Coupling W18O49/Ti3C2Tx MXene Pseudocapacitive Electrodes with Redox Electrolytes to Construct High‐Performance Asymmetric Supercapacitors. Issue 52 (7th November 2022)

• Record Type: Journal Article
• Authors: Liu, Shuang; Zeng, Ting; Zhang, Yuanyuan; Wan, Qijin; Yang, Nianjun
• Is Part Of: Small. Volume 18:Issue 52(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-11-07
• Subjects: asymmetric supercapacitors -- pseudocapacitive electrodes -- redox electrolytes -- Ti 3C 2Tx MXene -- W 18O 49; Nanotechnology -- Periodicals; Nanoparticles -- Periodicals; Microtechnology -- Periodicals; 620.5
• DOI: 10.1002/smll.202204829
• Languages: English
• ISSNs: 1613-6810

Abstract

Abstract: A pseudocapacitive electrode with a large surface area is critical for the construction of a high‐performance supercapacitor. A 3D and interconnected network composed of W18 O49 nanoflowers and Ti3 C2 T x MXene nanosheets is thus synthesized using an electrostatic attraction strategy. This composite effectively prevents the restacking of Ti3 C2 T x MXene nanosheets and meanwhile sufficiently exposes electrochemically active sites of W18 O49 nanoflowers. Namely, this self‐assembled composite owns abundant oxygen vacancies from W18 O49 nanoflowers and enough active sites from Ti3 C2 T x MXene nanosheets. As a pseudocapacitive electrode, it shows a big specific capacitance, superior rate capability and good cycle stability. A quasi‐solid‐state asymmetric supercapacitor (ASC) is then fabricated using this pseudocapacitive anode and the cathode of activated carbon coupled with a redox electrolyte of FeBr3 . This ASC displays a cell voltage of 1.8 V, a capacitance of 101 F g −1 at a current density of 1 A g −1, a maximum energy density of 45.4 Wh kg −1 at a power density of 900 W kg −1, and a maximum power density of 18 000 W kg −1 at an energy density of 10.8 Wh kg −1 . The proposed strategies are promising to synthesize different pseudocapacitive electrodes as well as to fabricate high‐performance supercapacitor devices. Abstract : The W18 O49 /Ti3 C2 T x MXene composites have been prepared from two pseudocapacitive materials: Ti3 C2 T x MXene nanosheets and W18 O49 nanoflowers. Together with the cathode of activated carbon coupled with redox electrolyte of FeBr3, these pseudocapacitive anodes are utilized to construct sandwich‐like quasi‐solid‐state asymmetric supercapacitors. Such devices exhibit high performance, featuring big and stable capacitances as well as high power and energy densities.