You need to start at the beginning.
P=I*E and E=I*R .
These equations are for DC. The trend in the USA is to also use them for AC, but ONLY for estimating.
P= power (Watts
I= current (amps
E= voltage (volts
R= resistance (ohms
Truth: Power in can not exceed power out.
You already know this. Make a pendulum with a string and a weight (mass). When the pendulum is set into motion it can not ever go higher than its launch point. Another interesting point is that without outside influence the motion will decay. If the mass on your pendulum had a mass of 1kg and the length of the string was 1 m and midway through it's swing it struck your automobile you might chip the paint maybe even dent it. If the mass was 1000kg you may knock the car off it's wheels.
Conceptualize: When your phone battery, is providing the absolute maximum power that the phone could possibly demand P would be less than one watt.
Find a low wattage light bulb, 10 watts or less. Can you hold your hand on it? Try (don't try) that with a 100 watt bulb.
I'm rambling. The battery you want to use does not have the capacity to do what you want. I do not think that the battery could even provide 10 watts without damage to itself. At 10 watts or more the battery could even be explosive.
Get yourself a Volt/ohm meter, a small battery (12 volts) and a couple of light bulbs (try a 12v car signal or brake light). Learn how to take resistance, voltage, and current measurements. Try different configurations with this setup. (series and parallel with the light bulbs). See what happens, take notes, make a table of voltage, current, resistance, calculated power, and brightness for each bulb for each configuration.
Rap up:
You need to start at the beginning.
Arm your curiosity with knowledge.
Have fun.
Be safe.
Make cool things.