There is no access to electricity on Mt. Kilimanjaro, so it is highly recommended that you do not rely on anything (phone, camera, ereaders) that needs power to charge. You may consider items such as power banks and solar chargers, though these will add to your weight and have varying reliability. We can talk about this during our chat though you may want to poke around and do your own research as well!
Electricity will be available in all hotels, though you will need an adapter and/or converter for 230V, 50Hz.