Until now it has been assumed that lithium batteries have a limited lifespan, because the cell components degrade with each charge and discharge cycle. This process is not uniform, there are stages in the life of the batteries in which the degradation goes faster, and other times in which the speed decreases. In any case, The truth is that eventually lithium batteries stop working.
However, recent research carried out by Stanford’s Precourt Institute for Energy has discovered that It is possible to reverse this degradation process and make an old lithium battery work again. Even better than a battery in good condition.
The secret life of lithium batteries
The first thing to clarify is that There are two types of lithium batteries: lithium ion ones, which are currently the most used in the automotive industry, and lithium metal ones, or metallic lithium. In the former, the anode is made of graphite, and in the latter it is made of galvanized lithium. The latter have the potential to double the charging potential of the former, but are not yet widely used.
Both batteries suffer degradation processes that until recently were considered irreversible. In the case of lithium metal batteries, charging cycles cause the lithium material to be released., and a solid electrolyte interface (SEI) matrix is formed during battery discharges. This matrix captures the released lithium material, forming dendrites that reduce the battery’s charging capacity, until it stops working.
How to “revive” a degraded lithium battery
According to Dr. Yi Cui, director of the Precourt Institute for Energy at Stanford University, the idea came to a student, and at first it seems very simple. If the lithium metal battery suffers degradation processes when fully charged for long periods, perhaps Keeping it fully discharged for a long period could help reverse the deterioration process..
The institute’s team decided to test this hypothesis and the result could not be more surprising: Not only was the degradation process reversed, but the batteries recovered their storage capacity by 98.2%. A result even above the 96% of the lithium batteries in good condition that were used as a control.
When discharged and at rest, the SEI matrix dissolves in the electrolyte, the dendrites break down, and the lithium is released.. When it begins to receive charge again, the lithium joins again and contributes to the charging capacity of the battery.
How to apply this discovery to practical life
Lithium metal batteries are less common than lithium-ion batteries, but with this added advantage of reversing degradation, they may become more popular. The owners of this type of batteries in their cars They would have to completely empty their batteries every so often, maybe once a weekto prolong the useful life of this fundamental part in electric cars.
