Abstract: In some implementations, a transaction card includes a card body having a first surface and a second surface opposite the first surface, and the card body may be in a configuration that defines a storage area for a physical key. The transaction card may include at least one of an integrated circuit chip or a magnetic stripe accessible from at least one of the first surface or the second surface of the card body. The transaction card may include a connecting element to connect the physical key to the card body. The connecting element may be configured to enable movement of the physical key between a storage position, in which at least a portion of the physical key occupies the storage area, and a use position, in which at least a portion of the physical key is outside of the storage area.

Abstract: The present disclosure provides compositions including thermo-electro-chemical converter, methods of converting thermal energy into electrical energy, and the like. In general, embodiments of the present disclosure can be used to convert thermal energy into electrical energy by way of a chemical process.

Abstract: The present disclosure provides compositions including thermo-electro-chemical converter, methods of converting thermal energy into electrical energy, and the like. In general, embodiments of the present disclosure can be used to convert thermal energy into electrical energy by way of a chemical process.