Question

How does increase in temperature of electrolyte decreases the internal resistance of a cell?

Answer 1

see first what is the nature of resistance in a material and in the electrolyte of a battery.
In any material the resistance means the opposition faced by the free electrons due to the ions. As temperature increase the ions starts oscillating more and more and thus the opposition or the resistance increases. But in a electrolyte the conduction is only due to the ions , whose movement increase with temperature and thus the conducance increases or resistance decreases.