Irreversibly changed during discharge

This photography habit of mine certainly generates some waste. Nearly all of the batteries in my battery graveyard have been used in my Speedlite and probably in the last twelve months. Note to self: buy some rechargeable ones. Meant to go out on the streets of York tonight for some nighttime photography, but we had our evening meal and I fell asleep. Woke up at 5 minutes to midnight. Thankfully I had in mind the battery pile for a possible shot in the future but I fear this is not as well set up as I would have hoped. But, it keeps my blipfoto journal alive and there are some pleasing elements to the photo.
Primary (single-use or "disposable") batteries are used once and discarded, the electrode materials are irreversibly changed during discharge. (With thanks to Mr Wikipedia)