Reversible electrochemical mirror (REM) electrochromic devices with electrochemical tunability in multiple optical states are exciting alternatives to conventional electrochromic smart windows. Electrochromic devices are studied extensively, yet widespread adoptions have not been achieved due to problems associated with durability, switching speed, limited options on optical states, and cost. In this study, a REM electrochromic device based on CuSn alloy is developed, which offers highly reversible switching between transparent, greyish‐blue, and mirror states via reversible electrodeposition and dissolution. The alloying element, Sn acts as an electrochemical mediator, which facilitates the electrodeposition and dissolution of Cu. The CuSn‐based REM device shows superior cycling stability for 2400 cycles (transmittance mode) and 1000 cycles (reflectance mode). The electrodeposited CuSn alloy film is resistant to surface oxidation in ambient air, with a 2.9% difference in reflectance at 2000 nm after 3 days. In addition, the alloy film exhibits excellent NIR reflectance property with thermal modulation of 18.5 °C at a high temperature of 180 °C. The REM device with zero power consumption maintains its mirror state for at least 100 min, making it a promising candidate for energy‐efficient applications.

中文翻译：

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具有增强稳定性的准固态三态可逆电化学镜装置。

在多种光学状态下具有电化学可调性的可逆电化学镜（REM）电致变色器件是传统电致变色智能窗口的令人兴奋的替代方案。对电致变色器件进行了广泛的研究，但是由于与耐久性，开关速度，光学状态的选择有限以及成本有关的问题，尚未实现广泛的采用。在这项研究中，开发了一种基于CuSn合金的REM电致变色设备，该设备可通过可逆的电沉积和溶解在透明，灰蓝色和镜面状态之间提供高度可逆的切换。合金元素Sn充当电化学介质，可促进Cu的电沉积和溶解。基于CuSn的REM器件在2400个循环（透射模式）和1000个循环（反射模式）下显示出卓越的循环稳定性。电沉积的CuSn合金膜可抵抗环境空气中的表面氧化，三天后2000 nm处的反射率相差2.9％。另外，该合金膜在180℃的高温下具有18.5℃的热调制性，显示出优异的NIR反射特性。具有零功耗的REM设备至少可保持其镜像状态100分钟，使其成为节能应用的有希望的候选者。在180°C的高温下为5°C。具有零功耗的REM设备至少可保持其镜像状态100分钟，使其成为节能应用的有希望的候选者。在180°C的高温下为5°C。具有零功耗的REM设备至少可保持其镜像状态至少100分钟，使其成为节能应用的有希望的候选者。