LITHIUM ION BATTERY

To provide a lithium ion battery with excellent charge/discharge characteristics and excellent rate characteristics.SOLUTION: A lithium ion battery according to the present invention includes a positive electrode having a positive electrode active material layer, a negative electrode having a negative electrode active material layer, a porous insulating layer disposed between the positive electrode and the negative electrode, and an electrolyte, and the porous insulating layer has a porous structure having a plurality of electrically insulating particles, is arranged adjacent to the negative electrode active material layer, and the median diameter of the plurality of electrically insulating particles is 1 μm or more and 5 μm or less, the porous insulating layer has a thickness of 5 μm or more and 50 μm or less, and the electrolyte contains a lithium salt and an ionic liquid.SELECTED DRAWING: Figure 1 【課題】本発明は、優れた充放電特性及び優れたレート特性を有するリチウムイオン電池を提供する。【解決手段】本発明のリチウムイオン電池は、正極活物質層を有する正極と、負極活物質層を有する負極と、前記正極と前記負極との間に配置された多孔質絶縁層と、電解液とを備え、前記多孔質絶縁層は、複数の電気絶縁性粒子を有する多孔質構造を有し、かつ、前記負極活物質層に隣接して配置され、複数の電気絶縁性粒子のメジアン径は、１μｍ以上５μｍ以下であり、前記多孔質絶縁層の厚さは、５μｍ以上５０μｍ以下であり、前記電解液は、リチウム塩と、イオン液体とを含むことを特徴とする。【選択図】図１