1. An implantable medical device, comprising: a rechargeable battery; a coil for wirelessly receiving radiation from an external charger for recharging the rechargeable battery; a rectifier coupled to the coil for producing a DC voltage; circuitry for receiving the DC voltage and for protecting and controlling the charging of the rechargeable battery; wherein the rechargeable battery comprises: a first substrate comprising titanium; a first electrode on the first substrate; a second substrate; a second electrode on the second substrate; and an electrolyte and separator layer between the first electrode and the second electrode.