Active material structure, electrode structure including the same, secondary battery including the same, and method of fabricating the same

An active material structure comprising:

• a first active material layer on a second active material layer;
• an intermediate active material layer between the second active material layer and the first active material layer;
• first channels extending in the first active material layer and the intermediate active material layer in a first direction;
• and
• second channels extending in the second active material layer and the intermediate active material layer in a second direction intersecting the first direction,
• wherein the first channels and the second channels intersect each other in the intermediate active material layer.

An electrode structure comprising:

• a current collector layer;
• and
• an active material structure on the current collector layer,
• wherein
• the active material structure comprises a first portion and a second portion,
• the second portion of the active material structure is between the first portion of the active material structure and the current collector layer,
• the second portion of the active material structure comprises a first surface and a second surface opposite one another,
• the first surface is between the first portion of the active material structure and the second surface,
• the current collector layer comprises a third surface and a fourth surface opposite one another,
• the third surface is between the active material structure and the fourth surface,
• the active material structure comprises:
• first channels extending in a first direction parallel to the first surface of the current collector layer;
• and
• second channels intersecting the first channels and extending in a second direction parallel to the first surface of the current collector layer,
• the first surface of the current collector layer is exposed via the first channels, and
• the first surface of the second portion of the active material structure is exposed via the second channels.

A secondary battery comprising:

• a first electrode structure on a second electrode structure;
• and
• a separator between the second electrode structure and the first electrode structure,
• wherein the second electrode structure comprises:
• first active material lines arranged in a first direction;
• second active material lines arranged in a second direction intersecting the first direction;
• and
• intermediate active material lines provided between the first active material lines and the second active material lines in a third direction intersecting the first direction and the second direction, the intermediate active material lines provided in overlapping regions of the first active material lines and the second active material lines,
• wherein the first active material lines and the second active material lines are electrically connected by the intermediate active material lines.

A method of fabricating an active material structure, the method comprising:

• providing an active material film;
• forming first channels in the active material film, the first channels arranged in a first direction;
• forming second channels in the active material film, the second channels arranged in a second direction intersecting the first direction;
• and
• sintering the active material film,
• wherein the first channels comprise recessed regions of the active material film that are recessed to a first depth from a first surface of the active material film,
• the second channels comprise recessed regions of the active material film that are recessed to a second depth from a second surface of the active material film, the second surface of the active material film being opposite the first surface of the active material film, and
• a sum of the first depth and the second depth is greater than a thickness of the active material film measured in a third direction, the third direction intersecting the first direction and the second direction.