The mechanical flexibility of an electrochromic device is indispensable for the radiative thermal management of objects with various shapes of surfaces. Here, we use a porous nylon film as the separator to prevent the contact between the working electrode (ultra-wideband transparent electrode) and the counter electrode (Cu foil). The 2 cm × 2 cm device can switch between cooling and heating modes when bent to different shapes, making it suitable for human skin thermal management (Figure ). The 6 cm × 6 cm large-scale flexible device (Figure ) is attached to the human knees (Figure ). The thermal camera images elucidate that the apparent temperature can be uniformly tuned with nearly 10 ℃ contrast, proving the Cu-aqueous electrochromism applicable to flexible and large-scale thermal management.