title: Strategies for liquid-liquid extraction of oxide particles for applications in supercapacitor electrodes and thin films.
abstract: Bottom-up and top-down liquid-liquid extraction methods have been developed for the transfer of colloidal metal oxide particles, synthesized in an aqueous phase, to organic phases. In such methods the agglomeration of the particles during the drying stage was avoided. Hexadecylamine was used as an extractor for MnO2particles in the bottom-up extraction to the 1-butanol phase and top-down extraction to the dichloromethane phase. The reduction of particle agglomeration facilitated the fabrication of MnO2-carbon nanotube composite electrodes for electrochemical supercapacitors with enhanced mixing of the individual components and active mass as high as 35mgcm-2. Electrochemical testing results showed superior performance of the composite MnO2-carbon nanotube electrodes, prepared by the bottom-up strategy. The new strategies allowed the fabrication of advanced electrodes, which showed a capacitance of 5.48Fcm-2at a scan rate of 2mVs-1, good capacitance retention at high scan rates and low resistance. In another conceptually new bottom-up strategy colloidal titania particles were modified during synthesis with 2,3,4-trihydroxybenzaldehyde, which allowed strong catecholate-type bonding to the Ti atoms on the particle surface. The Schiff base reaction with hexadecylamine at the liquid-liquid interface allowed for particle extraction. The extraction strategies developed in this investigation pave the way for agglomerate-free processing of advanced films, coatings and devices by colloidal methods.
authors.affiliation: Department of Mechanical Engineering, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4L7, Canada; Department of Materials Science and Engineering, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4L7, Canada.
authors.forename: Ri
authors.initials: R
authors.lastname: Chen
authors.affiliation: Department of Materials Science and Engineering, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4L7, Canada.
authors.forename: Mustafa S
authors.initials: MS
authors.lastname: Ata
authors.affiliation: Department of Materials Science and Engineering, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4L7, Canada.
authors.forename: Xinya
authors.initials: X
authors.lastname: Zhao
authors.affiliation: Department of Materials Science and Engineering, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4L7, Canada.
authors.forename: Amanda
authors.initials: A
authors.lastname: Clifford
authors.affiliation: Department of Mechanical Engineering, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4L7, Canada; Department of Materials Science and Engineering, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4L7, Canada.
authors.forename: Ishwar
authors.initials: I
authors.lastname: Puri
authors.affiliation: Department of Materials Science and Engineering, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4L7, Canada. Electronic address: zhitom@mcmaster.ca.
authors.forename: Igor
authors.initials: I
authors.lastname: Zhitomirsky
keywords: Carbon nanotube; Composite; Energy storage; Extraction; Film; Manganese dioxide; Supercapacitor; Titanium dioxide