Can you use capacitor as a battery?

In a sense, a capacitor IS a battery. But a very small one. A typical 33uF capacitor will hold about 33uC - that is, 33uA (microamperes) per second. At 16V potential, that will be around 528uC of charge (or 528uA in a second).

In contrast, a 1.5V AA battery can typically provide between 1.5 and 1.8Ah (ampere-hours) at 1.5V. That is - a device drawing 1.8A (amperes) will keep running off of such a battery for about an hour. The same device would consume the charge stored in our 33uF capacitor in 1/54545th of a second.

So in the end - no, it's not likely that a capacitor would be a feasible means to store large amounts of charge.

Rather, capacitors are used wherever oscillating circuits are needed (a basic R-C oscillator can be built from a capacitor and a resistor), and wherever "voltage smoothing" is required - the amount of charge a capacitor holds wouldn't run a small pocket light, but it would be enough to "fill in the gap" if a momentary voltage drop occured in a line-powered device.

Capacitors are also used in this very manner to reduce ("de-couple") mains hum (50Hz or 60Hz, depending on the continent) by "filling the voids" that are left over in the rectified DC voltage when the AC voltage phase passes through 0V.