Ultrahigh Effective Diffusion in Oxide by Engineering the Interfacial Transporter Channels

Mass storage and removal in solids always play a vital role in technological applications such as modern batteries and neuronal computations. However, they were kinetically limited by the slow diffusional process in the lattice, which made it challenging to fabricate applicable conductors with high electronic and ionic conductivities at room temperature. Here, we proposed an acid solution/WO₃/ITO sandwich structure and achieved ultrafast H transport in the WO₃ layer by interfacial job-sharing diffusion, which means the spatially separated transport of the H⁺ and e^- in different layers. From the color change of WO₃, the effective diffusion coefficient (D_eff) was estimated, dramatically increasing ≤10⁶ times and overwhelming values from previous reports. The experiments and simulations also revealed the universality of extending this approach to other atoms and oxides, which could stimulate systematic studies of ultrafast mixed conductors in the future.