Fig. 1: Battery operation.
From: Magnetic microscopy for operando imaging of battery dynamics
Batteries store and release energy by moving the active ions and electrons between a low-energy position in the positive electrode and a high-energy position in the negative electrode. The ions are transferred across the electrolyte, whereas electrons take up or release energy from an external circuit. This promotes or demotes electrons from low-energy 3d states in the transition metals of the positive electrode such as Co in the layered oxide LiCoO2 to high-energy states in the negative electrode related to the reduction of lithium ions to lithium metal.
