Wireless charging :

A fast changing magnetic field interacts with the copper coil present inside the smartphone when you put a compatible smartphone on a wireless charger The magnetic field then produces electric energy in an enclosed loop that interacts with that magnetic field using electromagnetic induction

How wireless charging works 

In the late 1800s, Nikola Tesla successfully transmitted electricity through the air. He used a process called resonant-inductive coupling, which works by creating a magnetic field between a transmitter (which sends electricity) and a receiver (which receives the electricity) to power light bulbs in his New York City laboratory.

The same basic principle of inductive charging applies to smartphone wireless charging. 

An electromagnetic coil, the induction coil in a charging base, creates a magnetic field and is basically an antenna to transmit a field of energy. A second smaller coil in the phone receives and harvests the energy and its circuitry converts it back to usable energy for the battery.

There are Two Wireless charging the Qi standard and the PMA standard.

Both use the same inductive charging. The real key difference is in the amount of wavelength used.

PMA Wireless Charging: Short for Power Matters Alliance, the PMA wireless charging standard uses a wavelength of 277-357 kHz band.

Qi Wireless Charging: Pronounced "chee," the Qi wireless charging method was created by the WPC. This is the most commonly known and popular wireless charging method of the two standards and is what many brands use inside their wireless charging devices. It offers a 100-205 kHz band. 

Wireless charging is not as fast as plugging your device directly into the cable because wireless charger are typical maximum charging speed of a device is 10 watts. While you can find 15-watt chargers and stronger, 10 watts is average in some device and based on device capability too speed may varies. Fast chargers are something else entirely. You will commonly find fast charge adapters to offer anywhere from 10 to 65 watts, using the Quick Charge technology and Qi standard

NOTE:

Pictures are from internet source and Data too i.e: GOOGLE

That's All for the day regarding wireless charging technology and its Working and any doubts regarding let me know in comment section

Cheers

Thankyou

signing off,

Naveen_Yerradla