  We propose and analyze a universal method to obtain fast charging of a
quantum battery by a driven charger system using controlled, pure dephasing of
the charger. While the battery displays coherent underdamped oscillations of
energy for weak charger dephasing, the quantum Zeno freezing of the charger
energy at high dephasing suppresses the rate of transfer of energy to the
battery. Choosing an optimum dephasing rate between the regimes leads to a fast
charging of the battery. We illustrate our results with the charger and battery
modeled by either two-level systems or harmonic oscillators. Apart from the
fast charging, the dephasing also renders the charging performance more robust
to detuning between the charger, drive, and battery frequencies for the
two-level systems case.
