BATTERY, SEPARATOR, ELECTRODE, PAINT, BATTERY PACK, ELECTRONIC APPARATUS, ELECTRIC VEHICLE, ELECTRICITY STORAGE DEVICE, AND POWER SYSTEM

Provided is a battery including a positive electrode, a negative electrode, an electrolytic solution, and a particle-containing resin layer that contains particles and a resin. A shape of the particles includes a plane, a plane rate of the particles is greater than 40% and equal to or less than 100%, and a refractive index of the particles is equal to or greater than 1.3 and less than 2.4.