We have been focusing on single-use batteries whose electrical life ends after they surrender most of their energy. Although we hope their humans return them to recycling depots so their materials find another use. Today we move on to recharging a battery after it has gone flat, if its electrode design allows it. This hugely extends its usefulness, while adding relatively less carbon to the atmosphere.
Opportunities for Recharging a Battery
IMPORTANT WARNING – Please do not attempt to recharge a single use, non-rechargeable battery. Regardless of what some others may twitter, this practice is not safe and you could harm yourself.
Batteries that are made for recharging have electrode materials enabling a spent battery to return to its original state. Although they can only tolerate this a certain number of times, before the charge becomes too weak to be useful.
Recharging a Battery – The Chemistry Behind It
We can reverse the chemical reaction that caused a rechargeable battery to surrender its energy during discharge. After applying a suitable external current:
- The positive ions return to the anode through the electrolyte
- The electrons similarly return to the anode via the electrolyte
- This fully re-primes the battery. It is ready to perform again!
Recharging a Far from Perfect Solution
This process, while appearing almost magical is far from perfect. That’s because the return of electrons and ions to their original state is never as neat and tidy as before. Moreover, every discharge / recharge cycle degrades the electrodes a little more.
The battery progressively loses performance every time. Its crystals gradually change shape, especially during rapid recharges and charges. And as a result recharging a battery is not the panacea we hoped for.
However, we should not be dispirited. Battery research is receiving more attention than ever before. Good progress is being made with current technology. Meanwhile we wait for a future Volta, to create the next generation of energy storage.
More Information
Balancing Flow of Ions in the Electrolyte
