Electronegativity value of gold is 2.5
Electronegativity value of Lithium is 1.0
difference is 2.5 - 1.0 = 1.5
The difference is less than 1.7
so it forms covalent bond.
( u have to remeber that if elctronegaticity value difference of two elements are 1.7 or greater than 1.7 its will be ionic bond. if its is less than 1.7 it forms a covalent bond.)