Synthesis and characterization of Lİ4Tİ5O12 (lto) based electrochromic structures for rechargeable electrochromic energy storage devices under different conditions

The development of modern energy storage technologies requires not only the achievement of high-capacity systems but also the integration of optical, functional, and aesthetic properties into these systems. In this context, the present study focuses on the development of Li4Ti5O12 (LTO) electrodes for innovative LTO-based electrochromic energy storage devices that are capable of combining both energy storage and optical switching functions within a single architecture, and on the evaluation of their electrochromic performance when used in conjunction with nickel oxide (NiO)-based electrochromic structures as counter electrodes. In this study, LTO thin films, known for their high structural stability and long cycle life, were synthesized on FTO glass substrates via the sol–gel/spin-coating method with Li/Ti ratios of 1/1, 1.5/1, and 2/1, while redox-active NiO thin films were fabricated by a hydrothermal method at temperatures ranging from 120 to 160 °C for durations of 4 to 6 h. The structural and optical properties of the obtained samples were characterized by XRD, SEM–EDX, and UV–Vis analyses, and their electrochromic performances were evaluated using CV and CA analyses. The experimental results demonstrate that the LTO–NiO system exhibits high optical modulation, fast response times, and reproducible electrochemical stability. Overall, this study represents an important step toward the development of multifunctional devices that integrate energy storage capability and optical performance within a single platform, and demonstrates that electrochromic and energy storage LTO electrodes can be successfully fabricated using the simple and cost-effective spin-coating technique.