This sidewalk panels can charge your phone. Platio installed this panels around the Europe where sun can be the source of free energy for their people to use.

Many USB panels are installed in the pavement and charged by solar power. For environmental friendly and cost saving considerations, those panels are made from recycled plastic and have anti-slip glass.

So, on a sunny day, these panels can generate 900WH/M power. Some panels even used for powering Malls in the green quarter.
Now you can charge your phone anywhere when you are within these projects area.