A 500 mAh Li–Air battery is assembled using cell components and a structure that enable the construction of a high specific energy battery. Carbon nanotubes are used in the cathode so that the pore volume can be adjusted to reduce the amount of electrolyte while a high specific capacity of the cathode is maintained. Polymer ionic liquid is used in the electrolyte layer, and the weight of the cathode and electrolyte layer is 5.5 mg cm−2. The cell structure, which is prepared by folding a three-layer assembly of Li metal/electrolyte layer/cathode, reduces the weight contribution of the sealing and manifold materials. By folding the three-layer assembly ten times, a 500 mAh Li–Air battery with dimensions of 7 cm × 1 cm × 0.23 cm is prepared. The battery yields an areal capacity of 3.6 mAh cm−2 and a specific capacity of 4400 mAh gcarbon −1, and the resulting specific energy and energy density are 1230 Wh kg−1 and 880 Wh L−1, respectively. The battery is able to cycle seven times at 500 Wh kg−1 before an abrupt decrease in its capacity is noted.