Hierarchical Activated Carbon–MnO2 Composite for Wide Potential Window Asymmetric Supercapacitor Devices in Organic Electrolyte

Abstract

The consumption of electrical energy grows alongside the development of global industry. Generating energy storage has become the primary focus of current research, examining supercapacitors with high power density. The primary raw material used in supercapacitor electrodes is activated carbon (AC). To improve the performance of activated carbon, we used manganese dioxide (MnO2), which has a theoretical capacitance of up to 1370 Fg−1. The composite-based activated carbon with a different mass of 0–20% MnO2 was successfully introduced as the positive electrode. The asymmetric cell supercapacitors based on activated carbon as the anode delivered an excellent gravimetric capacitance, energy density, and power density of 84.28 Fg−1, 14,88 Wh·kg−1, and 96.68 W·kg−1, respectively, at 1 M Et4NBF4, maintaining 88.88% after 1000 test cycles.

Potential of MnO2‐based composite and numerous morphological for enhancing supercapacitors performance

“…The asymmetric cell supercapacitors with AC as the anode demonstrated excellent gravimetric capacitance, energy density, and power density of 84.28 F/g, 14.88 W h/kg, and 96.68 W/kg, respectively, at 1 M organic electrolyte. 149 Activated carbon fiber yarns (CFY) and birnessite-type MnO 2 composite as a positive electrode and oxygen-functionalized carbon fiber yarn as a negative electrode exhibit a specific capacitance and energy density of 42.73 F/cm 3 (.11 A/cm 3 ) and 11.05 mW h/cm 3 in 2 M KOH respectively. 146 The high specific capacitance gained due to an interlinked 3-D nanostructure on the surface of MnO 2 @CFY is advantageous for ion transport and electron transfer, which exhibits great cycling as electrochemical performance.…”

“…The CNT-MnO 2 nanorods nanocomposite showed outstandingspecific capacitance of 674 F/g at 2 A/g with a good cycle life of 5000 cycles. 156 F I G U R E 6 (A) SEM morphology, (B) cyclic voltammetry of 0-20 MnO 2 mass percentage of the composite, (C) charge-discharge curve on different applied voltages (2-2.6 V), (D) capacity retention at current density 1 A/g for 1000 times of AC-MnO 2 nanoparticle composite, 149 (E) SEM images, (F) CV response at different scan rates (10-100 mV/s), (G) GCD plots, (H) cycling stability performance of Zn/MnO 2 composite, 150 (I) SEM images, (J) CV curves in .01-1 M KI with 1 M H 2 SO 4 , (K) GCD curves at 2 A/g .5 M KI, and (L) cycling stability after 500 cycles that retained 90%. 151 Recently, the high demand for reduced graphene oxide with transition metal oxides, especially for electrodes.…”

“…After 1000 cycles of testing, cell stability showed a nonsignificant decrease (maintaining up to 88%), indicating that cell performance was quite good (Figure 6D). The asymmetric cell supercapacitors with AC as the anode demonstrated excellent gravimetric capacitance, energy density, and power density of 84.28 F/g, 14.88 W h/kg, and 96.68 W/kg, respectively, at 1 M organic electrolyte 149 . Activated carbon fiber yarns (CFY) and birnessite‐type MnO 2 composite as a positive electrode and oxygen‐functionalized carbon fiber yarn as a negative electrode exhibit a specific capacitance and energy density of 42.73 F/cm 3 (.11 A/cm 3 ) and 11.05 mW h/cm 3 in 2 M KOH respectively 146 .…”

“…(A) SEM morphology, (B) cyclic voltammetry of 0–20 MnO 2 mass percentage of the composite, (C) charge–discharge curve on different applied voltages (2–2.6 V), (D) capacity retention at current density 1 A/g for 1000 times of AC–MnO 2 nanoparticle composite, 149 (E) SEM images, (F) CV response at different scan rates (10–100 mV/s), (G) GCD plots, (H) cycling stability performance of Zn/MnO 2 composite, 150 (I) SEM images, (J) CV curves in .01–1 M KI with 1 M H 2 SO 4 , (K) GCD curves at 2 A/g .5 M KI, and (L) cycling stability after 500 cycles that retained 90% 151 …”

Electrochemically Deposited MoS2 and MnS Multilayers on Nickel Substrates in Inverse Opal Structure as Supercapacitor Microelectrodes

“…Supercapacitors or electrochemical capacitors store electric charges through the unique separation of ions and charges at the microelectrode interface and form an electric double layer where the charges are separated. The electric double layer is also called electric double-layer capacitors (EDLCs), which are then divided into two categories, namely, electric double-layer capacitors and Faraday capacitors or pseudocapacitors (pseudocapacitance capacitors; PCs) according to the difference in the charge storage mechanisms [ 9 , 10 , 11 , 12 ]. The active material undergoes chemical reactions, mainly charge transfer storage, and pseudocapacitors tend to use transition metal oxides, sulfides, or conductive polymers as microelectrodes, and the charge storage mechanism is based on a mainly fast redox reaction but applies its electrochemical characteristics.…”