Juan JC, et al. Low-temperature synthesis of TiO2 nanocrystals for high performance electrochemical supercapacitors. Ceramics Int, 2019, 45: 4990-5000 CrossRef Google Scholar

[36] Qorbani M, Khajehdehi O, Sabbah A, et al. Ti‐rich TiO2 tubular nanolettuces by electrochemical anodization for all‐solid‐state high‐rate supercapacitor devices. ChemSusChem, 2019, 12: 4064-4073 CrossRef PubMed Google Scholar

[37] Wang Q, Li M, Wang Z. Supercapacitive performance of TiO2 boosted by a unique porous TiO2/Ti network and activated Ti3+. RSC Adv, 2019, 9: 7811-7817 CrossRef Google Scholar

  • Figure 1

    Structure and nanostructure. (a) XRD patterns of Al-reduced titania before (TiO2−x) and after (TiO2−x:N) nitrogen doping. (b) HRTEM image. (c) HAADF-STEM image of TiO2−x:N. (d) High resolution DF-TEM image for the same region as (c). (e) HAADF-STEM image of TiO2−x:N at a lower magnification. (f) DF-TEM image for the same region as (e), with different crystallite orientations indicated by different colors according to the SAED pattern in (g).

  • Figure 2

    XPS, magnetic hysteresis and EPR spectra of TiO2, TiO2−x and TiO2−x:N. (a) N 1s and (b) O 1s core-level XPS of titania powder before (TiO2) and after Al-reduction (TiO2−x), and after further nitrogen doping (TiO2−x:N). Main peak in O 1s XPS around 529.9 eV is assigned to Ti–O bonds, and shoulder at around 532 eV is due to adsorbed hydroxyl groups. (c) Ti 2p XPS of TiO2, TiO2−x, and TiO2−x:N, and their de-convolutions. Same spectra of TiO2−x and TiO2 suggest surface oxidation of Ti3+ (and possibly some Ti2+) due to exposure to atmospheric O2 and H2O. (d) MH and (e) EPR spectra of TiO2, TiO2−x, and TiO2−x:N showing TiO2−x:N being intermediate between TiO2 and TiO2−x.

  • Figure 3

    Electrochemical performance. (a) CV curves of TiO2−x:N and TiO2−x scanned at 2 mV s−1 in 0.5 mol L−1 H2SO4 aqueous electrolyte. TiO2 shows no activity. (b) Rate capability spanning over 2 to 100 mV s−1. (c) Galvanostatic charge/discharge (CC) curves of TiO2−x:N electrode measured at 1–20 mA (1–20 A g−1). (d) Rate capability spanning over 1 to 20 A g−1 and 2–100 mV s−1. (e) Cole-Cole plot of complex impedance of TiO2−x:N electrode, with frequency marked at two locations. Inset: phase angle versus frequency. (f) Retained capacitances of TiO2−x:N in 0.5 mol L−1 H2SO4 after 2000 CV cycles at a scan rate of 100 mV s−1.

  • Figure 4

    Mechanism investigation. (a–c) The corresponding N 1s, O 1s and Ti 2p XPS spectra of electrochemically treated TiO2−x:N electrodes. Electrodes were held at 0.7 V (vs. Ag/AgCl, oxidation potential) for 48 and 96 h. (d) EPR spectra of pristine TiO2−x and TiO2−x:N electrodes. The latter was also electrochemically treated for up to 96 h. Electrodes were held at 0.7 V (vs. Ag/AgCl, oxidation potential) for 48 h and then 0 V for 48 h.

  • Table 1   Table 1 Performance comparison of the TiO2-based supercapacitors

    Electrode materials

    Specific capacitance




    750 F g−1@2 mV s−1

    707 F g−1@1 A g−1

    0.5 mol L−1 H2SO4

    This work

    TiO2 nanotube array

    TiO2 nanoribbon–nanotube

    TiO2 nanowire–nanotube

    3.113 mF cm−2@10 μA cm−2

    1.394 mF cm−2@10 μA cm−2

    0.539 mF cm−2@10 μA cm−2

    1.0 mol L−1 H2SO4


    TiO2 nanotube

    TiO2 powder

    911 μF cm−2@1 mV s−1

    181 μF cm−2@1 mV s−1

    1 mol L−1 KCl


    TiO2x nanotube

    900 μF cm−2@1 mV s−1

    1 mol L−1 KCl


    Hydrogenated TiO2 nanotube

    14.95 mF cm−2@10 mV s−1

    3.24 mF cm−2@100 mV s−1

    0.5 mol L−1 Na2SO4




    253.4 F g−1@10 mV s−1

    197.1 F g−1@10 mV s−1

    5 mol L−1 LiCl


    Nitrided TiO2 nanoparticle

    85.7 mF cm−2@10 mV s−1

    0.5 mol L−1 Na2SO4


    TiO2 nanotube

    TiO2/Nb2O5 nanotube

    Nitrided TiO2/Nb2O5 nanotube

    158 μF cm−2@1 mV s−1

    1536 μF cm−2@1 mV s−1

    37 mF cm−2@1 mV s−1

    1.0 mol L−1 H2SO4


    TiO2 nanocrystals

    146 F g−1@0.2 A g−1

    1 mol L−1 KOH


    Ti-rich TiO2

    3.8 mF cm−2@25 μA cm−2

    0.5 mol L−1 Na2SO4



    81.75 mF cm−2@2 mV s−1

    1.0 mol L−1 H2SO4


Copyright 2020 Science China Press Co., Ltd. 《中国科学》杂志社有限责任公司 版权所有

京ICP备17057255号       京公网安备11010102003388号