A flexible zinc ion hybrid capacitor integrated system with layers-dependent V2CTx MXene

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Switzerland : 1996), 2023-02, Vol.454, p.140360, Article 140360
• Main Authors: Zhao, Sairao, Luo, Xiao, Cheng, Yongfa, Shi, Zhixiang, Huang, Tao, Yang, Shanghua, Zheng, Haojian, Bi, Yun, Zhang, Jun, Shi, Qiuyue, Cao, Minglei, Zhang, Chuankun, Yue, Yang, Ma, Yanan
• Format: Article
• Language: English
• Subjects: Anti-self-discharge; Electrophoretic deposition; V2CTx; Zinc ion hybrid capacitor
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2022.140360

•V2CTx with controllable layers was obtained by etching and intercalation technique.•The flexible V2CTx electrodes were prepared by the electrophoretic approach.•The F-ZIHC exhibits outstanding areal capacity and cycling stability.•The F-ZIHC exhibits excellent anti-self-discharge resistance of 6.4 mV h−1.•This work can broaden the applications in wearable fields and integrated systems. Ti3C2Tx MXene with unique physical and chemical properties are recently sparked tremendous interest in the energy storage field. Compared to Ti3C2Tx, V2CTx MXene is a more promising candidate for energy storage due to a low number of atomic layers in the V2CTx structure and varied valence states of vanadium. Herein, we report a flexible V2CTx electrode with different layers (named accordion-like V2CTx, multi-layer V2CTx, and few-layer V2CTx, respectively) fabricated by using electrophoretic deposition, then assembled a flexible zinc ion hybrid capacitor (ZIHC) by virtue of zinc anode and gel electrolyte. The areal capacitance of few-layer V2CTx based ZIHC is 54.12 mF cm−2 at 0.1 mA cm−2, which is greater than those of accordion-like V2CTx and multi-layer V2CTx based ZIHC. The outstanding electrochemical performance of few-layer V2CTx based ZIHC is attributed to its richer active sites and shorter ion transport routes. Additionally, the few-layer V2CTx based ZIHC also owns well cycling stability, with 81.48 % capacity retention after 8000 cycles, and a low self-discharge rate of 6.4 mV h−1, making it suitable for wearable devices. So, the V2CTx based ZIHC is integrated with a Ti3C2Tx based pressure sensor to monitor diverse human activities, demonstrating its steady and long-term power supply capacity as the energy storage device.