Chemical Forums
Chemistry Forums for Students => Inorganic Chemistry Forum => Topic started by: Enthalpy on January 29, 2015, 11:50:15 AM
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Hello dear friends!
Growth of dendrites in rechargeable batteries is a common worry, said to preclude for instance metallic lithium which is replaced by less compact lithium compounds. Over use cycles, metal spikes grow over the electrodes, and when they reach the opposite electrode, end of the game, possibly with side effects.
Could that process resemble the roughening known at electrodeposition? At the electrode being covered, the hills offer a locally shorter path to the current, which concentrates there and lets the hills grow faster. The same could happen when charging a battery.
The remedy is known and commonly used for electrodeposition:
- Electrodeposition exaggerates the hills, removal smoothens the material (electropolishing);
- A strong current density exaggerates this effect, heat linders it;
- So the deposition is regularly interrupted by a short and strong removal, flowing the current in opposite direction;
- The proper intensities and durations achieve both a net deposition and net smoothening.
For a battery, this would translate into: interrupt regularly the gentle charge by a stronger and even shorter discharge. Even if the dendrites grow through an other process, polishing would help.
Is that already known and tried? I suppose yes, since the same people must have worked on electrodeposition and rechargeable batteries. If not, it's quickly experimented.
Thank you!
Marc Schaefer, aka Enthalpy