Numerous high drain electronic devices work with 3.7V batteries. You can purchase a rechargeable 3.7 battery for flashlight or torches, for example. In most cases, a 3.7 battery is a Lithium-ion.
You can purchase batteries individually or in sets of two or more. Rechargers are available separately or in packs with several batteries. Stop being annoyed by short battery life on your electronics and choose a 3.7V battery.