Would it be possible to perhaps fit one of these inside the housing of a flashlight and then use the external transmitter base, the output at 5vdc then feed that very small TP4056 Li Ion charger?
Well, forstarters. The alu body of a light would block the EM that those use, it would have to be on the outside, then make battery contact on the inside some how. The easiest way would be to have a large ish light probably a 4p or 3p light and put the induction coil on the bottom and then epoxy over it or something