All batteries contain two electrodes: an anode and a cathode that can store electric power as chemical energy. The chemical reaction between the two electrodes has an ionic component that flows between the electrodes inside the battery and an electronic component that flows outside the battery. When discharged, electrons and ions flow from the anode to the cathode, and on charge the electrons and ions flow back from the cathode to the anode to restore the chemical energy.
Goodenough’s work in fabricating a discharged rather than a charged battery cell enabled removal of the metallic lithium traditionally used in the anode – and the source of its safety concerns due to anode dendrites whiskers forming on charge that can create an internal short-circuit with incendiary results – to be replaced by a carbon or alloy anode that can be charged many times without dendrites.
Not surprisingly, the Japanese SONY Corporation recognized the potential and used Goodenough’s concept and oxide cathode to produce the first commercial Li-ion battery with a carbon anode for the first wireless telephone. The rest, as they say, is history.