Lithium Ion Batteries

Lithium Ion Batteries Rely on Microporosity to Transmit the Electric Charge

The positive electrode of lithium ion battery, the Cathode, is made of highly purified lithium oxide, and the negative electrode, the anode, is made of graphite. Both are sandwiched to the conductive surfaces, usually made of aluminum or copper. Structurally the electrode and conductive surface are made to be one unit. 
The separator, soaked in electrolyte ensures that that short circuit does not take place causing explosion or fire. Actually, the separator does not separate but only rations the ion flow between the electrodes. The property called microporosity defines the speed, efficiency and overall quality of ion transfer between the lithium oxide and carbon electrodes.
What does the interaction between the two electrodes consist of? When the battery is being charged the ion traffic is directed from the lithium cathode towards the carbon anode; when discharged, ions travel back.
The membrane separator controls the speed of the traffic and the electrolyte makes sure every remote corner of electrode is reached, thus guaranteeing the efficiency. Overall performance is reached when every component is able to reach its full chemical potential given proper architecture and the quality of materials permits.