Chemistry of a Battery Part 2: Electrolyte

The electrodes we see peeping out of battery casings are just one part of the electro-chemical scenario. That’s because they can’t do much on their own without their companion electrolyte. In fact, electrolyte makes or breaks the chemistry of a battery. It can be liquid, gel or even a solid substance provided it allows charged electrons to pass through.

Principles of Equilibrium in The Chemistry of Battery

Nature always tries to strike a balance and we need harmony in our batteries too. The anode electrode sends negative electrons through a connected device during discharge. However, it also produces positive electrons inside the battery to compensate.

The negative electrons pass through the device during discharge where they do their work. Then they travel further through the wire until they reach the positive cathode electrode. This restores its electro-chemical balance by drawing the positive ones from the anode.

But it stands to reason there must be a controlling mechanism to ensure this happens in an orderly fashion. Otherwise, the electrons could flood the electrodes and jam the chemistry of the battery up.

The Electrolyte Is the Key to Orderly Electron Flow

The electrolyte provides a medium through which electrons flow between electrodes in orderly fashion, without them touching and short circuiting. Battery engineers introduce semi-permeable partitions between them to regulate the flow rate further.

This process continues while the device is turned on, until all electrons have travelled from the anode to the cathode. At this stage the battery is technically ‘dead’, although it does still contain some charge.

But the electrolyte has one more trick in store, assuming the battery is a rechargeable type. The electrons originally ‘shuttled’ when the device drew the electrical charge. But if we put an electrical charge into a spent battery, then the electrolyte allows the electrons to return to the anode until the battery is fully ‘charged’ again.