Abstract：
Flexible electrochromic devices have attracted considerable attention in recent years due to their great potential in smart multifunction electrochromic energy storage devices and wearable intelligent electronics. Herein, we present an inorganic flexible Li-based electrochromic energy storage device (EESD) by combining a Prussian white@MnO2-composited electrode (PWM) and sputtering-made WO3 electrode. The synergistic effect of Prussian white and MnO2 plays a positive role both in energy storage and electrochromic property of the EESD. Its energy level can be quantified by the transmittance spectrum and chrominance difference, and its charging-discharging process can be monitored in real time by optical modulation at special wavelength. Specifically, the EESD can endure a 10,000 times cyclic voltammetry cycle without obvious degradation at wide voltage windows (-2 to 2.5 V) and realize a high coloration efficiency (77.6 cm2/C) with 35% optical modulation at 510 nm. In terms of energy storage performance, the EESD demonstrates excellent volumetric energy/power density (1.25 W cm-3/13.2 mWh cm-3) and remarkable stability with close to 98.3% capacitance retention and 99.4% coulombic efficiency after more than 4000 cycles. Its charging and discharging degree can be visualized in different spectral regions. There are 40% transmittance change for charging in the blue light region (450-480 nm) and 45% transmittance change for discharging in the red light region (620-750 nm). Based on its multicolor property, a quantitative indicator of charge state is achieved by the linear dependence of real-time chrominance change as stored or released charge. The ∼11 mC/cm2 stored charge capacity can cause an ∼11 increase in chrominance difference ΔE value, while ∼7 mC/cm2 discharge capacity can cause a ΔE value increase of ∼4. This work provides an efficient strategy to develop portable multicolor-integrated EESDs toward high performance and long stability.
摘要：
近年来,柔性电致变色器件因其在智能多功能电致变色储能器件和可穿戴智能电子产品中的巨大潜力而受到广泛关注。在这里，通过结合普鲁士白色@MnO2复合电极（PWM）和溅射制成的WO3电极，我们提出了一种无机柔性Li基电致变色储能器件（EESD）。普鲁士白和MnO2的协同作用对EESD的储能和电致变色性能均有积极作用。其能级可以通过透射光谱和色度差来量化，其充放电过程可以通过特殊波长的光调制实时监测。具体来说,EESD可以承受10,000次循环伏安循环，在宽电压窗口（-2至2.5V）下没有明显降解，并在510nm处具有35％的光学调制实现了高着色效率（77.6cm2/C）。在储能性能方面，EESD表现出优异的体积能量/功率密度(1.25Wcm-3/13.2mWhcm-3)和显著的稳定性,在超过4000次循环后具有接近98.3%的电容保持率和99.4%的库仑效率。可以在不同的光谱区域中可视化其充电和放电程度。对于在蓝光区域(450-480nm)中的充电,存在40%的透射率变化,对于在红光区域(620-750nm)中的放电,存在45%的透射率变化。基于它的多色属性，电荷状态的定量指标是通过存储或释放电荷时实时色度变化的线性依赖性来实现的。~11mC/cm2存储的电荷容量可以导致色度差ΔE值增加~11，而~7mC/cm2放电容量可导致ΔE值增加~4。这项工作提供了一种有效的策略来开发便携式多色集成EESD，以实现高性能和长稳定性。
