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

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 (FeOx) and manganese oxide (Mn3O4) and FeOx-carbon black (FeOx-CB) electrodes with excellent pseudocapacitive behavior in 1 M Na2SO4 are produced by a one-step thermal annealing. Due to the in situ grafted carbon black, the FeOx-CB shows a high pseudocapacitance of 408 mF cm−2 (or 128 F g−1), and Mn3O4 after activation shows high pseudocapacitance of 480 mF cm−2 (192 F g−1). The asymmetric supercapacitor based on FeOx-CB and activated-Mn3O4 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 2,000 mV 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.

Supercapacitors in the Light of Solid Waste and Energy Management: A Review

“…The asymmetric supercapacitor based on FeO x -CB and activated Mn 3 O 4 exhibited excellent pseudocapacitive behaviors in 1 m Na 2 SO 4 electrolyte with a capacitance of 260 mF cm −2 . [127] Xu et al proposed a simple hydrothermal process to obtain binderless electrodes by directly growing molybdenum selenide (MoSe 2 ) nanosheets onto a Ti mesh network. The as-prepared electrodes revealed a specific capacitance of 525.5 F g −1 at a current density of 1 A g −1 with 0.5 m H 2 SO 4 electrolyte showing negligible capacitance loss even beyond 1700 cycles at 10 A g −1 .…”

“…The asymmetric supercapacitor based on FeO x ‐CB and activated Mn 3 O 4 exhibited excellent pseudocapacitive behaviors in 1 m Na 2 SO 4 electrolyte with a capacitance of 260 mF cm −2 . [ 127 ] Xu et al. proposed a simple hydrothermal process to obtain binderless electrodes by directly growing molybdenum selenide (MoSe 2 ) nanosheets onto a Ti mesh network.…”

“…To avoid risks of exposing harmful components of a supercapacitor to the environment after its end of life, research on the development of binder-less supercapacitors is also being carried out. [80,96,98,101,[126][127][128][129][130] While the scenario of waste management revolving around various electrochemical devices such as batteries has been much contemplated, reviews focusing on that of supercapacitors, in particular, are rather few and far between. In this review, some of the recent developmental advances in supercapacitors in the light of solid waste management and energy conservation are summarized.…”

“…To avoid risks of exposing harmful components of a supercapacitor to the environment after its end of life, research on the development of binder‐less supercapacitors is also being carried out. [ 80,96,98,101,126–130 ]…”

Ultrahigh Energy Density and Long-Life Cyclic Stability of Surface-Treated Aluminum-Ion Supercapacitors

“…It is well known that an ideal supercapacitor (unlike a battery) should not have R ct , but a semicircle can be formed because of the redox reaction in the aluminum anode and AlCl 4 – ion intercalation in a few layers of graphene. In addition, R ct may exist because of the electrical conductivity of graphene and electronic resistance induced by the contact between the active material and the current collector. , …”