Low input to close switch
There exist two complementary types of transistors. E.g. for MOSFETs, these are called P-channel or N-channel. You could use a P-channel type for your task. Inserted in the positive voltage path, you can switch the cell off by applying low voltage (0V) to the gate. You would also need a resistor to pull the gate to positive voltage when the MOSFET is not switched off. And you need to make sure that the Arduino does not get too high voltage at its pin.