Three hundred micron squared all-solid-state Li ion secondary battery fabricated by Si very large scale integration technology

Fabrication and charge/discharge behaviors of all-solid-state individual Li ion secondary battery with a Li free anode and a polymer electrolyte are studied. The battery with a 300×300μm2 area, consisting of multiple layers (Poly Si anode/a poly methacrylate acetate (PMMA)/LiMn2O4), is prepared by combining a sol–gel spin-coating method and Si very-large-scale integration technologies. The PMMA solid electrolyte containing LiClO4 for the battery is embedded into an individual trench (300×300μm2 in area and 2.0μm in depth) of a double insulating layer (Si3N4/SiO2), which is directly stacked on a poly Si layer, leading to a Li free anode. The individual battery demonstrates a specific capacity of 3.70nAh/cm2 obtained for the charge of 3nA and discharge of 10pA. A Rutherford backscattering study of Cl in the PMMA electrolyte suggests that 2.3×1021cm−3 of Li is included in the electrolyte.