Coalescence inhibition of hydrous RuO2 crystallites prepared by a hydrothermal method

Coalescence of particulates accompanied with crystal growth upon annealing at/above 200 degrees C, found for hydrous RuO2 (RuO2 center dot nH(2)O) prepared by a sol-gel process, is effectively inhibited by the formation of RuO2 center dot nH(2)O nanocrystallites in a hydrothermal process. This thermal stability, attributable to the barrier originated from the lattice energy of crystallites, maintains high water content, nanocrystalline structure, and porous nature of RuO2 center dot nH(2)O annealed at elevated temperatures from 200 to 400 degrees C. A hydrothermal derived RuO2-based supercapacitor with high specific capacitance (ca. 200 F g(-1) measured at 100 mA cm(-2)) and a cycle lifetime longer than 40 000 cycles, resulting from thermal stability, is demonstrated.(c) 2006 American Institute of Physics.