TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Component: The mass volume ratio of antimony chloride, tin chloride dihydrate, polyethylene glycol 2000, and absolute ethyl alcohol is 228 g:3.2 g:0.23 g:50 ml.    TECHNOLOGY FOCUS - METALLURGY - Preferred Method: The method comprises adding anhydrous ethanol and antimony chloride (SbCl3) into ground conical flask; stirring at constant temperature; heating at 50 degrees C while stirring at controlled speed of 600 revolutions per minute to obtain solution A; putting anhydrous ethanol, covering agent polyethylene glycol 2000 and tin chloride dihydrate into another conical flask; stirring at constant temperature; heating at 50 degrees C while stirring at controlled speed of 600 revolutions per minute to obtain solution B; slowly dripping solution B to solution A at 50 degrees C; stirring at 600 revolutions per minute for 2 hours; aging for 24 hours to obtain colorless Sb doped SnO2 sol, in which antimony chloride, tin chloride dihydrate, polyethylene glycol 2000 and anhydrous ethanol have weight to volume ratio (g:g:g:ml) of (0.057-0.228):3.2:0.23:50; pre-treating base material basal body material by abrasive of type W20, W10 and W5; gradually grinding and polishing to obtain 304 stainless steel bipolar plate; degreasing with absolute ethyl alcohol for ultrasonic cleaning for 5 minutes; washing with deionized water; drying with nitrogen; adding aged Sb doped SnO2 sol into cup for 304 stainless steel bipolar plate treatment; performing dipping-lifting process; keeping uniform speed in lifting; pulling film after drying at 100 degrees C in oven for 30 minutes to form layer of uniform film coating in 304 stainless steel bipolar plate surface; repeating procedure until required thickness of thin film is achieved; putting 304 stainless steel bipolar plate into stainless steel high pressure reaction kettle lined with PTFE; adding reaction solution B into reaction kettle until volume is 70%; sealing; heating at 180 degrees C for 3 hours; naturally cooling; cleaning surface of deionized water; and drying with nitrogen in oven at 100 degrees C for 30 minutes to obtain 304 stainless steel bipolar plate with surface coated with Sb-doped SnO2 thin film coating. The dipping-pulling process is performed by impregnating 305 stainless steel bipolar plate in sol-gel solution for 20 seconds at 2 mm/s for 2 times. Preferred Component: The base material of 304 stainless steel bipolar plate is 10 mmx 35 mmx 2 mm.