Aqueous Electrolyte-Based Electrochromic Devices with Co-Sputtered Ti-Doped WO₃ Amorphous Films

水系Zn2+基电致变色储能器件(ZEESDs)在智能窗与柔性显示领域具有重要应用价值。本研究针对当前ZEESDs发展中存在的材料结构稳定性不足、离子传输动力学效率低下等关键问题，采用磁控溅射技术制备Ti掺杂WO3基阴极薄膜。通过Ti元素掺杂调控策略，系统研究了Ti掺杂WO3薄膜对Zn2+存储动力学及电致变色性能的作用机制。实验结果表明，当Ti/W原子比为3.9%时，所得Ti-WO3-30薄膜展现出显著性能提升，薄膜在633 nm波长处实现87.23%的光学调制幅度，着色/褪色响应时间分别为12 s/7 s，着色效率达69.38 cm² C−1，该薄膜在0.5 mA cm−2电流密度下表现出102.78 mAh m−2的放电容量，经1000次循环后仍保持53.46%的ΔT (容量保持率62%)。基于该薄膜构建的器件在相同波长下获得51.81%的光学调制幅度，着色效率提升至58.82 cm² C−1，且界面动力学显著改善(响应时间10 s/11 s)。Ti掺杂诱导的氧空位形成有效增强了薄膜的电致变色性能，为高性能ZEESDs开发提供了新的材料设计思路。Aqueous Zn2+-based electrochromic energy storage devices (ZEESDs) hold significant promise for smart windows and flexible displays, yet their development is hindered by insufficient structural stability of electrode materials and sluggish ion transport kinetics. To address these challenges, this study employed a magnetron sputtering technique to fabricate Ti-doped WO3 cathode films, systematically investigating the role of Ti doping in regulating Zn2+ storage kinetics and electrochromic performance. Experimental results revealed that the Ti-WO₃-30 film (Ti/W atomic ratio of 3.9%) exhibited remarkable performance improvements: an optical modulation amplitude of 87.23% at 633 nm, rapid coloration/bleaching response times of 12 s/7 s, a high coloration efficiency of 69.38 cm2 C−1, and a discharge capacity of 102.78 mAh m−2 at 0.5 mA cm−2. After 1000 cycles, the film retained 53.46% of its initial ΔT (62% capacity retention). The assembled ZEESD device based on this film achieved an optical modulation amplitude of 51.81% at the same wavelength, a coloration efficiency of 58.82 cm2 C−1, and significantly improved interfacial kinetics (response times of 10 s/11 s). XPS analysis confirmed that Ti doping induced the formation of oxygen vacancies, which effectively enhanced charge transfer and ion diffusion, thereby boosting electrochromic performance. This work provides a novel material design strategy for developing high-performance ZEESDs through defect engineering and interfacial optimization.