The invention is a cathode arrangement comprising a cathode housing (20) defining a space (16) for cathode material and comprising a cathode housing wall being permeable to an electrolyte, and a collector member made of carbon, having a first end part extending into the space (16) for cathode material and a second end part extending outside the space (16) for cathode material, and cathode particles (10), having a cylindric shape with a diameter of 2-5 mm and being extruded from carbon, are arranged in the space (16) for cathode material. The invention is, furthermore, an energy cell comprising the cathode arrangement, an arrangement for processing hydrogen gas comprising the cathode arrangement and use the energy cell applying seawater or salt water as an electrolyte. Furthermore, the invention is a method for manufacturing the cathode arrangement.