➀ A research team at Kumamoto University has developed a novel, pore-free graphene oxide (GO) film with superior hydrogen ion barrier properties. The film shows up to 100,000 times better hydrogen ion barrier performance compared to standard GO films. ➁ This innovation is significant in improving protective coatings for various applications and could lead to the development of coatings with enhanced protective qualities. ➂ The team plans to utilize the hydrogen ion barrier performance for practical applications while addressing the challenges of the 'pores' in the GO structure.