ENERGY STORAGE DEVICE

A method comprising providing a first electrode layer on a first portion of a substrate, providing an electrolyte layer on the first electrode layer, and providing a second electrode layer on the electrolyte layer. At least part of a current collector layer is provided on a second portion of the substrate. An electrically insulating material is deposited on an exposed surface of the first electrode layer and an exposed surface of the electrolyte layer. An electrically conductive material is deposited on the electrically insulating material to connect the second electrode layer to the at least part of the current collector layer.