Nitridation-boosted V eg occupation of a VN@CNT flexible electrode for high-rate Zn-ion hybrid supercapacitors

Abstract

Flexible zinc-ion hybrid supercapacitors (f-ZHSCs), with their inherent safety, combine the advantages of the high power density of supercapacitors and the high energy density of zinc-ion batteries, making them a promising energy supply device for wearable and implantable devices. However, commonly used rigid cathode materials and fracture-prone metallic current collectors encounter significant challenges, such as inadequate flexibility and compromised cycling stability, which impede the further development of f-ZHSCs. Herein, we design a free-standing flexible membrane electrode VN@CNT for f-ZHSCs through a nitridation strategy. Soft X-ray absorption spectroscopy (s-XAS) reveals the boosted occupation of electrons in the V eg orbital 3dx2y2 state after nitridation, leading to enhanced metallicity and conductivity. As a result, the VN@CNT flexible electrode exhibits an excellent specific capacitance of 314.44 F g−1 at 0.5 A g−1. Moreover, it demonstrates exceptional rate capability, retaining 80.17% of its capacitance at a high current density of 10 A g−1 compared to that of 0.5 A g−1. Importantly, it also shows excellent flexibility, enduring bending angles of 0 to 180° and showing no detectable degradation in capacitance after 1200 bending cycles. By design and in-depth study of the local structure of the flexible electrode, this work provides insight into the development of flexible electronics.

Graphical abstract: Nitridation-boosted V eg occupation of a VN@CNT flexible electrode for high-rate Zn-ion hybrid supercapacitors

Supplementary files

Article information

Article type
Paper
Submitted
29 Mar 2024
Accepted
13 Jun 2024
First published
14 Jun 2024

J. Mater. Chem. A, 2024, Advance Article

Nitridation-boosted V eg occupation of a VN@CNT flexible electrode for high-rate Zn-ion hybrid supercapacitors

Y. Cao, S. Wei, Y. Xia, Q. Zhou, Y. Wang, W. Xu, C. Wang, S. Chen and L. Song, J. Mater. Chem. A, 2024, Advance Article , DOI: 10.1039/D4TA02102A

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