electrolysis is a process involving decomposition of an iconic compound using electrical energy .. if u use 'inert' electrodes like carbon .. if u change the electrodes to say copper, it tends to take part in the 'reaction' (electrolysis) .. you can purify copper with using copper electrodes .. u tht process too ??
making cells or batteries is slightly different .. in alkaline batteries (zinc carbon batteries) the positive electrode is manganese oxide and the negative electrode is zinc .. note tht these metals act as electrodes and an electrolyte used may be an alkali (sodium hydroxide)
Butanol has a larger chain compared to ethanol .. due to this fact more energy is released in the process of 'burning' of butanol ..