Bioinspired Cellulose‐Based Ultra‐Slippery Film with Superior Transmittance, Anti‐Fouling and De‐Icing Properties for the Durable and Efficient Output of Solar Panels

High optical transmittance can endow solar panels with sufficient light energy intake, while anti‐fouling and anti‐icing properties ensure stable power generation in environments where dust, bird droppings, algae, and ice are prone to accumulate. A highly transparent and ultra‐slippery surface is promising for meeting these requirements. However, it remains a huge challenge to achieve superior transmittance, anti‐fouling, anti‐icing, and durability on the same surface to ensure high energy conversion efficiency for solar panels. Herein, a bioinspired cellulose‐based ultra‐slippery film (BCUSF) with an extremely low water sliding angle (SA = 0.4°) and high transmittance (≈95% of bake glass) is reported. Benefiting from the impressive slippery property, remarkably low ice adhesion strength (0.38 kPa), and superior self‐cleaning and anti‐fouling performances are also demonstrated. Moreover, the BCUSF exhibits excellent durability and robustness, maintaining a SA of 0.8° after suffering high shear at 9000 r min −1 . Accordingly, the BCUSF with highly comprehensive performance enables solar panels to maintain high energy‐conversion efficiency after repeated accumulation/cleaning of ice (ice adhesion strength = 0.91 kPa after 25 tests) and dust, or sand impact. It is envisioned that the BCUSF can boost the practical applications of slippery films on solar panels.