Ultrafine Mn3O4 nanowires synthesized by colloidal method as electrode materials for supercapacitors with a wide voltage range. (1st December 2021)

• Record Type: Journal Article
• Authors: Fang, Qisheng; Sun, Mengxuan; Ren, Xiaohe; Cao, Baobao; Shen, Wenzhong; Li, Zhijie; Fu, YongQing
• Is Part Of: Journal of energy storage. Volume 44(2021)Part A
• Publication Date: 2021-12-01
• Subjects: Mn3O4 -- Ultrafine nanowires -- Supercapacitor -- Pseudo-capacitance -- Electrochemical property; Energy storage -- Periodicals; Energy storage -- Research -- Periodicals; 621.3126
• DOI: 10.1016/j.est.2021.103260
• Languages: English
• ISSNs: 2352-152X

Abstract

Highlights: Ultrafine Mn3 O4 nanowires with a diameter of 4.0 nm were synthesized using a facile colloidal method. Mn3 O4 nanowires show a large surface area of 175.1 m 2 g −1 and a large pore volume of 0.7960 cm 3 g −1 . Mn3 O4 nanowire electrode exhibit a predominant surface capacitive behavior, and shows a wide potential window of −0.5∼1.1 V and high specific capacitance of 433.1 F g -1 at 0.5 A g -1 . Mn3 O4 nanowires//active carbon device shows a high energy density of 26.68 Wh kg -1 at a power density of 442 W kg -1 . Abstract: Manganese oxide is considered an ideal pseudo-capacitive electrode material for supercapacitors due to its low cost, environmental friendliness and large theoretical capacity. However, it is difficult to obtain manganese electrodes with a high specific capacitance and a large voltage range. In this study, ultrafine Mn3 O4 nanowires with an average diameter of 4.0 nm were synthesized using a colloidal method. They have a large specific surface area of 175.1 m 2 g −1, and can provide numerous active sites to enhance their specific capacitances. They also show a large pore volume of 0.7960 cm 3 g −1, which can provide essential channels for ion transport during charging and discharging processes. The supercapacitor electrode made of these ultrafine Mn3 O4 nanowires exhibits a predominant surface capacitive behavior during charge/discharge processes, and achieves a large specific capacitance of 433.1 F g −1 at a current density of 0.5 A g −1 with a very wide voltage range from -0.5 to 1.1 V in 1 M Na2 SO4 electrolyte. An asymmetric supercapacitor (ASC) was assembled using a cathode electrode made of these ultrafine Mn3 O4 nanowires and an active carbon (AC) anode electrode, and a high energy density of 26.68 Wh kg −1 at a power density of 442 W kg −1 was achieved. The ASC showed a good cycling stability, and its capacitance value was still maintained at 75.8% after 64, 000 charge/discharge cycles.