Can I plug my iphone into a 220v USB plug without the "cube"?

If your adapter has a 5v USB outlet it should work. However, be cautious about cheap and nasty end of third party USB adapters which may not be manufactured to the quality you expect from Apple branded equipment. Your Apple power adapter is designed to accept any AC voltage between 110 and 230v, so you only need to do the plug fitting conversion.

Also take a look at https://www.apple.com/shop/product/MD837AM/A/apple-world-travel-adapter-kit?fnode=97&fs=f%3Dadapter%26fh%3D458e%252B45b0 if your charging adapter uses the standard interchangeable duck heads.

Correction: I just managed to read the tiny writing on my Apple 12W power adapter, the input is rated for 100-240v.

Apple's iPhone chargers work with voltage anywhere in the world., 110, 115, 120, 220, 230, 240 and whatever else you might find. All that is needed is a mechanical adapter so that the plug fits into the receptacle.

Correction: I just managed to read the tiny writing on my Apple 12W power adapter, the input is rated for 100-240v.

If your eyes are good enough (mine aren't), you will probably see a reference to AC and DC (most likely they use the industry-standard icons). That's the reason for the 100V bottom figure.

Philly_Phan wrote:

Correction: I just managed to read the tiny writing on my Apple 12W power adapter, the input is rated for 100-240v.

If your eyes are good enough (mine aren't), you will probably see a reference to AC and DC (most likely they use the industry-standard icons). That's the reason for the 100V bottom figure.

For the record, the input power for normal charging adapters and power supplies are always AC but this has no connection to the voltage. The true reason for the range is because the normal domestic voltage for some countries including Japan is 100V, and the maximum is nominal 240V which used to be found here in UK. So, 100-240 means worldwide cover of any domestic mains (utility) power.