Energy storage smart window with transparent-to-dark electrochromic behavior and improved pseudocapacitive performance

A carefully designed energy storage smart window (ESSW) was successfully demonstrated with transparent-to-dark electrochromic behavior and improved pseudocapacitive performance that constructed by Mo-doped WO 3 film electrode and MnO 2 nanoflake film electrode. These two electrodes were all synthesized by facile electrodeposition method which is simple, economic and easy-to-production. The proposed ESSW could change its color between transparent and dark with over 60% optical modulations in all visible bands (420–800 nm), which is satisfactory to the applications toward energy saving. Also, the areal capacitance of the ESSW reaches 19.1 mF cm −2 with working voltage window of 2.0 V so that just one single ESSW could power an LED bulb for more than 90 s. The complementary electrochromic behavior of the two electrodes guarantees the commendable electrochromic performance of the proposed ESSW, and the well-matched working potentials and areal capacitances of the asymmetric electrodes improve the pseudocapacitive performance. Such ESSW could have widely future applications toward energy saving and storing fields.