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

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...

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Bibliographic Details
Published in:Journal of materials chemistry. A, Materials for energy and sustainability Materials for energy and sustainability, 2024-06, Vol.12 (47), p.32895-32903
Main Authors: Cao, Yuyang, Wei, Shiqiang, Xia, Yujian, Zhou, Quan, Wang, Yixiu, Xu, Wenjie, Wang, Changda, Chen, Shuangming, Li, Song
Format: Article
Language:English
Subjects:
Absorption spectroscopy
Bending
Capacitance
Electrode materials
Electrodes
Flexibility
Flexible components
Metallicity
Soft x rays
Supercapacitors
X ray absorption
X-ray absorption spectroscopy
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Summary: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 3dx2−y2 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.
ISSN:2050-7488
2050-7496
DOI:10.1039/d4ta02102a