%0 Journal Article
%T Low-Charge-Carrier-Scattering Three-Dimensional ¦Á-MnO2/¦Â-MnO2 Networks for Ultra-High-Rate Asymmetrical Supercapacitors
%J -
%D 2019
%R https://doi.org/10.1021/acsaem.8b01592
%X The excessive concern over the energy density of supercapacitors is changing their applied direction while the power density is always overlooked. Supercapacitors should be considered as a high-power energy device rather than a neither fish nor fowl energy device. Herein, an ultrafine ¦Á-MnO2 needle was formed on ¦Â-MnO2 networks, not distributed randomly, but standing on the surface of ¦Â-MnO2 vertically forming an array structure with low-charge-carrier scattering. These novel structures possess a rational arrangement of the needles resulting in high capacitance (278.2 F g¨C1 for ¦Á-MnO2/¦Â-MnO2 networks) and excellent rate capability (41.0% remaining with the specific current increased from 0.25 to 64.0 A g¨C1). Asymmetrical supercapacitors fabricated by reduced graphene oxide (RGO) as the anode and as-prepared structures as the cathode deliver excellent electrochemical performance. Specifically, the devices give a favorable specific energy (29.8 W h kg¨C1) considering the weight of ¦Á-MnO2/¦Â-MnO2 and reduced graphene oxide (RGO) as well as ultrahigh specific power (64.0 kW kg¨C1) and excellent cyclic stability (>95% of initial capacitance remained after 10£¿000 cycles). This work opens new avenues for promoting high-power asymmetrical supercapacitors
%U https://pubs.acs.org/doi/10.1021/acsaem.8b01592