This paper presents a high-stability, single-phase hybrid polyelectrolyte (SPHP) applied in a large EC device (5×10 cm
2
) using WO
3
(electrochromic) and CeO
2
-TiO
2
(counter-electrode-ion storage) electrodes, both produced by Leibniz-Institut of New Materials (Leibniz-INM, Germany). The electrochromic device exhibited excellent color and bleach reversibility, high coloration efficiency (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). Its remarkable behavior and high stability render this material an excellent candidate for application in electrochromic devices.