An electrochemical device, comprising: a positive electrode current collector; a plurality of positive electrodes disposed on a first surface of the positive electrode current collector; first and second solid electrolyte layers having different compositions from one another disposed sequentially as a multi-layered structure on the plurality of positive electrodes; a negative electrode disposed on the second solid electrolyte layer; and a negative electrode current collector disposed on the negative electrode; and wherein the electrochemical device comprises: a first protruding portion comprising a positive electrode of the plurality of positive electrodes, wherein adjacent positive electrodes define a first indented portion between the adjacent positive electrodes of the plurality of positive electrodes, wherein the solid electrolyte layers comprise a second protruding portion and a second indented portion, wherein the second protruding portion is disposed on the first protruding portion and wherein the second indented portion is on the first indented portion, and wherein: the first solid electrolyte layer comprises a third protruding portion and a third indented portion, the third protruding portion being disposed on the first protruding portion and the third indented portion disposed on the first indented portion; and the second solid electrolyte layer comprises a fourth protruding portion and a fourth indented portion, the fourth protruding portion disposed on the third protruding portion and the fourth indented portion disposed on the third indented portion; and characterized in that the thickness of the first solid electrolyte layer on a first surface of the positive electrodes, the first surface of the positive electrode being orthogonal to the first surface of the positive electrode current collector, at a location proximate to the positive electrode current collector is greater than its thickness at a location distal to the positive electrode current collector, and in that the thickness of the second solid electrolyte layer at a location proximate to the positive electrode current collector is less than its thickness at a location distal to the positive electrode current collector. a positive electrode current collector; a plurality of positive electrodes disposed on a first surface of the positive electrode current collector; first and second solid electrolyte layers having different compositions from one another disposed sequentially as a multi-layered structure on the plurality of positive electrodes; a negative electrode disposed on the second solid electrolyte layer; and a negative electrode current collector disposed on the negative electrode; and wherein the electrochemical device comprises: a first protruding portion comprising a positive electrode of the plurality of positive electrodes, wherein adjacent positive electrodes define a first indented portion between the adjacent positive electrodes of the plurality of positive electrodes, wherein the solid electrolyte layers comprise a second protruding portion and a second indented portion, wherein the second protruding portion is disposed on the first protruding portion and wherein the second indented portion is on the first indented portion, and wherein: the first solid electrolyte layer comprises a third protruding portion and a third indented portion, the third protruding portion being disposed on the first protruding portion and the third indented portion disposed on the first indented portion; and the second solid electrolyte layer comprises a fourth protruding portion and a fourth indented portion, the fourth protruding portion disposed on the third protruding portion and the fourth indented portion disposed on the third indented portion; and a first protruding portion comprising a positive electrode of the plurality of positive electrodes, wherein adjacent positive electrodes define a first indented portion between the adjacent positive electrodes of the plurality of positive electrodes, wherein the solid electrolyte layers comprise a second protruding portion and a second indented portion, wherein the second protruding portion is disposed on the first protruding portion and wherein the second indented portion is on the first indented portion, and wherein: the first solid electrolyte layer comprises a third protruding portion and a third indented portion, the third protruding portion being disposed on the first protruding portion and the third indented portion disposed on the first indented portion; and the second solid electrolyte layer comprises a fourth protruding portion and a fourth indented portion, the fourth protruding portion disposed on the third protruding portion and the fourth indented portion disposed on the third indented portion; and characterized in that the thickness of the first solid electrolyte layer on a first surface of the positive electrodes, the first surface of the positive electrode being orthogonal to the first surface of the positive electrode current collector, at a location proximate to the positive electrode current collector is greater than its thickness at a location distal to the positive electrode current collector, and in that the thickness of the second solid electrolyte layer at a location proximate to the positive electrode current collector is less than its thickness at a location distal to the positive electrode current collector.