Best battery for arduino project

I am making a project which includes arduino nano v.3.0 , 0.96" OLED Display, HC05 bluetooth module and voice recognition module V3.

I need a rechargeable battery which is :

  • safe and less volatile
  • can sustain moderately high temp as 35 degree celsius
  • cheaper
  • small and compact
  • can power the model for 3-4 hours

The main concern is the safety of the battery. The temperature may be avoided by thermal shielding. I was thinking of going for 3.7v 100 mah LiPo battery.

Any suggestions?

Any suggestions?

Measure the average current draw in mA, multiply that by 4 hours, and buy a battery with at least that capacity in mAh.

LiPo batteries are not "safe and less volatile". They absolutely require the proper charging circuitry.

LiPo batteries are not "safe and less volatile".

Oh so which one should I prefer . 18650 li ion batteries are bulky. And for charging circuit , We will be making that.