Can I charge 1 cell Li-ion battery with a charger for 2 cells?
You need to change the 542K and 459k resistors in their typical application diagram shown here.

Page 7 shows the formula, and a quick calculation on my end suggests 272k for R1 and 3M for R2 for a float voltage of 3.6v (Assumes LiFePo4 chemistry)

Page 15 goes into details for another resistor configuration for a 3.6v cuttoff voltage using lower resistance values that may be easier to find high precision resistors for.