[[ GCSE Science/Electricity ]]. Electrolysis is the decomposition of certain types of substance using electricity. The types of substance that can be split are ionic substances.This just means that they are made of charged ions rather than neutral atoms.{Remember that an ion is just an atom that has either a positive or negative charge}. An example of an ionic substance is common table salt sodium chloride.he types of substance that can be split are ionic substances. This just means that they are made of charged ions rather than neutral atoms. {Remember that an ion is just an atom that has either a positive or negative charge}. An example of an ionic substance is common table salt sodium chloride.