How do I increase the amount of electrons transferred in a battery?

I made a simple battery with $\ce{Al}$ as anode electrode with $\pu{0.7 M}$ aluminum sulfate electrolyte. Platinum is my cathode electrode with $\pu{2 x 10^-4 M}$ $\ce{KOH}$ solution. I am generating $\ce{85 mA}$ (my cell produced $\pu{0.04 V}$ under a $\pu{47 \Omega}$ load). How can I increase amount of electrons to increase the current produced by my cell?


My half cell reactions are 
\begin{align}
\ce{2Al &-> 2Al^3+ + 6e-}\\
\ce{3H2O + 6e- &-> 3H2 + 6OH-}
\end{align}


[![enter image description here](https://i.stack.imgur.com/6pC9c.jpg)](https://i.stack.imgur.com/6pC9c.jpg)


