title: Cheap, High-Performance, and Wearable Mn Oxide Supercapacitors with Urea-LiClO4Based Gel Electrolytes.
abstract: Here we report a simple, scalable, and low-cost method to enhance the electrochemical properties of Mn oxide electrodes for highly efficient and flexible symmetrical supercapacitors. The method involving printing on a printer, pencil-drawing, and electrodeposition is established to fabricate Mn oxide/Ni-nanotube/graphite/paper hybrid electrodes operating with a low-cost, novel urea-LiClO4/PVA as gel electrolyte for flexible solid-state supercapacitor (FSSC) devices. The Mn oxide nanofiber/Ni-nanotube/graphite/paper (MNNGP) electrodes in urea-LiClO4/PVA gel electrolyte show specific capacitance (Csp) 960 F/g in voltage region 0.8 V at 5 mV/s and exhibit excellent rates of capacitance retention more than 85% after 5000 cycles. Moreover, the electrochemical behavior of the MNNGP electrodes in urea-LiClO4/PVA at operating temperatures 27-110 °C was investigated; the results show that the MNNGP electrodes in urea-LiClO4/PVA exhibit outstanding performance (1100 F/g), even at 90 °C. The assembled FSSC devices based on the MNNGP electrodes in urea-LiClO4/PVA exhibit great Csp(380 F/g in potential region of 2.0 V at 5 mV/s, exhibiting superior energy density 211.1 W h/kg) and great cycle stability (less than 15% loss after 5000 cycles at 25 mV/s). The oxidation-state change was examined by in situ X-ray absorption spectroscopy. FSSC devices would open new opportunities in developing novel portable, wearable, and roll-up electric devices owing to the cheap, high-performance, wide range of operating temperature, and simple procedures for large-area fabrication.
authors.affiliation: National Synchrotron Radiation Research Center , Hsinchu 300, Taiwan.
authors.forename: Ming-Jay
authors.identifier: http://orcid.org/0000-0002-4542-5374
authors.initials: MJ
authors.lastname: Deng
authors.affiliation: National Synchrotron Radiation Research Center , Hsinchu 300, Taiwan.|Department of Applied Science, Group of Material Science and Engineering, National Hsinchu University of Education , Hsinchu 300, Taiwan.
authors.forename: Kai-Wen
authors.initials: KW
authors.lastname: Chen
authors.affiliation: National Synchrotron Radiation Research Center , Hsinchu 300, Taiwan.|Department of Applied Science, Group of Material Science and Engineering, National Hsinchu University of Education , Hsinchu 300, Taiwan.
authors.forename: Yo-Cheng
authors.initials: YC
authors.lastname: Che
authors.affiliation: National Synchrotron Radiation Research Center , Hsinchu 300, Taiwan.|Department of Applied Science, Group of Material Science and Engineering, National Hsinchu University of Education , Hsinchu 300, Taiwan.
authors.forename: I-Ju
authors.initials: IJ
authors.lastname: Wang
authors.affiliation: Department of Applied Science, Group of Material Science and Engineering, National Hsinchu University of Education , Hsinchu 300, Taiwan.
authors.forename: Chih-Ming
authors.initials: CM
authors.lastname: Lin
authors.affiliation: National Synchrotron Radiation Research Center , Hsinchu 300, Taiwan.
authors.forename: Jin-Ming
authors.initials: JM
authors.lastname: Chen
authors.affiliation: National Synchrotron Radiation Research Center , Hsinchu 300, Taiwan.
authors.forename: Kueih-Tzu
authors.initials: KT
authors.lastname: Lu
authors.affiliation: National Synchrotron Radiation Research Center , Hsinchu 300, Taiwan.
authors.forename: Yen-Fa
authors.initials: YF
authors.lastname: Liao
authors.affiliation: National Synchrotron Radiation Research Center , Hsinchu 300, Taiwan.
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Ishii
keywords: MnO2; X-ray absorption spectra; flexible supercapacitors; gel electrolyte; low-cost; wearable