Abstract: Embodiments described herein relate to electrochemical cells and production thereof under high pressure. In some aspects, a method of producing an electrochemical cell can include disposing a cathode material onto a cathode current collector to form a cathode, disposing an anode material onto an anode current collector to form an anode, and disposing the anode onto the cathode in an assembly jig with a separator positioned between the anode and the cathode to form an electrochemical cell, the assembly jig applying a force to the electrochemical cell such that a pressure in the cathode material is at least about 3,500 kPa. In some embodiments, the cathode material can be a first cathode material, and the method can further include disposing a second cathode material onto the first cathode material. In some embodiments, the first cathode material can include silicon. In some embodiments, the second cathode material can include graphite.