Maximum,meaning the most. And ion,which is an atom or group of atoms with an electrical charge.

VOA: special.2010.05.30

Nerve cells use electrical particles to communicate with each other.

VOA: special.2010.10.26

"Someone could attack the industrial control systems that control all the valves, all the distribution systems, and are used to turn on and off various aspects involved with energy and the electrical power grid and oil and gas distribution networks,".

VOA: standard.2009.08.11