PANI-Coated VO[sub.x] Nanobelts with Core-Shell Architecture for Flexible All-Solid-State Supercapacitor

• Published in: Micromachines (Basel) Vol. 14; no. 10
• Main Authors: Zhang, Qiang, Li, Xianran, Zheng, Yinyin, Tu, Qian, Wei, Shiwen, Shi, Hong, Tang, Wentao, Chen, Liangzhe
• Format: Journal Article
• Language: English
• Published: MDPI AG 01.09.2023
• Subjects: Capacitors; China
• ISSN: 2072-666X; 2072-666X
• DOI: 10.3390/mi14101856

As a typical pseudocapacitor material, VO[sub.x] possesses mixed valence states, making it an ideal electrode material for symmetric screen-printed supercapacitors. However, its high internal resistance and low energy density are the main hurdles to its widespread application. In this study, a two-dimensional PANI@VO[sub.x] nanobelt with a core-shell architecture was constructed via a two-step route. This strategy involves the preparation of VO[sub.x] using a solvothermal method, and a subsequent in situ polymerization process of the PANI. By virtue of the synergistic effect between the VO[sub.x] core and the PANI shell, the optimal VO[sub.x]@PANI has an enhanced conductivity of 0.7 ± 0.04 S/Ω, which can deliver a high specific capacitance of 347.5 F/g at 0.5 A/g, a decent cycling life of ~72.0%, and an outstanding Coulomb efficiency of ~100% after 5000 cycles at 5 A/g. Moreover, a flexible all-solid-state symmetric supercapacitor (VO[sub.x]@PANI SSC) with an in-planar interdigitated structure was screen-printed and assembled on a nickel current collector; it yielded a remarkable areal energy density of 115.17 μWh/cm[sup.2] at an areal power density of 0.39 mW/cm[sup.2], and possessed outstanding flexibility and mechanical performance. Notably, a “Xiaomi” hygrothermograph (3.0 V) was powered easily by tandem SSCs with an operating voltage of 3.1 V. Therefore, this advanced pseudocapacitor material with core-shell architecture opens novel ideas for flexible symmetric supercapacitors in powering portable/wearable products.