A secondary battery comprising: a positive electrode; a negative electrode; and an electrolyte, wherein the electrolyte comprises at least one of a liquid nonaqueous electrolyte and a gel nonaqueous electrolyte, and wherein at least one of the positive electrode and the negative electrode is an electrode comprising: an active material-containing layer comprising active material particles, ferroelectric particles, and solid electrolyte particles having a Li ion conductivity of 1 × 10 -10 S/cm or more at 25°C, wherein a ratio (FE contact) of a number of the ferroelectric particles in contact with the active material particles relative to a number of the ferroelectric particles included in the active material-containing layer is 85% or more, and a ratio (SE non-contact) of a number of the solid electrolyte particles not in contact with the active material particles relative to a number of the solid electrolyte particles included in the active material-containing layer is 30% or more, and wherein the ratio (FE contact) and the ratio (SE non-contact) are determined as outlined in the section "Scanning Electron Microscope-Energy Dispersive X-ray Spectroscopy (SEM-EDX)" of the description and wherein the Li ion conductivity is determined as outlined in the section "Measurement of Ion Conductivity of Solid Electrolyte Particle" of the description. wherein the electrolyte comprises at least one of a liquid nonaqueous electrolyte and a gel nonaqueous electrolyte, and wherein at least one of the positive electrode and the negative electrode is an electrode comprising: an active material-containing layer comprising active material particles, ferroelectric particles, and solid electrolyte particles having a Li ion conductivity of 1 × 10 -10 S/cm or more at 25°C, wherein a ratio (FE contact) of a number of the ferroelectric particles in contact with the active material particles relative to a number of the ferroelectric particles included in the active material-containing layer is 85% or more, and a ratio (SE non-contact) of a number of the solid electrolyte particles not in contact with the active material particles relative to a number of the solid electrolyte particles included in the active material-containing layer is 30% or more, and wherein the ratio (FE contact) and the ratio (SE non-contact) are determined as outlined in the section "Scanning Electron Microscope-Energy Dispersive X-ray Spectroscopy (SEM-EDX)" of the description and wherein the Li ion conductivity is determined as outlined in the section "Measurement of Ion Conductivity of Solid Electrolyte Particle" of the description. an active material-containing layer comprising active material particles, ferroelectric particles, and solid electrolyte particles having a Li ion conductivity of 1 × 10 -10 S/cm or more at 25°C, wherein a ratio (FE contact) of a number of the ferroelectric particles in contact with the active material particles relative to a number of the ferroelectric particles included in the active material-containing layer is 85% or more, and a ratio (SE non-contact) of a number of the solid electrolyte particles not in contact with the active material particles relative to a number of the solid electrolyte particles included in the active material-containing layer is 30% or more, and wherein the ratio (FE contact) and the ratio (SE non-contact) are determined as outlined in the section "Scanning Electron Microscope-Energy Dispersive X-ray Spectroscopy (SEM-EDX)" of the description and wherein the Li ion conductivity is determined as outlined in the section "Measurement of Ion Conductivity of Solid Electrolyte Particle" of the description.