Single-layer and multilayer graphene, method of manufacturing the same, object including the same, and electric device including the same

A secondary battery comprising:

• a positive electrode;
• and
• a negative electrode,
• wherein the negative electrode comprises:
• a negative current collector;
• a negative active material layer over the negative current collector, the negative active material layer having an uneven surface;
• and
• a plurality of graphene layers over the uneven surface,
• wherein a part of the plurality of graphene layers is in contact with the uneven surface,
• wherein a number of layers of the plurality of graphene layers is 50 or less,
• wherein each of the plurality of graphene layers has at least one pore, and
• wherein the pore of a first layer of the plurality of graphene layers does not overlap the pore of a second layer adjacent to the first layer of the plurality of graphene layers.

A secondary battery comprising:

• a positive electrode;
• and
• a negative electrode,
• wherein the negative electrode comprises:
• a negative current collector;
• a negative active material layer over the negative current collector, the negative active material layer having an uneven surface;
• and
• a plurality of graphene layers over the uneven surface,
• wherein a number of layers of the plurality of graphene layers is 20 or less,
• wherein each of the plurality of graphene layers has at least one pore, and
• wherein the pore of a first layer of the plurality of graphene layers does not overlap the pore of a second layer adjacent to the first layer of the plurality of graphene layers.