Method of producing electrode, method of producing battery, electrode, and battery

A method of producing a battery, comprising:

• preparing a slurry by mixing active material particles, capsule-shaped particles, a binder, and an aqueous solvent;
• applying the slurry to a surface of a substrate to form a coating film;
• drying the coating film by heating to form an active material layer;
• compressing the active material layer to produce an electrode;
• assembling a battery that includes the electrode and an electrolyte solution;
• and
• performing thermal aging of the battery, wherein
• the electrolyte solution includes an organic solvent,
• each of the capsule-shaped particles includes a thermoplastic resin,
• the thermoplastic resin softens upon contact with the electrolyte solution, and
• when the thermoplastic resin softens, the capsule-shaped particles shrink to form voids in the active material layer.

An electrode comprising:

• a substrate;
• and
• an active material layer, wherein
• the active material layer is placed on a surface of the substrate,
• the active material layer includes active material particles, a resin fragment, and a binder,
• voids are formed in the active material layer,
• each of the voids has a diameter larger than a particle size of the active material particles,
• the resin fragment is placed inside the voids, and
• the resin fragment includes a thermoplastic resin.