This invention discloses an electrochromic smart dimming film and its roll-to-roll preparation method. The dimming film employs an innovative four-layer structure, consisting of a first transparent conductive substrate, an electrochromic composite layer, a
composite electrolyte layer with both
ion conduction and storage functions, and a second transparent conductive substrate. By integrating the
ion storage function into the
electrolyte layer, the
ion migration path is significantly shortened, thereby achieving an ultrafast response of less than or equal to 0.5 seconds and an ultra-long cycle life of ≥100,000 cycles. Its preparation utilizes a fully wet roll-to-roll
coating process, including steps such as electrochromic layer
coating and curing,
electrolyte layer slot
coating, roll lamination, and low-temperature curing. The product of this invention features a simplified structure, superior performance, low cost, and suitability for
mass production, and can be widely applied in the automotive,
consumer electronics, and
building energy conservation fields.