Static electricity, the kind generated by shuffling your feet, is typically thousands to tens of thousands of volts but low amperage; it can fry electronics, especially small electronics, but it’s not a power source that can be easily sustained in order to charge a battery due to the very low amperage.
If you could regulate the voltage and somehow connect your body to the battery circuit, you could charge your phone, but it would take a ridiculously long time.
Let me ask you a question, would it quench your thirst to have a glass of water poured over you?
That will generate a high voltage, extremely low amperage static electric buildup along the friction surfaces.
We’re talking about 4KV, 1.2 mJoules for 10-5 amp seconds.
Phone chargers contain 2400mAh of charge running 5 volts at 3A.
So somehow, you need to convert an ultrahigh voltage and minuscule amperage to a low voltage and relatively high amperage over an extended period of time. You’ll lose some energy in the conversion, and as a result, you’d have to have around 300 people feeding power into the charging circuit with their feet, over an extended period, to build up enough power for a measurable charge.
You’d do better to charge it using a stationary bike and a dynamo, which results in significantly less conversion loss. Or, for that matter, a swing dynamo that generates current from the swing of your walk (some old watches do this).
same reason you cant fill a bucket by shooting 10mL of water at 3000psi into it
More like why you can’t fill a bucket by holding it in your left hand and dipping your right hand into a puddle.
You can. You just haven’t tried hard or long enough. Filming yourself and putting it on YouTube helps, too. Go on, champ!