Hierarchically Porous Carbon with Manganese Oxides as Highly Efficient Electrode for Asymmetric Supercapacitors

Abstract

A promising energy storage material, MnO2 /hierarchically porous carbon (HPC) nanocomposites, with exceptional electrochemical performance and ultrahigh energy density was developed for asymmetric supercapacitor applications. The microstructures of MnO2 /HPC nanocomposites were characterized by transmission electron microscopy, scanning transmission electron microscopy, and electron dispersive X-ray elemental mapping analysis. The 3-5 nm MnO2 nanocrystals at mass loadings of 7.3-10.8 wt % are homogeneously distributed onto the HPCs, and the utilization efficiency of MnO2 on specific capacitance can be enhanced to 94-96 %. By combining the ultrahigh utilization efficiency of MnO2 and the conductive and ion-transport advantages of HPCs, MnO2 /HPC electrodes can achieve higher specific capacitance values (196 F g(-1) ) than those of pure carbon electrodes (60.8 F g(-1) ), and maintain their superior rate capability in neutral electrolyte solutions. The asymmetric supercapacitor consisting of a MnO2 /HPC cathode and a HPC anode shows an excellent performance with energy and power densities of 15.3 Wh kg(-1) and 19.8 kW kg(-1) , respectively, at a cell voltage of 2 V. Results obtained herein demonstrate the excellence of MnO2 /HPC nanocomposites as energy storage material and open an avenue to fabricate the next generation supercapacitors with both high power and energy densities.

Rescaling of metal oxide nanocrystals for energy storage having high capacitance and energy density with robust cycle life

“…(E) Cycling performance of asymmetric full-cell devices based on NiO-a/gr and NG electrodes in addition to that using NiO-a/gr and NG electrodes at a current density of 12 A g −1 . (F) Ragone plot of capacitors using NiO-a/gr and NG electrodes, NiO-a/gr and AC electrodes, and other data reported in the literature (31)(32)(33)(34)(35)(36)(37). All data in this figure are based on the asymmetric capacitor with the total mass of both electrodes.…”

“…5F and SI Appendix, section S13). These energy and power densities are excellent compared with those of nickel-oxide-based capacitors (31,32), nickel-hydroxide-based capacitors (33)(34)(35), and manganese-oxide-based asymmetric capacitor devices (36,37).…”

Self‐Assembled 3D Graphene‐Based Aerogel with Co3O4 Nanoparticles as High‐Performance Asymmetric Supercapacitor Electrode

“…[30,31] In contrast, hierarchically porousc arbon (HPC) that possesses especially well-defined and interconnected micropores, mesopores, and macropores is considered to be ap romising electrode material for supercapacitors owing to the combined advantages of microporous carbons and meso-/macroporous carbons:h igh specific surfacea rea, large pore volume, adjustable hierarchical pore structure, and good electric conductivity. [32][33][34] Herein, we demonstrated an asymmetrics upercapacitor deviceb ased on the 3D Co 3 .I na ddition, the 3D Co 3 O 4 -RGO aerogel//HPC asymmetric supercapacitor also shows ag ood cycling performance, with 92.92 %c apacitance retention after 2000 cycles. Furthermore, three CR2032 coin-type asymmetrics upercapacitors in series were able to poweru pared LED for 1h after a3 0s charging,i ndicating its application potential for commercial viability.…”

Efficient conversion of waste polyvinyl chloride into nanoporous carbon incorporated with MnOx exhibiting superior electrochemical performance for supercapacitor application

“…As a result, Fig. 7d their electrochemical performance was much enhanced, compared with HPC [36]. As are well reported, in such a hybrid electrode configuration, the carbon substrates acts highly conductive current collectors, the interconnected porosity serves as continuous pathway for electrolyte diffusion, and the nanoscopic active MnO x phase shortens solid-state transport distance for ions into the oxide materials [37].…”

“…5b, d, f demonstrate the magnified HRTEM images and corresponding SAED patterns. The well-dispersed MnO x crystals with interlayer spacing of 0.22 ~ 0.23 can be easily observed, which can be indexed to the (200) plane of Mn 3 O 4 [35] or (101) plane of MnO 2[36]. When incorporating with low contents of Mn species, the SAED pattern displays the ambiguous diffraction rings, somewhat similar to amorphous carbon.…”