Toward Low-Cost and Sustainable Supercapacitor Electrode Processing: Simultaneous Carbon Grafting and Coating of Mixed-Valence Metal Oxides by Fast Annealing Publisher



Malaie K¹ ; Ganjali MR^{1, 2} ; Soavi F³ Show Affiliations
Source: Frontiers in Chemistry Published:2019

Abstract

There is a rapid market growth for supercapacitors and batteries based on new materials and production strategies that minimize their cost, end-of-life environmental impact, and waste management. Herein, mixed-valence iron oxide (FeO x ) and manganese oxide (Mn 3 O 4 ) and FeO x -carbon black (FeO x -CB) electrodes with excellent pseudocapacitive behavior in 1M Na 2 SO 4 are produced by a one-step thermal annealing. Due to the in situ grafted carbon black, the FeO x -CB shows a high pseudocapacitance of 408mF cm -2 (or 128 F g -1 ), and Mn 3 O 4 after activation shows high pseudocapacitance of 480 mF cm -2 (192 F g -1 ). The asymmetric supercapacitor based on FeO x -CB and activated-Mn 3 O 4 shows a capacitance of 260 mF cm -2 at 100 mHz and a cycling stability of 97.4% over 800 cycles. Furthermore, due to its facile redox reactions, the supercapacitor can be voltammetrically cycled up to a high rate of 2,000mV s -1 without a significant distortion of the voltammograms. Overall, our data indicate the feasibility of developing high-performance supercapacitors based on mixed-valence iron and manganese oxide electrodes in a single step. © 2019 Malaie, Ganjali and Soavi.