Energy Harvesting ICs
There are several ICs out there that are specialized to harvest ambient energy such a motion, solar, etc. These are relatively easy to use but require an understanding of the chip you are using and what it is "tuned" for.
A supercapacitor (SC), sometimes ultracapacitor, formerly electric double-layer capacitor (EDLC)) is a high-capacity electrochemical capacitor with capacitance values up to 10,000 farads at 1.2 volt that bridge the gap between electrolytic capacitors and rechargeable batteries. They typically store 10 to 100 times more energy per unit volume or mass than electrolytic capacitors, can accept and deliver charge much faster than batteries, and tolerate many more charge and discharge cycles than rechargeable batteries. They are however 10 times larger than conventional batteries for a given charge.
Wearable induction refers to the idea of powering implants via induction using an external battery that inputs power through the skin.
Induction charging is possible through custom design however many device manufacturers are using the Qi (pronounced like chi) standard.