BQ51025: How many coil factors effet the bq51025, how to improve the coil

Part Number: BQ51025

We have a project in DVT stage. The agency help us test two kind of coil sample ,one 10uH,one 13uH,but he think the coil is not good enough for the bq51025, he said the frequence with these two coil is to low  to work,"Tx 122khz output 9V@1A ",Our company use the wireless charge for the first time,we do not have much experience ,and the antenna company is also puzzled how to improve the coil to match the Bq51025. Could you help us test the coil with our phone in you lab ,so you can let us know how two improve the coil face to face.

Our phone requirement is : 

the Bq51025 out 9V 1.1A or 7V 1.4A (prefer to 9V)to charge 2S battery. We need ensure the phone could work properly both with TI TX for the 10W mode and other brand TX charging base for the 5W mode.