Perovskite solar cell powered electrochromic batteries for smart windows

We design and construct a new type of solid-state electrochromic batteries powered by perovskite solar cells for smart windows. In addition to optical modulation, this integrated system can exhibit multifunctionality of solar energy harvesting, electrochemical energy storage and reutilization. The solid-state electrochromic batteries are composed of a reduced graphene (rGO)-connected bilayer NiO nanoflake array cathode and a WO3 nanowire array anode. The charge storage and release are accompanied by color changes (between transparent and blue) and relatively fast (2.5-2.6 s) and large optical modulation (up to 62% at the infrared range, 1000-2000 nm). The electrochromic batteries can act as a power source and exhibit a capacity of 75 mA h g(-1) at 1 A g(-1) and good cycling life.