The most powerful lithium-ion battery is a cylindrical cell.
The cylindrical cell has the strongest physical strength because of its packaging. The active material on the electrode (lithium oxide and other partner materials) are in very small particle sizes, and is applied to a thin metal foil in a paste form with a binder. When dried, this material does not have much mechanical capabilities by itself.
In a cylindrical cell, many layers of the metal foils with active material coating are tightly wound into a rigid cylinder. Then a metal casing is over-wrapped with metal end-caps crimped tightly together. All these various metal components contribute to the mechanical strengths of a cell. See illustration below:
The pouch cell or Li-Poly is simply the active materials on metal foils sandwiched together like a booklet sealed inside a polymer film laminated with aluminum foil. See generic illustration below:
The 3rd kind of cell design is called prismatic cell. The active cell material is rolled up in a flat shape and placed in a metal can as show