Storage of Eletrolyte KOH?

A stainless steel container with a Teflon coating perhaps?

That's one hell of an ambient. Are you storing in the Middle East or Africa?

Have found no problem storing it in black polypropelene containers, I dont think they will be a problem at that temperature. If that is your ambient temperature I would not leave them in direct sunlight.

KOH in a sealed black or clear polyethylene or propylene container will last for decades as long as air is kept out and water loss is preventedThe CO2 from the air gradually reacts with it to form a carbonate and in time the crystals will expand and break the container if air gets in. Same thing seen with Nicad batteries and CO2

The chemical compound potassium hydroxide, (KOH) sometimes known as caustic potash, potassa, potash lye, and potassium hydrate, is a metallic base. It is very alkaline and is a "strong base", along with sodium hydroxide, lithium hydroxide, calcium hydroxide, barium hydroxide and strontium hydroxide.

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El compuesto químico del hidróxido de potasio, (KOH) conocido a veces como potasa cáustica, potassa, lejía de la potasa, e hidrato del potasio, es una base metálica. Es muy alcalino y es una "base fuerte", junto con el hidróxido del sodio, el hidróxido del litio, el hidróxido de calcio, el hidróxido de bario y el hidróxido del estroncio.

Properties: Density and phase 2.044 g/cm³, solid - Solubility in water 1100 g/L (25 °C) - Melting point 406 °C - Boiling point 1320 °C - Vapour Pressure 1.3hPa (719 ° C) - Basicity (pKb) -2.29.

How to store: In a glass bottle or polypropelene containers, with hermetic cover.

Black polypropylene carboys. Keep it in a cool place and tightly capped to prevent absorption of atmospheric CO2 and other acidic gasses.

It is common for this material to be stored in polypropylene tanks in UK ambient temperatures.