I tested a cell which had aluminum sulfate as its anode electrolyte (12 grams aluminum in 50 mL water and a pH of 3.2), and potassium hydroxide as the cathode electrolyte (5 grams of KOH in 200 g of water, pH of 12.3). The anode electrode was aluminum foil and the cathode was platinum. The OCV of the cell was 0.9V and when connected to a 1 kΩ resistor, the voltage was 0.324V
When I increased the concentration of KOH from 5 grams to 10 grams, and all other material concentrations were kept constant, the OCV decreased from 0.9V to 0.7V, but when I attached the 1kΩ resistor, the voltage increased to 0.42V.
I do not understand why increasing pH is causing the OCV to decrease, but increase the voltage under a load to increase.
I am guessing for the voltage under the load that maybe the higher concentration of KOH leads to more ions in solution thus increasing the current flow. But if this assumption/hypothesis were true, shouldn't the OCV also increase?
Can someone please help?
P.S. OCV is open circuit voltage