To explain the water transport mechanism through cation intercalated GOM, we calculated the slip length (𝑙 𝑠 ) for the cation intercalated GOMs. We refer to Figure and SI section 2 for understanding the concept of slip length . Additionally, a detailed explanation and calculation of slip length based on our water flux and XRD measurements are discussed in SI section 2.1-Calculation of slip length. In brief, the water flux according to the HP equation was calculated based on the membranes thickness and interlayer space. In the calculation of the water flux, the available space for water transport in between the GO layer was estimated using the interlayer space from XRD measurements and the diameter of carbon atoms 2 .