In this paper, we discuss the high stability of a single-phase hybrid polyelectrolyte (SPHP) and nanocomposite hybrid polyelectrolyte (NHP) in a large electrochromic (EC) device (5cm x 10 cm) mounted with different electrodes. The electrochromic device (K-glass/FTO/WO3/SPHP/CeO2-TiO2/FrO/K-glass-ECI, K-glass/FTO/WO3/NHP/CeO2-TiO2/FrO/K-glass-ECII,) exhibited excellent color and bleach reversibility, high coloration efficiency (CE) (> 35 cm(2)/C) from the first cycle up to more than 60,000 CA cycles, and a maximum constant rate of deintercalation/intercalation (O-out/Q(in) = 1). Also, the life time of the EC device with Nb2O5:MO (K-glass/FTO/Nb2O5:O/SPHP/CeO2-TiO2/FrO/K-glass-ECIII) was prolonged to up to more than 10,000 cycles with a fairly stable coloration efficiency (around 19 cm(2)/C) and O-out/Q(in) = 1. The SPHP and NHP were tested in a large EC device with different configurations to evaluate its successful performance. In conclusion, its remarkable behavior and high stability render this material an excellent candidate for application in EC devices. (c) 2007 Elsevier Ltd. All rights reserved.