A group of University graduates Carnegie Mellon in the US have developed a mechanism that can be integrated into shoes and turns them into chargers smartphones. 
The mechanism is called SolePower Insoles and according to its manufacturers, if it is placed in a pair of shoes, the owner will be able to walk for a total of an hour with them charges his device completely.
The kinetic energy of the legs is transferred to the mechanism by activating a mini-generator that charges the battery of the phone via a cable. In the first instance, the mechanism has proven to be operationally integrated into sports shoes, but researchers claim it can work on other types of shoe.
