Tank interior lining - sheet method

A method for manufacturing a polymeric inner liner for a storage tank, in particular for a hydrogen storage tank, wherein the method comprises the steps of: providing a cylindrical body made from polymer material and comprising a structural layer and a barrier layer, said cylindrical body having a first open end and a first peripheral connection tab at said open end; providing a dome-shaped end cap made from polymer material, the end cap having a base with a cross-section essentially corresponding to a cross-section of the first open end of the cylindrical body and having a second peripheral connection tab at a peripheral end portion of said end cap; placing the end cap with its base onto the first open end of the cylindrical body and with said first and second peripheral tabs in contact with each other; and welding both connection tabs together. Storage tank made using such a liner and use of such a tank for storing hydrogen.