Not flashlight this time
but Water Activation Eco-Battery
http://www.tinydeal.com/2pcs-1000mah-15v-aa-water-activation-battery-px2vwrr-p-136705.html
Some of your flashlights need batteries, we would like to recommend you this environmental friendly water activation battery.
Water activated, just need ordinary water to start working.
Have you ever used this kind of battery?
How do you like it?
Only 1000mAh and is best for low drain devices i.e. remote control, calculator.
Tested in X=Power Spirit XP-G R5 AA https://www.fasttech.com/products/0/10003046/1227900-x-power-spirit-ha-iii-cree-xp-g-r5-3-mode-115-lume
These are 3000mAh, can handle higher draw and are less expensive https://www.fasttech.com/products/0/10001898/1136600-nice-15v-3000mah-aa-lithium-batteries-2-pack
Just because it’s activated by water does not mean it’s environmental friendly. H)
It means the exact oposite 
It can be reused many times only with water is the greatest advantage I think.
This is the most outstanding feature compared to other batteries.
The water used to activate the battery can also be reused to do some cleaning as you like.
They can’t be reused.
FROM AQUACELL—“AQUACELL: THE WATER ACTIVATED ECO-BATTERY • An Aquacell battery is a clean, lightweight alternative to normal alkaline batteries. • It’s ideal for everyday use in devices with low to medium power consumption. • It weighs only 12 grams and will start to provide eco-friendly power only after water is added to the battery. • If properly stored before use, Aquacell batteries have an infinite shelf-life with no expiry date. • Why is it more eco friendly then a normal battery? Unlike alkaline batteries that use a steel casing, Aquacell uses recycled sustainable plastic. Most of the heavy metals are also removed and other dangerous materials such as Potassium Hydroxide commonly found in ordinary batteries. • Why does it weigh only 12 grams? The steel casing you will find on most other batteries are replacedwith a lightweight recycled plastic shell. Some of the heavy metals used in ordinary batteries are also taken out. • Do Aquacell batteries leak? If the battery’s screw-cap is securely closed, the battery will not leak - not even when the battery is drained to 0.0V (when most other batteries will start to leak). •Can you keep re-filling Aquacell batteries? No. Aquacell batteries are activated when you add water. Once they have expired, they can be recycled, but not recharged. • Does any liquid work to power Aquacell batteries? Most water-based liquids will work. However, we recommend only regular tap or bottled water to be used as that will give the best performance. • Are Aquacell batteries the same as normal batteries? Yes , they can be used just like normal batteries, but they need to be activated by water before you can use them.”
Tinydeal does seem to have the best price though, by far.
If they can take desert heat in the car, I might pick up a couple.
The refillable capability of this batteries depends on the materials inside. Will it be all used up after one cycle?
It is a single use battery… just like any primary battery.
If no water it will not work.
After filling with water should be used.
After discharged should be recycled or discarded. After one cycle it becomes waste.
According to the reviews (on tinydeal), this is supposed to be cyclable around 5 - 10 times. Afterwards it will contain less charges. I don’t know how this contradict the Aquacell statement… maybe the seal is not too good and vapor can escape?
I thought this was a bad idea at first, but then the infinite shelf life (great for emergency stash) and the fact it is not alkaLeak, plus the pricing, maybe the idea is ok.
“According to”, that tells me enough 
I wonder how they handle temperature extremes in their dry state. It might be prudent to have a couple as deep backup, for our car flashlights in desert climates, which means exposure to temps from a possible 160F during summer, to minus 20F during winter.