Ultrahigh-energy sodium ion capacitors enabled by the enhanced intercalation pseudocapacitance of self-standing Ti2Nb2O9/CNF anodes

Liaona She; Feng Zhang; Congying Jia; Liping Kang; Qi Li; Xuexia He; Jie Sun; Zhibin Lei; Zong-Huai Liu

doi:10.1039/d1nr04241f

Ultrahigh-energy sodium ion capacitors enabled by the enhanced intercalation pseudocapacitance of self-standing Ti₂Nb₂O₉/CNF anodes

Nanoscale. 2021 Oct 1;13(37):15781-15788. doi: 10.1039/d1nr04241f.

Authors

Liaona She^{1

2

3

4}, Feng Zhang^{1

2

3}, Congying Jia^{1

2

3}, Liping Kang^{1

2

3}, Qi Li^{1

2

3}, Xuexia He^{1

2

3}, Jie Sun^{1

2

3}, Zhibin Lei^{1

2

3}, Zong-Huai Liu^{1

2

3}

Affiliations

¹ Key Laboratory of Applied Surface and Colloid Chemistry (Shaanxi Normal University), Ministry of Education, Xi'an, 710062, P. R. China.
² Shaanxi Key Laboratory for Advanced Energy Devices, Xi'an, 710119, P. R. China.
³ School of Materials Science and Engineering, Shaanxi Normal University, Xi'an, 710119, P. R. China. zhliu@snnu.edu.cn.
⁴ Institute of Science and Technology for New Energy, Xi'an Technological University, Xi'an, 710021, P. R. China.

PMID: 34528656
DOI: 10.1039/d1nr04241f

Abstract

In order to increase the capacity and improve the sluggish Na⁺-reaction kinetics of anodes as sodium ion capacitors (SICs), a Ti₂Nb₂O₉/CNF self-standing film electrode comprised of Ti₂Nb₂O₉ nanosheets and carbon nanofibers has been fabricated via electrospinning HTiNbO₅ nanosheets with PAN and subsequent carbonization treatment. The as-prepared Ti₂Nb₂O₉/CNF film electrode possesses fast Na-ion intercalation kinetics and high conductivity during Na-ion storage, and it displays a high reversible capacity of 324 mA h g^-1 at 0.1 A g^-1. Additionally, it also delivers a superior rate capability of 204 mA h g^-1 at a high current density of 4 A g^-1, as well as an excellent cycling stability of 97% retention after 2000 cycles at 1 A g^-1 in a half-cell test. A prototype Ti₂Nb₂O₉/CNF//AC SIC full device was assembled by employing the presodiated Ti₂Nb₂O₉/CNF anode and AC cathode, and it exhibits an high energy density of 129 W h kg^-1 at a power density of 75 W kg^-1 and a high power density (7560 W kg^-1 with 63 W h kg^-1), a good cycling performance of 85% capacitance retention after 10 000 cycles at 1 A g^-1, suggesting that the Ti₂Nb₂O₉/CNF electrode with excellent performance would be a very promising candidate as the anode for high-performance SICs.