Diagram of the <a href="https://en.wikipedia.org/wiki/Electrical_double_layer" class="extiw" title="en:Electrical double layer">Electrical double layer</a>
<a href="//commons.wikimedia.org/wiki/User:Guillom" title="User:Guillom">Guillaume Paumier</a> (user:guillom)
CC BY-SA 3.0
<span class="int-own-work" lang="en">Own work</span>